Qualification: 
Ph.D
Email: 
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 receive 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: Journal Article

Year of Publication Publication Type Title

2017

Journal Article

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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2017

Journal Article

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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2016

Journal Article

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 »»

2016

Journal Article

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

Journal Article

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

Journal Article

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 »»

2015

Journal Article

J. Koti 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, 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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2015

Journal Article

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.

2015

Journal Article

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.

2015

Journal Article

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. 19, pp. 37601-37604, 2015.

2015

Journal Article

S. Prabhakar.N, D, S., 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

Journal Article

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

Journal Article

J. James Cheeran, 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

Journal Article

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.

2014

Journal Article

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

Journal Article

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.

2012

Journal Article

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.

2012

Journal Article

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.

2009

Journal Article

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 Proceedings

Year of Publication Publication Type Title

2016

Conference Proceedings

V. R Vignesh, 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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2016

Conference Proceedings

M. Abilash, D kumar, S., 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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2014

Conference Proceedings

D. .Senthilkumar, .Ajaykrishna, R., and Dr. Thirumalini S., “Theoretical Analysis of Critical Design Parameters for Maximum Thermal Efficiency of Solar Stirling Engines”, The proceedings of International conference on Advances in Design and Manufacturing organized by National Institute of Technology. Tiruchirappalli, pp. PP1444-49, 2014.

Publication Type: Conference Paper

Year of Publication Publication Type Title

2013

Conference Paper

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 »»

2013

Conference Paper

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.

2012

Conference Paper

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

Conference Paper

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.

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