Qualification: 
Ph.D
st_malini@cb.amrita.edu

Dr. Thirumalini S. received B.E., M.E. & Ph.D. Degrees from Coimbatore Institute of Technology.

Her areas of interest are Internal Combustion Engines, Combustion Modeling, and Computational Fluid Dynamics. She has guided a number of graduate student projects on In-cylinder flow dynamics, Structural analysis of Thermal Systems, Investigations on use of alternate fuels, HVAC and Low-temperature combustion studies. She is currently guiding 7 Ph.D. scholars and one student had graduated last year. She leads the research activity at the Amrita Automotive Research & Technology Centre (AARTC) and is currently involved in setting up test facility for Power train Emission Studies with Compliance for Euro VI and beyond.

Dr. S. Thirumalini received the “Women Engineer award – 2008” from the Institution of Engineers, Tamilnadu state chapter, and “Ralph R.Teetor Educational Award” from SAE International at Michigan, Detroit, 2010. She received the “Guru Award” from SAEINDIA Foundation in 2014.

She is a member of SAEINDIA and Institution of Engineers (India) and a Life Member of the Indian Society for Technical Education and ISAMPE.

Research Expertise

Power train development and testing, HVAC studies, Thermal analysis, Simulation of combustion, Low-temperature combustion, and emission analysis

Ongoing Research

  • Combustion analysis in GDI engines for improvement in specific fuel consumption.
  • Multi-attribute optimization of combustion by simulation and validation.
  • Studies on NOx reduction by SCR exhaust after treatment to maximize NH3 conversion.
  • Studies on the relation of instantaneous emissions to legislated emissions for different test cycles and engine types and designs, various fuels and their possible correlation.
  • Frictional studies in engines

Funded Projects

  • DST- TSDP – ARCI & Amrita 2015
  • DST - FIST 2016

Teaching

  • Internal Combustion Engines
  • Tribology in Engines
  • Combustion and Emission in Engines
  • Thermodynamics
  • Refrigeration & Air conditioning
  • Heat Power Engineering

Publications

Publication Type: Patent

Year of Publication Title

2019

K. Rushiraj Ashok and Dr. Thirumalini S., “Design of a new horizontal K-type configuration for internal combustion engine”, 2019.

Publication Type: Journal Article

Year of Publication Title

2019

S. R Godson, Dr. Thirumalini S., and Tulapurkar, C., “Numerical Modelling of Methanol-Gasoline Blends in PFI Spark Ignition Engines”, IOP Conference Series: Materials Science and Engineering, vol. 577, p. 012148, 2019.[Abstract]


According to present statistics, India is the 6th highest consumer of fossil fuels in the world. This raises high concerns in terms of emissions and import bills. Most recently India has taken stand to promote alternate fuels such as Methanol/biofuels and blends as substitute for conventional fuels. The use of blended fuel, without change in configuration of engine or in operating parameters can lead to lower performance. Operating parameters are to be optimized to obtain improvement in performance. Optimization requires rigorous experimentation, which increases cost of production for automotive manufacturers and simulation facilitates an early understanding of the engines behaviour. In this study, a 0.8 litre, 27.6 kW PFI engine is modelled and analysed to investigate the response of methanol-gasoline blends and experimental work is conducted for validation. Results indicated, with methanol blended up to 20% by volume, engine brake power was lower than base line gasoline but for blends of 20-50% by volume brake power and torque showed higher value than gasoline values. For M30, M40 and M50 with blend composition there was a proportionate increase in BSFC for all speed ranges.

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2019

Senthilkumar D., Dr. Thirumalini S., and Praveen, H. S. S. K., “Experimental investigation to improve performance and emission characteristics of a diesel engine by using n-butanol as additive to the biodiesel-diesel blends”, IOP Conference Series: Materials Science and Engineering, vol. 577, no. 1, p. 012102, 2019.[Abstract]


Fossil fuels are non-renewable resources and are limited in supply. The combustion of these fuels produces environmental pollution with the release of dangerous gases like Nitrogen oxides, Carbon monoxide and Carbonaceous soot. In this sense, fuel like biodiesel produced from vegetable oils can be considered as a better alternative to the fossil fuels. For this study, waste cooking oil biodiesel is used. In this work, the effect of addition of n-butanol on the performance and emission characteristics of diesel engine running at the speed of 2300 rpm is investigated. The biodiesel is prepared by transesterification process using KOH as catalyst. n-Butanol is added to B20 blend in varying volume percentages of 5, 10 and 15 to evaluate its effect on performance and emission characteristics. It is observed that BU15 possesses better performance characteristics among n-butanol blends compared to B20 with an average decrease of 18% in BSFC and increase of 21% in BTE at high loads. The experimental results showed that NOx and CO2 emissions were further reduced by 19% and 28% respectively with the addition of butanol. There has been reduction in smoke emissions by 4.7% but an increase of 22% in HC emissions for n-butanol blends.

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2019

Senthilkumar D. and Dr. Thirumalini S., “Investigation on Effect of Split Injection and Retarded Injection Timing on the Performance Characteristics of engines with Cashew nut shell biodiesel Blends”, Journal of Ambient Energy (Under Review), 2019.

2019

S. P. M. Vignesh, Srihari S., and Dr. Thirumalini S., “Effect of dual fuel injection on the emission characteristics of a single cylinder ci engine using alcohol diesel blends with preheated air”, International Journal of Engineering and Advanced Technology, vol. 8, no. 5, pp. 1395-1402, 2019.[Abstract]


In this study, experimental investigation is carried out on the performance and emission characteristics of diesel-methanol fuel blends with pilot injection. A single cylinder, four stroke, air cooled diesel engine is used for the study. The various methanol blend percentage by volume used in the engine are 5% and 10% in diesel. The engine is maintained at a constant speed of 2300 rpm with variable load conditions. Performance and emission parameters are observed on the engine using pilot injection and main injection strategy by preheating the intake air at the intake manifold. The methanol-diesel fuel blend is prepared by using mechanical stirring technique. The performance and emission characteristics are observed and compared with the base line diesel. It is observed that the brake thermal efficiency is increased for both the blends at higher load conditions when 10% pilot injection is used. A reduction in BSFC is also noticed for M5 and M10 blends. The emission parameters such as smoke, CO and HC are reduced when compared to baseline diesel. © BEIESP.

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2019

V. Charitha, Dr. Thirumalini S., Prasad, M., and Srihari S., “Investigation on performance and emissions of RCCI dual fuel combustion on diesel - bio diesel in a light duty engine”, Renewable Energy, vol. 134, pp. 1081-1088, 2019.[Abstract]


Reactivity Controlled Compression Ignition (RCCI) combustion has been established by modification of intake of a diesel engine. Studies were carried out on the existing engine with Conventional Diesel Combustion (CDC) and performance and emission parameters were recorded. Cotton seed biodiesel (COME) as low reactive fuel was injected into inlet manifold through a port fuel injector and diesel as high reactive fuel is injected in the cylinder through direct injection. Modified engine was tested for performance and emission characteristics. Simultaneous reduction in NOx and smoke emissions were observed with introduction of COME. CO2 emissions decreased marginally and unburnt hydrocarbons (UHC) decreased at lower percentages of COME and increased with higher percentages of COME. An increase in the Brake Thermal Efficiency (BTE) of the engine is observed at all loads. Exhaust Gas Temperature (EGT) and Brake Specific Fuel Consumption (BSFC) are lower in RCCI mode as compared to CDC. The optimum operating range of COME is observed with 10–20% of COME, which has 22% of average decrease in NOx and 30% decrease in the smoke emissions. © 2018 Elsevier Ltd

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2018

S. D. Kumar, Srihari S., and Dr. Thirumalini S., “Effect of inlet air temperature on SI engine fueled with diethyl ether-gasoline blends”, Journal of Mechanical Engineering and Sciences, vol. 12, no. 4, pp. 4044-4055, 2018.[Abstract]


In this study the performance and emission characteristics of spark ignition genset engine fueled with gasoline and diethyl ether (DEE) blends are carried out. The DEE blends are varied from 3%, 6% and 9% by volume in gasoline. A four-stroke single cylinder constant speed spark ignition engine is used for the experiments. The variation in fuel consumption and exhaust emission with respect to two different inlet air temperatures are studied. The concentration of exhaust emissions such as HC, CO, NOx is observed. The parameters such as inlet air temperature, brake specific fuel consumption, relative air to fuel ratio are also measured. It is noticed that 6% DEE blend in gasoline reduced almost reduced HC emission about 57% and also considerable reduction in CO emission at lower air intake temperature. The addition of diethyl ether has an improvement in performance and significant reduction in HC, CO and NOx emissions. © Universiti Malaysia Pahang, Malaysia

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2018

R. Harsh, Srivastav, H., Balakrishnan, P., Saini, V., Senthilkumar D., Rajni, K. S., and Dr. Thirumalini S., “Study of Heat Transfer Characteristics of Nanofluids in an Automotive Radiator”, IOP Conference Series: Materials Science and Engineering, vol. 310, no. 1, p. 012117, 2018.[Abstract]


This paper presents an experimental study on heat transfer using nanofluid as coolants in engines. Previous studies shows that Al 2 O 3 is found to be more effective in heat transfer due to its high conductive property which is found to increase with concentration. Particles having diameter in the range 10 -3 to 10 -6 m have low thermal conductivities and cause clogging in the flow section along with significant friction and are highly unstable in solution. Nanoparticles on the other hand are easily dispersed and cause minimal clogging or friction in the flow. In the present work, ethylene glycol-water solution is taken as a base fluid for nanoparticle dispersion. The ratio of water to ethylene glycol used is 80:20 and it has been noted out that heat conduction improved with increasing fraction of ethylene glycol. The experiments were conducted with flow rate of 4,5,6 and 7 L/min and the air flow rate inside the duct was kept constant at 4.9 m/s. The temperature of water in the reservoir is kept at 70°C. The nanoparticles used in this experiment are Cu and TiO 2 having particle size less than 80nm. Result shows that there is an improvement of 24.5% in the overall heat transfer coefficient and there was also an increase of 13.9% in the heat transfer rate compared to the base fluid (80:20 Water: EG solution).

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2018

S. A. Kumar, Dr. Thirumalini S., Mohankumar, P., R. Sundar, R., and Aravind, C., “Simulation study on variants of ABS”, International Journal of Engineering and Technology(UAE), vol. 7, no. 3.6, pp. 97-100, 2018.[Abstract]


The performance characteristics of different variants of Anti-Lock Braking System (ABS) in a normal passenger car is investigated. ABS prevent lock-up of wheels and maintains steer ability of the vehicle during braking. Vehicle stopping distance, brake pressure, wheel slip and slide-slip are made using Simulink software and system study was conducted an investigation is done. The variants of ABS taken for the study are 2-channel ABS (front wheels), Cross-ABS (alternate wheels: front left and rear right) and full (four channel) ABS. The Simulink model was interfaced with IPG Carmaker and simulation was performed to include the aerodynamics, tire friction and road friction. The results of the simulation were validated to obtain conclusions on the braking performance for different variants of ABS. © 2018 Authors.

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2018

Dr. Radhika N, Dr. Thirumalini S., and Shivashankar, A., “Investigation on Mechanical and Adhesive Wear Behavior of Centrifugally Cast Functionally Graded Copper/SiC Metal Matrix Composite”, Transactions of the Indian Institute of Metals, vol. 71, no. 6, pp. 1311-1322, 2018.[Abstract]


The objective of this work is to fabricate functionally graded unreinforced copper alloy (Cu–10Sn) and a Cu–10Sn/SiC composite (Øout100 × Øin70 × 100 mm) by horizontal centrifugal casting process and to investigate its mechanical and tribological properties. The microstructure and hardness was analysed along the radial direction of the castings; tensile test was conducted at both inner and outer zones. Microstructural evaluation of composite indicated that the reinforcement particles formed a gradient structure across the radial direction and maximum reinforcement concentration was found at the inner periphery. Hence maximum hardness (205 HV) was observed at this surface. Tensile test results showed that, the tensile strength at inner zone of composite was observed to be higher (248 MPa) compared to that of the outer zone and unreinforced alloy. As mechanical properties showed better results at inner periphery, dry sliding wear experiments were carried out on the inner periphery of composite using pin-on-disc tribometer. Process parameters such as load (10–30 N), sliding distance (500–1500 m) and sliding velocity (1–3 m/s) were analyzed by Taguchi L27 orthogonal array. The influence of parameters on wear rate was analyzed by signal-to-noise ratio and analysis of variance. Analysis results revealed that load (54{%}) had the highest effect on wear rate followed by sliding distance (18.2{%}) and sliding velocity (3.7{%}). The wear rate of composite increased with load and sliding distance, but decreased with sliding velocity. Regression equation was developed and was validated by confirmatory experiment. Worn surface of composite was observed using scanning electron microscopy and transition of wear was observed at all extreme conditions.

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2017

V. Salamon, Senthilkumar D., and Dr. Thirumalini S., “Experimental Investigation of Heat Transfer Characteristics of Automobile Radiator using TiO2-Nanofluid Coolant”, IOP Conference Series: Materials Science and Engineering, vol. 225, p. 012101, 2017.[Abstract]


The use of nanoparticle dispersed coolants in automobile radiators improves the heat transfer rate and facilitates overall reduction in size of the radiators. In this study, the heat transfer characteristics of water/propylene glycol based TiO2 nanofluid was analyzed experimentally and compared with pure water and water/propylene glycol mixture. Two different concentrations of nanofluids were prepared by adding 0.1 vol. % and 0.3 vol. % of TiO2 nanoparticles into water/propylene glycol mixture (70:30). The experiments were conducted by varying the coolant flow rate between 3 to 6 lit/min for various coolant temperatures (50°C, 60°C, 70°C, and 80°C) to understand the effect of coolant flow rate on heat transfer. The results showed that the Nusselt number of the nanofluid coolant increases with increase in flow rate. At low inlet coolant temperature the water/propylene glycol mixture showed higher heat transfer rate when compared with nanofluid coolant. However at higher operating temperature and higher coolant flow rate, 0.3 vol. % of TiO2 nanofluid enhances the heat transfer rate by 8.5% when compared to base fluids.

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2017

Dr. Thirumalini S. and Nagarajan, V., “Investigations on Emission of Nano Particulates Under Free Acceleration Test Condition”, International Journal of Nanoparticles, vol. 9, no. 4, pp. 234 – 243, 2017.[Abstract]


Considering the dangerous effects of ultrafine particles and air quality concerns worldwide, this work investigates the possibility of identifying operating criterion over which there is a greater tendency of formation of nanoparticle emissions in Diesel engines. The objective of this analysis is to study the emission of particles in the size range of 10 nm to 700 nm by subjecting a diesel engine to free acceleration tests. Details on the emission characteristics such as Particulate number, Particle mass, Particle diameter and the Lung deposition surface area in the size range 10–700 nm during specific conditions of acceleration and deceleration has been studied in this work. Maximum effect of the particles occurs during rapid acceleration. At idle speed, the Particle number, particle mass and Lung deposition surface area are very low indicating that the nanoparticle formation is low at idle condition. With increase in Particulate number, there is an increase in the Particulate mass and the LDSA. The particulate diameter is distributed across the PN range.

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2017

M. M. Mathew, Bathe, R. N., Padmanabham, G., R. Padmanaban, and Dr. Thirumalini S., “A study on the micromachining of molybdenum using nanosecond and femtosecond lasers”, The International Journal of Advanced Manufacturing Technology, 2017.[Abstract]


Laser micromachining is an advanced machining process in which machining is achieved by focusing a laser beam to melt and vaporize the material. The primary aim of this work is to fabricate a control grid for an electron gun using laser micromachining. Initially, line scribing and 2D profiling experiments are performed on a 130-$μ$m molybdenum plate to compare the surface quality and material removal rate of nanosecond and femtosecond lasers. The effects of laser processing parameters such as average power, repetition rate, and the feed rate on the width, depth, material removal rate, and cut quality of both the nanosecond and femtosecond lasers are studied. During micromachining using the nanosecond laser, melting and recasting of the metal around the machined sites are observed, resulting in the formation of heat-affected zone. During machining using the femtosecond laser, ultrafast laser pulses are used, which result in the absence of heat-affected zone. The surface roughness obtained using the femtosecond laser for creating a 2D profile is 0.187 $μ$m, while using the nanosecond laser, the roughness value obtained is 1.89 $μ$m. The femtosecond laser is used to successfully machine the 3D profile of the control grid, adopting the optimized parameters obtained from the line scribing and 2D profiling experiments. The average width of the grid line was measured as 149.89 $μ$m which is very close to the required dimension of 150 $μ$m

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2017

S. K. Sreekala and Dr. Thirumalini S., “Study of flow performance of a globe valve and design optimisation”, Journal of Engineering Science and Technology, vol. 12, pp. 2403-2409, 2017.[Abstract]


Valves control the fluid flow and pressure in a system or a process. Globe valves have good throttling ability, which permits its use in regulating flows. Detailed understanding of flow in Globe valve with cage apertures of various shapes and its impact on the flow characteristics and optimization was carried out. The computational study was carried out using FLUENT, a finite volume based code. Grid sensitivity test were done and the results validated experimentally. The effect of aperture configuration on flow characteristics and valve coefficient was studied to arrive at optimum value. Valve coefficient was found to be dependent on aperture shape and is maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established. © School of Engineering, Taylor’s University.

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2017

Srihari S. and Dr. Thirumalini S., “Investigation on reduction of emission in PCCI-DI engine with biofuel blends”, Renewable Energy, vol. 114, pp. 1232 - 1237, 2017.[Abstract]


Immense potential is seen in Homogenous Charge Compression Ignition (HCCI) engines as an alternative to conventional Compression Ignition (CI) engines as it can simultaneously reduce oxides of nitrogen (NOx) and soot while maintaining high efficiency. The challenges are predominantly control of combustion and limited operating ranges. Mitigation of these challenges using PCCI-DI is explored in this work. A pilot injector is used to supply a small quantity of premixed charge of fuel and air to the engine followed by direct injection through the main injector. An added advantage is dual fuel capability and improvement of combustion characteristics. Two fuels namely diesel and a blend of ethanol and diesel (containing 15% of ethanol by volume, called E15D) are used in four different combinations for the pilot and main injection. The emission characteristics of each combination were then compared with the conventional mode of operation. The four combinations or modes of operation with PCCI setup were Diesel-Diesel (pilot-main fuel), Diesel-E15D, E15D-Diesel, and E15D-E15D. The results of the experiment indicate that the Diesel-E15D mode is comparatively the best mode of operation due to its lower NOx and smoke emissions.

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2017

M. Arivarasu, Roshith, P., Dr. Padmanaban R., Dr. Thirumalini S., Prabhakar, K. V. Phani, and Padmanabham, G., “Investigations on metallurgical and mechanical properties of CO2 laser beam welded Alloy 825”, Canadian Metallurgical Quarterly, pp. 1-13, 2017.[Abstract]


In the research work, an attempt is made to join nickel-based alloy 825 by employing CO2 laser beam welding. Successful full penetration weld joint of a 5 mm thick plate is achieved with a very low heat input of 120 J-mm−1. Narrow weld bead width of 0.6 mm at the root and 1.6 mm at the cap is observed fusion zone; the interface and base metal microstructures have been examined using both optical and scanning electron microscopic techniques to understand the microstructural changes which have occurred due to laser welding. A range of tests of Vickers micro hardness, tensile and impact tests had been performed on the weldment to ascertain the mechanical properties of the joint. Tensile failure at the base metal and a 180° root bend test conducted on the weldment ascertain the soundness of the weld joint produced. An attempt is made to correlate the microstructure and mechanical properties of the weldment. Intermetallics TiN and Al4C3 observed in the SEM/EDS analysis at the fusion zone are found to have improved the weld metal strength and hardness. © 2017 Canadian Institute of Mining, Metallurgy and Petroleum

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2017

Srihari S., Dr. Thirumalini S., and Prashanth, K., “An experimental study on the performance and emission characteristics of PCCI-DI engine fuelled with diethyl ether-biodiesel-diesel blends”, Renewable Energy, vol. 107, pp. 440 - 447, 2017.[Abstract]


Abstract The possible depletion of fossil fuels has created the need for alternate fuels worldwide and engine developers are prompted to investigate the viability of such fuels. Further, stringent emission norms have created the need for low emission engines. The objective of this work is to evaluate the effect of diethyl ether in biodiesel-diesel blends on the performance and emission characteristics in a Premixed Charge Compression Ignition-Direct Injection (PCCI-DI) engine. Biodiesel obtained from cotton seed oil is used for this study. PCCI-DI engine is operated with main injection and pilot injections with varying percentages of \{DEE\} along with 20% biodiesel blended with neat diesel. The emission characteristics show a discernible reduction in emissions (NOx, \{CO\} and HC) vis-a-vis biodiesel-diesel blends. Benefits like reduction in the quantum of smoke produced and improvement in Brake thermal efficiency are also noticed in specific cases.

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2016

S. K. Sreekala and Dr. Thirumalini S., “Effect of cage configurations on flow characteristics of globe valves”, World Journal of Engineering, vol. 13, pp. 61–65, 2016.[Abstract]


Purpose Globe valves have good throttling ability, which permits its use in regulating flows. This paper aims to understand in detail the globe valve with different cage configurations and its impact on the flow characteristics that was carried out. Design/methodology/approach The computational study was carried out using FLUENT, a finite volume-based numerical code. Grid sensitivity tests were done and the results were validated experimentally. The effect of cage configuration on flow characteristics and valve coefficient was studied and optimised. Findings Valve coefficient was found to be dependent on cage configuration and reaches its maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established. Originality/value Studies related with caged-type globe valves having different configurations are useful for improving their flow performance. In the present investigation, globe valves with different cage configurations and throttle positions are modeled to find out the valve coefficient, pressure and velocity contours inside and outside the cage and is validated with experimental results. More »»

2016

P. Deepak, Jualeash, M. J., Jishnu, J., Srinivasan, P., Arivarasu, M., Dr. Padmanaban R., and Dr. Thirumalini S., “Optimization of process parameters of pulsed TIG welded maraging steel C300”, IOP Conference Series: Materials Science and Engineering, vol. 149, p. 012007, 2016.[Abstract]


Pulsed TIG welding technology provides excellent welding performance on thin sections which helps to increase productivity, enhance weld quality, minimize weld costs, and boost operator efficiency and this has drawn the attention of the welding society. Maraging C300 steel is extensively used in defence and aerospace industry and thus its welding becomes an area of paramount importance. In pulsed TIG welding, weld quality depends on the process parameters used. In this work, Pulsed TIG bead-on-plate welding is performed on a 5mm thick maraging C300 plate at different combinations of input parameters: peak current (Ip), base current (I b ) and pulsing frequency (HZ) as per box behnken design with three-levels for each factor. Response surface methodology is utilized for establishing a mathematical model for predicting the weld bead depth. The effect of Ip, I b and HZ on the weld bead depth is investigated using the developed model. The weld bead depth is found to be affected by all the three parameters. Surface and contour plots developed from regression equation are used to optimize the processing parameters for maximizing the weld bead depth. Optimum values of Ip, I b and HZ are obtained as 259 A, 120 A and 8 Hz respectively. Using this optimum condition, maximum bead depth of the weld is predicted to be 4.325 mm.

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2016

G. Kumar and Dr. Thirumalini S., “Effect of lubricating oil temperatures on fuel consumption and emissions under cold start conditions for a diesel engine”, SAE International, 2016.

2016

S. K. Sreekala and Dr. Thirumalini S., “Investigation on aerodynamic noise evaluation and atte nuation in a glob e valve us ing CFD analysis”, International Journal of Multiphysics, vol. 10, pp. 43-51, 2016.[Abstract]


Noise pollution will soon become the third greatest menace to the human environment after air and water pollution. Since noise is a by-product of energy conversion, there will be increasing noise as the demand for energy for transportation, power, food, and chemicals increases. In the field of control equipment, noise produced by valves has become a focal point of attention. In this paper aerodynamic noise evaluation of a globe valve was carried out using a three dimensional Computational Fluid Dynamic technique(CFD). The results obtained from numerical analysis are compared with the experimental measurements and are found to be in good agreement. Reduction in sound pressure level was achieved by doubling the number of flow passages in the cage at full open condition and at the same operating conditions. Hence sound attenuation is established by changing the cage configuration with no change in total area of flow passage in the cage. More »»

2015

A. Jacob Zacharias and Dr. Thirumalini S., “Impact of Increase in Intake Air Temperature on Emission Characteristics of a Gasoline Ethanol Blended SI Engine during Cold Start”, International Journal of Applied Engineering Research, vol. 10, no. 19, pp. 0973-4562, 2015.

2015

J. James Cheeran, Dr. Padmanaban R., Dr. Thirumalini S., and .Bhaskar, V., “Design and Optimization of a Diesel Engine Connection Rod”, International Journal of Applied Engineering Research, vol. 10, no. 32, 2015.

2015

K. P. Vasudevan Nambeesan, Parthiban, R., K Kumar, R., Athul, U. R., Vivek, M., and Dr. Thirumalini S., “Experimental study of heat transfer enhancement in automobile radiator using Al^2^O^3 water-ethylene glycol nanofluid coolants”, International Journal of Automotive and Mechanical Engineering, vol. 12, pp. 2857-2865, 2015.[Abstract]


An experimental study on heat transfer enhancement in an automobile radiator using Al2O3/water–ethylene glycol (EG) nanofluids is carried out. Heat transfer enhancement studies can help in the design of lighter and more compact radiators for the same given load, which in turn can improve the fuel economy of the automobile. A closed loop experimental setup is designed using a commercial automobile radiator for the study. The effect of adding EG to water on the overall heat conductance (UA) is studied using two mixtures of water–EG proportions, 90:10 and 80:20 (by volume). They showed a reduction in UA by 20% and 25% respectively. Experiments have also been done using Al2O3/water–EG nanofluids. The nanofluid was prepared using an 80:20 mixture and 0.1% (vol.) of Al2O3 nanoparticles. The addition of nanoparticles enhanced the heat transfer performance by 37 %. All the experiments have been conducted at a constant coolant flow rate and coolant inlet temperatures varying from 40 oC to 70 oC. The results showed that the heat transfer performance of the radiator reduced with the addition of EG and increased with the addition of nanoparticles to the water–EG mixture. More »»

2015

S. Prabhakar.N, Senthilkumar D., and Dr. Thirumalini S., “Analysis of Regenerator Matrix in a Gamma Type Solar Stirling Engine”, International Journal of Applied Engineering Research (IJAER), vol. 10, no. 19, 2015.

2015

A. Krishnan and Dr. Thirumalini S., “Investigation of cold start and Idling emission characteristics of ethanol-gasoline blends in SI Engine”, International Journal of Applied Engineering Research, vol. 10, no. 17, pp. 37601-37604, 2015.[Abstract]


Increased emission levels are normally experienced in spark ignition (SI) engines at cold start and idling conditions. Carbon monoxide (CO) and unburned hydrocarbons (HC) are the main pollutants contained in the exhaust gas. This experimental work indicates a possible solution for reducing HC and CO emissions from a commercial spark ignition engine by blending ethanol with gasoline during the initial conditions. To the commercial available unleaded gasoline, in different percentage by volume varying between 0% (E0) and 30% (E30), ethanol was blended, for evaluating cold start and idling emissions. The pollutants measured were HC, CO, CO2. The test results indicated that, the HC and CO emissions at cold start and idling reduced considerably compared to base gasoline as ethanol was blended with gasoline. Among the blends E5, E10, E15, E20, E25 and E30 which were tested, the E15 ethanol-gasoline blend showed the maximum reduction in CO and HC emissions at cold start and idling conditions.

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2015

M. Mohan and Dr. Thirumalini S., “Experimental investigation of evaporative emission with variation in material characteristic and fuel levels”, International Journal of Applied Engineering Research, vol. 10, no. 17, pp. 38241-38244, 2015.[Abstract]


The contribution of evaporative emission to the total emission from a vehicle is substantial and has become critical due to stringent emission regulations. Hence it is imperative to study the variation in evaporative emission and factors responsible for them. The material of construction of the fuel tank and the fuel level in that tank are the two parameters selected for this investigation. Two fuel tanks of equal dimension were fabricated with polycarbonate and mild steel. Experiments with various fuel levels were conducted in a mild steel fuel tank. The results indicated a higher evaporative emission levels from polycarbonate fuel tank when compared to mild steel tank which explained the effect of permeability in evaporative emission. The emission rates were found to be reducing with increasing fuel levels and this was due to the reduction in volume of free air inside fuel tank and reduced surface area at fully filled condition.

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2015

M. Vigneswaran and Dr. Thirumalini S., “Experimental investigation of using n-hexanol as additive to n-butanol/diesel blends in diesel engine to study the emission and performance characteristics”, International Journal of Applied Engineering Research, vol. 10, no. 18, pp. 38984-38988, 2015.[Abstract]


This work describes the effect of n-butanol and n-hexnol as fuel blends to check the performance and the emission levels of a DI diesel engine for various loads at constant engine speed. The fuels proportions required to be tested are, B5H (n-butanol 5%, 10% n-hexanol along with 85% diesel in volume), B10H, B15H, B20H and B25H (Hexanol added to the blends are constant). Experiments were conducted on unmodified 4-stroke diesel engine of single cylinder and naturally aspirated one. The engine is tested in idle and various loading conditions with the help of dynamometer by using the test fuel blends. When the blends were compared with diesel fuel, brake specific fuel consumptions are higher for alcohol blends were observed. The results displayed that smoke emissions and carbon monoxide emissions reduce while HC emissions tend to increase with blend proportions present in the fuel. Increasing the blend proportions increases the NO emissions.

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2015

J. Koti, M., V., and Dr. Thirumalini S., “Study of heat transfer characteristics of Al2O3/water-propylene glycol nanofluid as a coolant in an automotive radiator”, International Journal of Applied Engineering Research, vol. 10, no. 16, pp. 37105-37109, 2015.[Abstract]


An experimental study on overall heat transfer performance of an automobile radiator using Al<inf>2</inf>O<inf>3</inf>/water- propylene glycol nanofluids has been conducted. Enhancement of Heat transfer in a radiator leads to a compact radiator, which in turn increases fuel efficiency and thus decreases cost. Experimental setup was developed using an automobile radiator. The effect of overall heat transfer conductance (UA) of Propylene Glycol (PG) added to water in two different proportions (80:20 and 70:30) has been studied. In addition to that, experiments are also conducted using Al<inf>2</inf>O<inf>3</inf>/water-PG nanofluids. The nanofluid is prepared by addition of 0.1% and 0.2% Al<inf>2</inf>O<inf>3</inf> nanoparticles to the 70:30 water-PG mixtures. The experiments have been conducted with a constant flow rate and with the temperatures varying form 70°C to 90°C. The study showed that there was an increase in overall heat conductance value with addition of nanoparticles to water-PG mixtures. With addition of 0.2 vol% of alumina particles there was an increase in UA by 9%. © Research India Publications.

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2014

V. Sundaram G. and Dr. Thirumalini S., “Experimental Study of Emission and Performance of Single Cylinder Diesel Engine Running On Groundnut Oil Based Biodiesel”, International Journal of Scientific & Engineering Research, vol. 5, no. 7, 2014.[Abstract]


The primary objective of this project was to study the effect of Groundnut Oil based Biodiesel on a CI engine operating at a constant speed under a range of loads. Biodiesel is being considered nowadays as an alternative to Petro-diesel, with advantages in favor of Biodiesel being it’s lowered emissions and performance comparable to diesel. This experiment was done by synthesizing Biodiesel from Groundnut oil and mixing it in different ratios with diesel to run a Single Cylinder Field Marshall Diesel engine and thereby obtaining the different performance and emission characteristics for the Biodiesel. More »»

2013

S. Ajit and Dr. Thirumalini S., “Investigation on Evaporative Emission from a Gasoline Polycarbonate Fuel Tank”, nternational Journal of Research in Engineering and Technology (IJRET), vol. 2, no. 12, pp. 46-49, 2013.

2013

A. A, Dr. Thirumalini S., and Padamanaban, V., “A Comparison of Fuel Properties between Fractionated and Non-Fractionated Composition of Micro Algae Based Biodiesel”, SAEINTERNATIONAL, 2013.[Abstract]


In many developing countries around the world, the plan of producing sufficient biodiesel (EN 14214) to meet the mandate of 20% blending with the diesel fuel (EN 590) was unachievable particularly due to two main reasons - the unavailability of sufficient feedstock and lack of high yielding drought tolerant plant based feed-stocks. Also, the production of biodiesel from these plant based bio-degradable source such as vegetable oil competes with the farm land utilization meant for growing food crops. Hence, the development of algae based technologies for a sustainable yield of biodiesel is gaining widespread importance. Industrial waste water effluent and sewage sludge water provides the best source of nutrients for the cultivation of microalgae. It is an indisputable fact that the recoverable oil yield from this unicellular organism is higher than that of any other food crop. In spite of these efficacies, some of the performance influencing parameters such as cold flow and oxidative stability still remain unfavorable to be used for automotive application. The present investigation deals with the trans-esterification of fractionated monounsaturated fatty acid to produce biodiesel with better low temperature properties and higher resistance to oxidation. It was observed that the increasing trend of thermal and prompt NOx emissions was influenced by average Degree Of Unsaturation (DOU) in the trans-esterfied compound, as it increased the adiabatic flame temperature during combustion. Finally, a comparison was made between the fractionated and non-fractionated biodiesel to understand the profile of key emission influencing characteristics of fuel such as DOU, iodine value, chain length, cetane number and oxidative stability.

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2012

Dr. Thirumalini S., ,, and Ramasubramanian, A., “Investigation on use of Plug-in Hybrid Electric Vehicle (PHEV) Technology Using Renewable Energy for an Autorickshaw”, Journal of KONES Powertrain and Transport, , vol. 19, pp. 383 – 394, 2012.[Abstract]


Availability and access to energy are considered as catalysts for economic growth. Harnessing clean energy for sustainable development is the keyword in today's scenario of energy utility. With the transport sector, contributing 32% of the total pollution levels, development and increased utilization of hybrid electric vehicles would be the best possible method to adopt for a cleaner and greener tomorrow. While lithium-ion technology is expected in production HEVs in the very near future, use in PHEVs are expected to be more gradual and dependent on solving the life, safety, and cost challenges. As a result, battery technologies for EVs are not fully matured due to range and charging-time issues, which are yet to be addressed. These two issues are normalized substantially in our study as the result of implementation of a battery swapping technique, thereby fast charging the batteries. This study focuses on battery systems as the electrical energy storage device and thus evaluates commercially available technologies for PHEV penetration in India through use of renewable energy sources such as wind and solar power in specific demographic areas as a typical example. The three-wheeler vehicle, popularly known as auto-rickshaws are one of the most important type of commercial transportation in majority of the Indian cities. An example of such a typical urban use auto rickshaw is considered for our study. This project has three main objectives: To convert the existing three wheeler into a PHEV and to determine the state of technology for PHEV batteries through an extensive literature review, develop a battery pack model and its charging cum swapping station at the above two places using renewable energy sources and finally to assess the environmental benefits of greenhouse gases emission, CO2 reduction and decrease in fuel consumption.

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2012

A. Ramasubramanian, Dr. Thirumalini S., Padmanaban, V., and Srinivasan, M., “Safe, Sustainable and Smart Charging of Plug in Hybrid Electric Vehicles (PHEVs)”, World Academy of Science, Engineering and Technology, vol. 69, pp. 1050 – 1055, 2012.

2012

V. Padmanaban, Dr. Thirumalini S., and Ramasubramanian, A., “Investigation On Use Of Plug-In Hybrid Electric Vehicle (Phev) Technology Using Renewable Energy For An Autoricksha”, Journal of KONES Powertrain and Transport, vol. 19, pp. 383 – 394, 2012.

2012

P. Vishnu, Dr. Thirumalini S., and Ajaykrishna, R., “Recent Advancements and Challenges in Plug-In Diesel Hybrid Electric Vehicle Technology”, International Journal of Electrical Engineering and Technology (IJEET), vol. 3, no. 1, pp. 316-325, 2012.

2009

Dr. Thirumalini S., .Lakshmikanthan, C., and .Dhandapani, S., “CFD Modelling for Parametric Investigation of Flow Through the Inlet Valve of a Four – Stroke Engine”, International Journal of Applied Engineering Research, vol. 4, no. 7, pp. 1369-1384, 2009.

Publication Type: Conference Paper

Year of Publication Title

2018

A. Thiruvengadam, Padmanaban, V., Pradhan, S., Besch, M., Ramanathan, S., and Dr. Thirumalini S., “Development of real-world vehicle activity based drive cycle for Indian cities using stochastic approach and performance validation”, in FISITA World Automotive Congress 2018, 2018.[Abstract]


With the promulgation of the real-world driving (RDE) emissions test procedure to the upcoming BS-VI legislation, it is becoming ubiquitous for OEMs to adopt vehicle testing drive cycles during testing that will more realistically reflect the on-road driving characteristics and emissions profile of modern powertrain technology of light duty vehicle segment. The present work spans the existing gap in knowledge in terms of validating the performance and robustness of vehicle testing drive cycles that will cater specific to the boundary conditions of Indian real-world driving activity and the preparedness for RDE legislation. The study involves on-road testing on three candidate vehicles across several days, to record essential vehicle operating characteristics describing the driving profile, road load characteristics, engine operating condition, metrological information and GPS based demographic location trace. The test routes included typical urban/sub-urban traffic patterns in Tier-1 Indian cities with frequent stop-go and increased traffic during rush-hours as well as portions of highway access. Markov chain method is used to construct drive cycle profile based on the specification of desired vehicle constraint parameters that is critical in representing acquired road load vehicle data. Further, the developed cycle was validated to compare the performance metrics to on-road driving activity. © 2018 FISITA. All rights reserved.

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2018

V. P. Kumar Reddy, Senthilkumar D., and Dr. Thirumalini S., “Effect of antioxidants on the performance and emission characteristics of a diesel engine fuelled by waste cooking sunflower methyl ester”, in IOP Conference Series: Materials Science and Engineering, 2018, vol. 310.[Abstract]


Biodiesel is a renewable, biodegradable fuel produced from vegetable oils and animal fats. Nonetheless, its extensive utilization is impeded by the auto-oxidation resulting in degradation of the fuel. Adding antioxidants to the biodiesel is a potential solution, but it might have an effect on the clean-burning characteristics of the fuel. This paper investigates the effect of antioxidants on the performance and emission characteristics of a diesel engine fuelled by the waste cooking sunflower methyl ester. The fuel samples tested include B10, B20, B30 and B40, among which B20 produced the best possible results. Antioxidants 2, 6-ditert-butyl-4-methylphenol (BHA) and 2(3)-tert-butyl-4-methoxy phenol (BHT) of two concentrations 1000 ppm, 2000 ppm were added to B20 to evaluate the effectiveness. B20BHA1000 had the best effect with an average decrease of 5.035%, 2.02% in brake specific fuel consumption (BSFC) and exhaust gas temperature (EGT) compared to B20. Regarding the emission characteristics it was observed that B20BHA1000 had produced an increase of 7.21%, 27.79% in NOx and smoke emissions and a decrease of 33.33% in HC emissions when compared to B20. On the whole, without any requirement of alteration in the diesel engines, B20 blends with antioxidant can be utilized as fuel. © Published under licence by IOP Publishing Ltd.

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2018

L. K. George, Tamilarasan, N., and Dr. Thirumalini S., “Design and analysis of magneto rheological fluid brake for an all terrain vehicle”, in IOP Conference Series: Materials Science and Engineering, 2018, vol. 310.[Abstract]


This work presents an optimised design for a magneto rheological fluid brake for all terrain vehicles. The actuator consists of a disk which is immersed in the magneto rheological fluid surrounded by an electromagnet. The braking torque is controlled by varying the DC current applied to the electromagnet. In the presence of a magnetic field, the magneto rheological fluid particle aligns in a chain like structure, thus increasing the viscosity. The shear stress generated causes friction in the surfaces of the rotating disk. Electromagnetic analysis of the proposed system is carried out using finite element based COMSOL multi-physics software and the amount of magnetic field generated is calculated with the help of COMSOL. The geometry is optimised and performance of the system in terms of braking torque is carried out. Proposed design reveals better performance in terms of braking torque from the existing literature. © Published under licence by IOP Publishing Ltd.

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2017

N. Tamilarasan, Dr. Thirumalini S., Nirmal, K., Ganapathy, K., Murali, K., and Srinath, H., “Design and Simulation of Ferrofluid Tactile Screen for Braille Interface”, in International Conference on Robotics and Automation for Humanitarian Applications, RAHA 2016 - Conference Proceedings, 2017.[Abstract]


The lack of eyesight is a severe obstacle faced by the blind and limits their access to technology. Developments in assistive technology can be traced from the implementation of braille through engraving and embossing the script. With the growth of digital age, braille is included in keyboards and number pads and more recently as mechanical refreshable braille displays with integrated audio systems [8]. However, such systems are extremely expensive to purchase and maintain. Existing displays have a very low resolution and are bulky [5]. This project explores developments in ferrofluids, a type of magnetorheological liquid, and its possible applications in a magnetically controlled display layer. Also, electromagnets are used instead of conventional neodymium magnets. Variations in the coil shape and base shape are also explored. The aim is to achieve dimensions closer to existing mechanical braille systems. The models considered are analysed on COMSOL Multiphysics software [3]. Considerable improvement is achieved in reducing size to improve resolution. There is vast scope for further research in improving the system for commercial viability.

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2013

S. .S and Dr. Thirumalini S., “Performance Evaluation of a Single Cylinder Diesel Engine with LM6 Alloy Coated Piston Crown using Micro-Arc Oxidation Process”, in ICIESMS 2013, Vickram College of Engineering, Madurai, 2013.

2013

R. Sundararajan, Dr. Thirumalini S., Ramamoorthy, B., and Natarajasundaram, B., “Steering Kickback Dminution on EHPS for Enhancing Vehicle Ride Comfort and Handling”, in SAE International, 8th SAE India International Mobility and Commercial Vehicle Engineering Congress (SIMCOMVEC), Chennai, Chennai, 2013.[Abstract]


Electro-Hydraulic Power Steering (EHPS) system is used in modern vehicles to effect reduction in fuel consumption rate and steering effort. The mechanical linkages between the steering wheel and tire, transfers road shocks to steering wheel as high amplitude vibration. This high amplitude vibration causes the steering wheel to deviate from driver intended position. This phenomenon is called steering kickback. The initial objective is to reduce the steering kickback with minimum changes in the vehicle systems. Using check valve is one of the inexpensive and easy operational counter measures. Vehicle level tests were done to evaluate the countermeasure and it was found to have approximately 55 % reduction in kickback. Multi Body Dynamics (MBD) simulation is done using ADAMS/Car to establish the vehicle parameters involve in steering kickback. Full car model was simulated using the experimental conditions and validated. Finally from the simulation, optimized vehicle parameters are identified to reduce the steering kickback. More »»

2012

P. Vishnu, Ajaykrishna, R., and Dr. Thirumalini S., “Cost effective energy solution with dual battery for plug-in hybrid electric vehicle (PHEV) in a public transportation system”, in Proceedings of the 2012 7th IEEE Conference on Industrial Electronics and Applications, ICIEA 2012, Singapore, 2012, pp. 1555-1560.[Abstract]


This paper proposes a novel method to find an effective solution for reducing the effect of environmental pollution through an efficient eco-friendly mode of public transport system. In the proposed topology a combination of dual battery powered plug-in hybrid electric vehicle (PHEV), optimizes the utilization of energy sources depending upon the vehicle riding conditions. Deep cycle NiMH battery power for steady speed driving conditions and starter lead acid battery for vehicle starting is used to significantly reduce the cost of installation as well as operation of a PHEV bus. Using series hybrid powertrain, the dependency on gasoline is minimized and hence will reduce the pollution rates drastically. Fast charging technique takes it less time than a conventional PHEV taking long hours of charging. Swappable batteries with dedicated swapping stations provide proper maintenance of battery, thus improving the battery parameters required for operating a public transport system which would be a present-day cost efficient alternative to the modern hybrid buses. © 2012 IEEE.

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2011

J. Janardhanan, Telsang, G., and Dr. Thirumalini S., “Experimental Investigations on Laser Weldability for different Stainless Steel”, in 2nd International Conference on Simulation, Modeling and Analysis, Amrita School of Engineering, Coimbatore, National institute of Technology, Calicut, NAFEMS – INDIA, 2011.

Publication Type: Conference Proceedings

Year of Publication Title

2016

M. Abilash, Senthilkumar D., Padmanabham, G., ,, Dr. Padmanaban R., and Dr. Thirumalini S., “The effect of welding direction in CO 2 LASER - MIG hybrid welding of mild steel plates”, IOP Conference Series: Materials Science and Engineering, vol. 149. p. 012031, 2016.[Abstract]


In this paper, hybrid laser-arc welding process has been studied based on the relative position of the laser and the arc (i.e. laser-leading and arc-leading arrangement) and, the effects of welding parameters, such as the laser power, arc current, arc voltage and the welding speed on the weld bead were investigated. The study indicates that the welding direction has a significant effect on the weld bead and weld pool behaviour. The result shows that laserleading configuration shows better bead characteristics when compared to arc-leading configuration. This is because in the laser-leading case molten metal flow is inward, while in the arc-leading case the metal flow is outward leading to variation in solidification front resulting in lack of synergic effects of both processes.

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2016

Vaira Vignesh R., Dr. Padmanaban R., Arivarasu, M., Dr. Thirumalini S., Dr. Gokulachandran J., and Ram, M. Sesha Saty, “Numerical modelling of thermal phenomenon in friction stir welding of aluminum plates”, IOP Conference Series: Materials Science and Engineering, vol. 149. p. 012208, 2016.[Abstract]


Friction stir welding (FSW) is a solid state welding process with potential to join materials that are non weldable by conventional fusion welding techniques. The study of heat transfer in FSW aids in the identification of defects like flash, inadequate heat input, poor material flow and mixing etc. In this paper, transient temperature distribution during FSW of aluminum alloy AA6061-T6 was simulated using finite element modelling. The model was used to predict the peak temperature and analyse the thermal history during FSW. The effect of process parameters namely tool rotation speed, tool traverse speed (welding speed), shoulder diameter and pin diameter of tool on the temperature distribution was investigated using two level factorial design. The model results were validated using the experimental results from the published literature. It was found that peak temperature was directly proportional to tool rotation speed and shoulder diameter and inversely proportional to tool traverse speed. The effect of pin diameter on peak temperature was found to be trivial.

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