Qualification: 
Ph.D, M.Tech, BE
h_mohan@blr.amrita.edu
Phone: 
9930085839

Dr. Hari Mohan Kushwaha currently serves as Assistant Professor at the Department of Mechanical Engineering, School of Engineering, Amrita Vishwa Vidyapeetham, Bengaluru.

Dr. Hari Mohan joined the Department of Mechanical Engineering as Assistant Professor. He holds Ph.D. in Mechanical Engineering from Indian Institute of Technology Indore, Madhya Pradesh; MTech. in Mechanical Engineering with specialization in Thermal Engineering from Indian Institute of Technology Roorkee, Uttarakhand and B.E in production and Industrial Engineering from Govt. Engineering College Kota, University of Rajasthan Jaipur, India. He has authored more than fifteen research papers in International Journals and Conferences/Proceedings. He has five years of teaching experience, and three years of research experience as a Post-Doctoral Fellow at IIT Bombay prior joining Amrita. His main areas of research are in microscale heat transfer, rarefied gas flows, and modeling and simulation. He is serving as reviewer of various International (peer reviewed) Journals

Education

  • 2016: Ph. D. Mechanical Engineering
    Indian Institute of Technology Indore (MP) India
  • 2010: M.Tech Mechanical Engineering
    Indian Institute of Technology Roorkee (UK) India
  • 2003: B.E. Mechanical Engineering
    Govt. Engineering College Kota, University of Rajasthan, Jaipur, (RJ) India

Publications

Publication Type: Book

Year of Publication Title

2020

A. Agrawal, Jadhav, R. Sudam, and Dr. Hari Mohan Kushwaha, Microscale Flow and Heat Transfer: Mathematical Modelling and Flow Physics. 2020.[Abstract]


This book covers concepts and the latest developments on microscale flow and heat transfer phenomena involving a gas. The book is organised in two parts: the first part focuses on the fluid flow and heat transfer characteristics of gaseous slip flows. The second part presents modelling of such flows using higher-order continuum transport equations.

The Navier-Stokes equations based solution is provided to various problems in the slip regime. Several interesting characteristics of slip flows along with useful empirical correlations are documented in the first part of the book. The examples bring out the failure of the conventional equations to adequately describe various phenomena at the microscale. Thereby the readers are introduced to higher order continuum transport (Burnett and Grad) equations, which can potentially overcome these limitations. A clear and easy to follow step by step derivation of the Burnett and Grad equations (superset of the Navier-Stokes equations) is provided in the second part of the book. Analytical solution of these equations, the latest developments in the field, along with scope for future work in this area are also brought out.

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Publication Type: Book Chapter

Year of Publication Title

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Microscale Flows”, in Microscale Flow and Heat Transfer, pp.25-80, 2020, pp. 25-80.

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Overview to Numerical and Experimental Techniques”, in Microscale Flow and Heat Transfer, pp.305-312, 2020, pp. 305-312.[Abstract]


In the previous chapters, the governing equation and analytical solution of the equation was presented for flows in relatively simple geometries. However, problems encountered in most practical situations are much more difficult, involving complex geometry, unclear boundary conditions, transition from one flow regime to another, and other complications. Obtaining an analytical solution in these cases is virtually not possible. One therefore resorts to either numerical methods for solution of the governing equation or experiments. In this chapter, we briefly comment on these techniques, while details can be found in specialized books and papers on the subject. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Alternate Forms of Burnett and Grad Equations”, in Microscale Flow and Heat Transfer, pp.259-304, 2020, pp. 259-304.[Abstract]


In the previous two chapters, a formal derivation of the Burnett and Grad equations was presented. The derivation involved several novel ideas making the approach and the obtained equations invaluable. However, as reviewed in this chapter, both these equations have several limitations because of which working with alternate forms of these equations becomes necessary. Therefore, several variants of these equations have been proposed in the literature. The basic idea behind fixing the equations and the available variants are introduced in this chapter. Comparison of the results as obtained from the variants of the equations for a few specific cases is also presented. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Summary and Future Research Directions”, in Microscale Flow and Heat Transfer, pp.313-315, 2020, pp. 313-315.[Abstract]


In the various chapters of this book, we have covered several different aspects of gas flow and heat transfer in the slip and transition regimes. In this last chapter, we present a broad summary of what is well understood and what remains to be better explored. We also identify some important research problems which can help in further development of this subject. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Burnett Equations: Derivation and Analysis”, in Microscale Flow and Heat Transfer, pp.125-188, 2020, pp. 125-188.[Abstract]


The Burnett equations is a superset of the Navier–Stokes equations, and one of the most important higher-order continuum transport equations. The derivation and nature of the equation in both Cartesian and cylindrical coordinates is presented in this chapter. The equations involve large number of terms, which makes them quite formidable to solve, both analytically and numerically. Nonetheless there has been some recent success in obtaining analytical solution of the Burnett equations, as discussed here. An order of magnitude analysis of the various terms reveals that the Burnett-order terms in the equations are of order Knudsen number square. A stability analysis of the equations for one-dimensional wave reveals the unstable nature of the equations. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Grad Equations: Derivation and Analysis”, in Microscale Flow and Heat Transfer, pp.189-258, 2020, pp. 189-258.[Abstract]


In certain physical problems, the Navier–Stokes equations are insufficient to describe the flow physics accurately, making it necessary to take recourse to higher order continuum transport equations. Grad pioneered the moment method by which successive approximations of the microscopic Boltzmann equation can be obtained. Grad proposed to expand the particle distribution function f(c, x, t) in terms of orthogonal Hermite polynomials, with an infinite set of Hermite coefficients being equivalent to the particle distribution function f itself. The number of Hermite coefficients to be considered in the expansion depends upon the degree of accuracy desired. The first few Hermite coefficients are the state variables, stress tensor, and heat flux vector. These variables are not expressed in terms of other thermodynamic variables but are on par with them, and satisfy their own differential equation. This distinct approach of Grad along with the resulting equations is expounded in this chapter. The linearized form of the Grad equations is applied to two practical problems and the obtained solutions are compared against that obtained through the Navier–Stokes equations. The Grad equations can be used to obtain the Navier–Stokes equations and Cattaneo’s equation as discussed here. The differences as well as the similarities between the Grad approach and the Chapman–Enskog approach (introduced in Chap. 5) are also brought forward. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Microscale Heat Transfer”, in Microscale Flow and Heat Transfer, pp.81-113, 2020, pp. 81-113.[Abstract]


In this chapter, we present the fundamental aspects of microscale heat transfer for gas flow through different geometries. Such a study is motivated by interest in cooling of electronic components, energy conversion devices, and other MEMS and bio-medical applications. The heat transfer at microscale is different than that of macroscale primarily due to the presence of velocity slip and temperature jump at the wall. The physics pertinent to microscale heat transfer is reasonably complex and solutions of various simplified models are available in the literature. Here we confine our presentation to the slip flow regime for flow through three configurations: parallel plates, microtube, and micro-annulus. We also briefly discuss the effect of other complicating factors and comment on comparison with experiments. A discussion on Knudsen pump and useful empirical correlations are also provided. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Need for Looking Beyond the Navier–Stokes Equations”, in Microscale Flow and Heat Transfer, pp.115-123, 2020, pp. 115-123.[Abstract]


The need for looking beyond the Navier–Stokes equations is addressed in this chapter through specific examples where these equations fail. We also examine some extensions of the Navier–Stokes equations, which have been recently proposed in the literature. Similarly, attempts to modify the Fourier law to account for non-Fourier effects are reviewed. An example of shock wave where these alternative forms of Navier–Stokes equations have been applied is also included. More »»

2020

A. Agrawal, Dr. Hari Mohan Kushwaha, and Jadhav, R., “Introduction to Microscale Flows and Mathematical Modelling”, in Microscale Flow and Heat Transfer (pp.1-23), 2020, pp. 1-23.[Abstract]


The purpose of this book is to understand fluid flow and heat transfer at the microscale. The focus is on gases, as the mean free path of the gas can become comparable to the passage dimensions, and an additional non-dimensional number (Knudsen number) starts affecting the dynamics of the flow and heat transfer behavior. The effect of Knudsen number turns out to be non-trivial, as it not only leads to several new physical phenomena, but also exposes the limitations of the celebrated Navier–Stokes equations in modelling such flows. The second major purpose of this book is therefore to examine equations which can model such high Knudsen number flows. Again, we first show that simple modifications to the Navier–Stokes equations and boundary conditions are not sufficient to fulfill this objective. There is perhaps no alternative but to shun the conventional way of deriving transport equations, and resort to the Boltzmann equation for derivation of “higher-order continuum transport equations.” The book presents a clear derivation of the Burnett and Grad equations starting from the Boltzmann equation, a discussion on the variants of the Burnett and Grad equations, and some known solutions of these higher-order continuum transport equations. More »»

2017

Dr. Hari Mohan Kushwaha and Dr. Santosh Kumar Sahu, “Analysis of Heat Transfer in the Slip Flow Region Between Parallel Plates”, in Lecture Notes in Mechanical Engineering, 2017, pp. 1331-1339.[Abstract]


In this paper, an analytical study has been carried out to investigate the effect of viscous dissipation on heat transfer characteristics in the slip regime for the fluid flowing between two infinite fixed parallel plates. The flow is assumed to be hydrodynamically and thermally fully developed with constant properties. In the present analysis, one wall is considered as adiabatic and the other one is kept at constant heat flux. Closed form expressions are accomplished for the Nusselt number as a function of Knudsen number and Brinkman number. The limiting condition of the present prediction for Kn = 0, Kn 2 = 0, and Br = 0 is presented to verify the results. More »»

Publication Type: Conference Proceedings

Year of Publication Title

2018

Dr. Hari Mohan Kushwaha and Agrawal, A., “Analysis of gas flow through micro-annulus using second order velocity slip and temperature jump”, Proceedings of 7th International and 45th National conference on Fluid Mechanics and Fluid Power. IIT Bombay, (MH) India, 2018.

2018

Dr. Hari Mohan Kushwaha and Agrawal, A., “Heat transfer of gaseous flow through micro-annulus in slip regime”, ThermaComp. IISC Bangalore, 2018.

2015

Dr. Hari Mohan Kushwaha, “Analysis of slip flow heat transfer between two unsymmetrically heated parallel plates with viscous dissipation”, ICFDT 2015: XIII International Conference on Fluid Dynamics and Thermodynamics. Wembley, London, UK, 2015.[Abstract]


This paper presents an analytical investigation to study the heat transfer and fluid flow characteristics in the slip flow region for hydrodynamically and thermally fully developed flow between parallel plates. Both upper and lower plates are subjected to asymmetric heat flux boundary conditions. The effect of first order velocity slip, temperature jump, asymmetric heat flux ratio and viscous dissipation on the heat transfer performance is analyzed. Closed form expressions are obtained for the temperature distribution and Nusselt number. Present predictions are verified for the cases that neglect the viscous heating and microscale effects. The effect of asymmetric heat flux ratio with and without viscous dissipation on Nusselt number for both macroscale and microscale is highlighted. The heat transfer characteristics are found to depend on various modeling parameters, namely, modified Brinkman number, Knudsen number and heat flux ratio.

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2014

Dr. Hari Mohan Kushwaha and Sahu, S., “Analysis of Heat Transfer in the Slip Flow Region Between Parallel Plates”, 5 th International and 41st National Conference on Fluid Mechanics and Fluid Power. IIT Kanpur, U.P., India, 2014.[Abstract]


In this paper, an analytical study has been carried out to investi-gate the effect of viscous dissipation on heat transfer characteristics in the slip regime for the fluid flowing between two infinite fixed parallel plates. The flow is assumed to be hydrodynamically and thermally fully developed with constant properties. In this analysis, one wall is considered as adiabatic and the other one is kept at constant heat flux. Closed form expressions are accomplished for the Nusselt number as a function of Knudsen number and Brinkman number. The limiting condition of the present prediction for Kn = 0, Kn 2 = 0, and Br = 0 is presented to verify the results.

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2013

Dr. Hari Mohan Kushwaha, Sahu, S. K., and Verma, A. K., “Analysis of slip flow heat transfer between parallel plates with constant heat flux boundary conditions”, 11th ISHMT-ASME and 21st National Heat and Mass Transfer International Conference. IIT Kharagpur, India, 2013.

2013

Dr. Hari Mohan Kushwaha and Sahu, S. K., “Analysis of second order slip flow heat transfer in a microtube”, 11th International ISHMT-ASME and 21st National Heat and Mass Transfer International Conference. IIT Kharagpur, India, 2013.

2013

S. K. Sahu and Dr. Hari Mohan Kushwaha, “Analysis of microscale forced convection heat transfer in a microtube”, The Recent Advances in Mechanical Engineering. Uttarakhand, India, 2013.

Publication Type: Journal Article

Year of Publication Title

2016

Dr. Hari Mohan Kushwaha, Raj, P. Bharavath, and Sahu, S. K., “Heat transfer analysis of small scale gaseous flows in slip flow region”, Proceedings of 6th International and 43rd National Conference on Fluid Mechanics and Fluid Power, 2016.

2016

Dr. Hari Mohan Kushwaha and Sahu, S. K., “Analysis of slip flow heat transfer between two unsymmetrically heated parallel plates with viscous dissipation”, Sadhana, vol. 41, no. 6, pp. 653–666, 2016.[Abstract]


This paper presents an analytical investigation to study the heat transfer and fluid flow characteristics in the slip flow region for hydrodynamically and thermally fully developed flow between parallel plates. Both upper and lower plates are subjected to asymmetric heat flux boundary conditions. The effect of first order velocity slip, temperature jump, asymmetric heat flux ratio and viscous dissipation on the heat transfer performance is analyzed. Closed form expressions are obtained for the temperature distribution and Nusselt number. Present predictions are verified for the cases that neglect the viscous heating and microscale effects. The effect of asymmetric heat flux ratio with and without viscous dissipation on Nusselt number for both macroscale and microscale is highlighted. The heat transfer characteristics are found to depend on various modeling parameters, namely, modified Brinkman number, Knudsen number and heat flux ratio.

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2016

Dr. Hari Mohan Kushwaha and Dr. Santosh Kumar Sahu, “Comprehensive Analysis of Convective Heat Transfer in Parallel Plate Microchannel with Viscous Dissipation and Constant Heat Flux Boundary Conditions”, Journal of The Institution of Engineers (India): Series C, vol. 98, pp. 553–566, 2016.[Abstract]


This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, forced convective heat transfer characteristics of gaseous flows through a parallel plate microchannel with different constant heat flux boundary conditions. The first order velocity slip and viscous dissipation effects are considered in the analysis. Here, three different thermal boundary conditions such as: both plates kept at different constant heat fluxes, both plates kept at equal constant heat fluxes and one plate kept at constant heat flux and other one insulated are considered for the analysis. The deviation in Nusselt number between the model that considers both first order velocity slip and temperature jump and the one that considers only velocity slip is reported. Also, the effect of various heat flux ratios on the Nusselt number is reported in this analysis. In addition, the deviation in Nusselt number between first and second order slip model is discussed in this study.

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2016

Dr. Hari Mohan Kushwaha, Selvakumar, P. Bharvath R., and Dr. Santosh Kumar Sahu, “Effect of Shear Work on the Heat Transfer Characteristics of Gaseous Flows in Microchannels”, Chemical Engineering & Technology, vol. 40, no. 1, pp. 103–115, 2016.[Abstract]


The effect of shear work at solid boundaries for parallel plates and a micropipe is considered to analyze the heat transfer characteristics in the slip flow region for gaseous flow. The fluid flow is assumed to be laminar, incompressible, steady, and hydrodynamically and thermally fully developed. The effects of second‐order velocity slip, temperature jump, shear work at the solid surface, and viscous dissipation are considered. The constant heat flux boundary condition is used at the surface of the parallel plates and of the micropipe. Closed‐form expressions are obtained for the temperature distribution and Nusselt number as a function of various modeling parameters for both geometries. The results show that neglecting the shear work underpredicts the Nusselt number.

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2015

S. K. Sahu and Dr. Hari Mohan Kushwaha, “Effect of viscous dissipation and rarefaction on parallel plates with constant heat flux boundary conditions”, Chemical Engineering and Technology , pp. 235-245, 2015.

2014

Dr. Hari Mohan Kushwaha and Sahu, S. K., “Analysis of Gaseous Flow Between Parallel Plates by Second- Order Velocity Slip and Temperature Jump Boundary Conditions”, Heat Transfer—Asian Research, vol. 43, pp. 734-748, 2014.[Abstract]


Abstract In this study the momentum and energy equations are solved to analyze the flow between two parallel plates by employing second-order velocity slip and temperature jump conditions. The flow is considered to be laminar, incompressible, hydrodynamically/thermally fully developed, and steady state. In addition to the isoflux condition, viscous dissipation is included in the analysis. Closed form expressions for the temperature field and Nusselt number are obtained as a function of the Knudsen number and Brinkman number. The Nusselt number obtained by employing the second-order model is found to be lower compared to the continuum value and agrees well with the other theoretical models. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21116

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2014

Dr. Hari Mohan Kushwaha, “Analysis of gaseous flow in a micropipe with second order velocity slip and temperature jump boundary conditions”, Heat and Mass Transfer, vol. 50, 2014.[Abstract]


In this paper, second order velocity slip and temperature jump boundary conditions are used to solve the momentum and energy equations along with isoflux thermal boundary condition at the surface of the micropipe. The flow is assumed to be hydrodynamically and thermally fully developed inside the micropipe and viscous dissipation is included in the analysis. The solution yields closed form expressions for the temperature field and Nusselt number (Nu) as a function of various modeling parameters, namely, Knudsen number and Brinkman number (Br). For the given values of Br, the maximum difference of Nu between continuum flow with first order slip model and continuum and, second order slip model is found to be 35.67 and 34.62 %, respectively. Present solution exhibits good agreement with the other theoretical models. More »»

2014

Dr. Hari Mohan Kushwaha and Dr. Santosh Kumar Sahu, “Effects of Viscous Dissipation and Rarefaction on Parallel Plates with Constant Heat Flux Boundary Conditions”, Chemical Engineering & Technology, vol. 38, 2014.[Abstract]


The effect of viscous dissipation and rarefaction on heat transfer characteristics of hydrodynamically and thermally fully developed flow between parallel plates with constant heat flux conditions is analyzed. Three different types of heat flux boundary conditions, i.e., both plates kept at different constant heat fluxes, both plates kept at equal constant heat fluxes, and one plate insulated, are applied. In all cases, closed form expressions are obtained for the temperature distribution and Nusselt number. Viscous dissipation, rarefaction, and heat flux ratio are found to influence the heat transfer substantially. The present predictions are verified for the cases which neglect the microscale and viscous heating effect. The obtained results are in good agreement with other analytical results. More »»