Dr. Varunkumar, S.

Associate Professorvaruns

Office Room No : 206-B, Thermodynamics & Combustion Engineering Lab
Tel: (O) : +91 44 2257 4717
Email : varuns (append @iitm.ac.in)

See lab webpage to know about our research – TDCE_lab

NPTEL-SWAYAM course on ‘Fundamentals of Combustion for Propulsion’ starting in Jan, 2022

Interested in joining for MS/PhD – check out https://research.iitm.ac.in/

For PhD positions through PMRF check eligibility and other details here – https://may2020.pmrf.in/


Dr. S Varunkumar received his B.Tech in Mechanical Engineering from NIT, Trichy in 2007 and PhD from Indian Institute of Science, Bangalore, in 2012. He worked as a research associate at IISc from February, 2012 to May, 2013 and as Assistant professor (on contract) till December, 2013 at IIT Ropar, Punjab, before joining IIT Madras as Assistant Professor.

Research interests

Past research areas:

  1. Gasification and combustion of biomass and coal.
  2. Composite solid propellant combustion modeling.
  3. Modeling combustion driven instabilities in solid propellant rockets.


Currently exploring:

  1. High frequency combustion instabilities in liquid propellant rockets and afterburners.
  2. Catalytic fast pyrolysis of biomass for liquid fuel synthesis.
  3. Application of symbolic regression and other data-driven methods to problems in, but not limited to, combustion and fluid mechanics.

Awards & Honors

  1. Prof. Chintakindi V Joga Rao Medal from IISc, Bangalore for best thesis in Aerospace Engineering for the year 2012 – 2013


Selected Publications (Google scholar profile)

Journal publications

  1. Mani Kalyani Ambatipudi & Varunkumar S (2020) Experimental and Theoretical Investigations on High-ash Coal-air Flames in High-speed Jets Stabilized Recirculating Flow, Combustion Science and Technology, DOI: 10.1080/00102202.2020.1799202
  2. Jaganathan V M, Mani Kalyani Ambatipudi & Varunkumar S (2020) The Phenomenon of Flame Jump in Counter–current Flame Propagation in Biomass Packed Beds – Experiments and Theory, Combustion Science and Technology, DOI: 10.1080/00102202.2020.1804886
  3. Jaganathan, V. M., and S. Varunkumar. “A novel self-sustained single step process for synthesizing activated char from ligno-cellulosic biomass.” Fuel Processing Technology 208 (2020): 106516.
  4. Ambatipudi Mani Kalyani, Jaganathan V. M. & Varunkumar S. “Mechanisms governing the gasification to char oxidation transition in counter-current flame propagation in packed beds: insights from single-particle experiments”. Particulate Science and Technology (2020): DOI:10.1080/02726351.2020.1767245
  5. Wadhai, Vishal, and S. Varunkumar. “Perturbation analysis of the Heterogeneous Quasi 1-D model–a theoretical framework for predicting frequency response of AP–HTPB composite solid propellants.” Combustion Theory and Modelling (2020): 1-20.
  6. Ali, S. M., and S. Varunkumar. “Effect of burner diameter and diluents on the extinction strain rate of syngas-air non-premixed Tsuji-type flames.” International Journal of Hydrogen Energy (2020).
  7. V.M. Jaganathan, Omex Mohan, S. Varunkumar, Intrinsic hydrogen yield from gasification of biomass with oxy-steam mixtures. International Journal of Hydrogen Energy 44, Issue 33, (2019):17781-17791.
  8. V M Jaganathan and S Varunkumar. Net carbon-di-oxide conversion and other novel features of packed bed biomass gasification with O2/CO2 mixtures. Fuel 244 (2019): 545-558.
  9. S Varunkumar and H. S. Mukunda. Aluminized composite propellant combustion modeling with Heterogeneous Quasi-One dimensional (HeQu1-D) approach. Combustion and Flame 192 (2018): 59-70.
  10. S. Varunkumar, M. Zaved, H.S. Mukunda. A novel approach to composite propellant combustion modeling with a new Heterogeneous Quasi One-dimensional (HeQu1-D) framework, Combustion and Flame, Volume 173, November 2016, Pages 411-424. (link to MATLAB code for HeQu1-D).
  11. S Varunkumar, N K S Rajan, and H S Mukunda. Experimental and computational studies on a gasifier based stove. Energy Conversion and Management, 53(1):135-141, 2012.
  12. S Varunkumar, N K S Rajan, and H S Mukunda. Universal flame propagation behaviour in a packed bed of biomass. Combustion Science and Technology. 185 (8):1241-1260, 2013.
  13. S Varunkumar, N K S Rajan and H S Mukunda. Single particle and packed bed combustion in modern gasifier stoves -density effects. Combustion Science and Technology, 183(11):1147-1163, 2011.


International conference proceedings

  1. Arvind Iyer, Balamurali N R, and Varunkumar S. Random packing of multi-modal spheres in a cubic box – a model for understanding AP/HTPB based composite solid propellants. International Autumn Seminar on Propellants, Explosives and Pyrotechnics, Shandong Province, China. September 2015.
  2.  Ajey N and Varunkumar S. Coupled Dimensional analysis and Computational Fluid Dynamics Approach to Design of alpha-type Stirling Engines. Proceedings of 17th International Stirling Engine Conference, August, 2016, Northurmbria University, UK
  3. Jaganathan V M, Kalyani A M and Varunkumar S. Unified igntion – de-volatalization model fixed bed biomass gasification/combustion. 11th European Conference on Industrial Furnaces and Boilers, Portugal, April, 2017.
  4. Ali S.M and Varunkumar S. On the extinction strain rates of counter-flow diffusion flames. 11th ASPACC, Sydney, December, 2017.
  5. Vishal Wadhai and Varunkumar S. Linear instability and DC shift in tactical missile solid rocket motors – a computational study. 11th ASPACC, Sydney, December, 2017.
  6. Ali S.M and Varunkumar S. Preliminary results on syngas kinetic mechanism optimization using the new Opt-D* algorithm. 11th International Conference on Chemical Kinetics, Orleans, June, 2019.


National Conferences

  1. S Varunkumar, V M Jaganathan and N Ajey. Application of Universal Flame Propagation Behaviour in Biomass Packed Bed to Design of Grate Furnaces. NCICEC, Dehradun. November, 2015.



  1. S Varunkumar. Open issues in soot modeling. July, 2016.


Student guidance

  1. M Zaved (MS) – Heterogeneous quasi one dimensional model for steady state combustion of AP/HTPB based composite propellants (pdf).
  2. N Ajey (MS) – Experimental and computational studies on an alpha type Stirling engine for combined heat and power applications (pdf).
  3. Vishal Wadhai (MS) – Unsteady heterogeneous quasi 1-D combustion model for AP-HTPB based composite propellant (pdf)


My reading list