Combustion and Propulsion Laboratory

Research Interests

The main focus of our research group is to do fundamental as well as applied research in the areas of combustion and propulsion. Our group will mainly focus on the following research areas:

Futuristic Propulsion Technologies Including High-speed Propulsion Systems and Detonation-based Engines
Supersonic and Hypersonic Propulsion Systems
Supersonic Combustion
Detonation and Explosion Physics
Gas Turbine Combustion Including Emissions
Flame Spread and Fire Dynamics
Soot Formation and Oxidation
Combustion Generated Functional Nanoparticles
Chemical Kinetics (Jet Fuel, Biofuel and Liquid Hydrocarbon Fuel Combustion Chemistry, Green Fuels)
Flame Synthesis (Carbon Nanotubes, Graphene, Quantum Dots, Nanomedicine, etc.)
Renewable and Sustainable Energy
Computational Fluid Dynamics (CFD)

Publications

Ongoing Research Projects

Outreach

Professional Memberships

My Academic Family Tree

High-speed Propulsion Systems Including Detonation-based Engines

The power of detonations has been well recognized. In principle, detonations are efficient means of burning a fuel-air mixture, releasing its chemical energy and converting the resulting enthalpy to work. Detonation cycles are based on the concept of Pressure Gain Combustion (PGC). In PGC, the combustion process is close to constant volume, which can be used to augment cycle output and/or reduce engine size. In comparison, typical gas turbines burn at constant pressure. Under comparable conditions, the detonation cycle provides a burned gas with lower entropy and potentially higher work output. Utilizing detonations as a means of energy conversion is, however, not quite straightforward. Complications arise from difficulties associated with rapid mixing of fuel and air to initiating and sustaining a detonation in a controlled manner. Many factors impact a sustained detonation. Our research group will address the problems associated with the initiation and sustainment of the detonation waves in small propulsion devices. Numerical data will be compared against the experimental data for numerical model development and validation.

Detonation and Explosion Physics

Our research group also focuses on understanding the physics of detonations and explosions. The applications range from utilizing detonations for as a source of power for detonation-based engines to averting dangers associated with accidental explosions. Since explosions and detonations can occur in process industries, chemical processing plants, oil storage depots, nuclear reactors, etc. it is essential to understand the mechanisms and conditions under which they undergo explosion and detonation. Our research group primarily focuses on the inhibition mechanisms of a more violent form of combustion such as detonation and explosion and to use the generated knowledge to propose necessary safety norms associated with such accidents. The main goal of the reserach program is to provide vital insights into the likelihood and reality of detonations and explosions involving flammable gas leaks. As such, it will serve as the foundation for improving risk management in the oil and gas industry and will create a framework on which to base worker safety regulations. We also focus on the controlled use of detonations for futuristic propulsion systems.

Soot Formation and Oxidation

Soot is a major source of particulate air pollutants. Its emission sources include diesel and aircraft engines. Particulate soot has been linked to increased mortality and mobility rates and a range of long-term health effects. Ambient aerosols resulting from particulate soot emission also impact the global climate in a manner that is yet to be fully understood. In general, the impact of soot emission is determined largely by the particle size distribution and the chemical composition. In combustion engines, the mechanism and kinetics of soot formation remain to be an unresolved scientific problem. The major scientific challenges include a lack of ability to probe the chemical composition and size/mass changes during the growth process of nascent soot in a time-resolved manner. Apart from this, the formation of nascent soot during incomplete combustion of hydrocarbon fuels has remained one of the least solved problems of combustion.

Combustion Generated Functional Nanoparticles

Nanoparticle synthesis by aerosol or flame processes is a promising method for the manufacture of new functional materials and devices. Compared to wet chemistry approaches (e.g., sol–gel), aerosol processing is scalable and can produce materials with high purity and quality. Nanostructured materials have fascinating applications that range from medicine, medical diagnostics, heterogeneous catalysis, microelectronics, to clean energy conversion.

Flame Spread and Fire Dynamics

Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve complex interactions at the interface between gas-phase flames and condensed-phase fuels. This interaction is even more complex as scales increase because realistic boundary layer diffusion flames occur under fully turbulent conditions which have yet to be fully replicated or understood at the bench scale, where detailed measurements can be conducted. This lack of knowledge has become apparent in, for instance, flame spread modeling of wildland and wall fires and solid propellant combustion in hybrid rocket motors, which occur under highly turbulent conditions and yet have to incorporate the burning of realistic fuels or local turbulent combustion behavior. This experimental research program will explore the dynamic relationship between combustible solids and gas-phase flames in turbulent boundary layers, thus expanding the applicability of the theoretical model proposed earlier for laminar flames to realistic large-scale turbulent flames present in almost all unwanted fires, hybrid rocket motors, and other similar combustion phenomena. The theoretical model will be revised to include the radiation effects and comprehensive testing for the same will be accomplished in both the numerical and experimental setting. The field of combustion in boundary layers over and through fuel beds also presents a rich field of exploration, related to both material flammability and flame spread. Studying the dynamic coupling between reacting solids and gas-phase turbulent reacting flows will also be studied. Subsequently, the theoretical model will be expanded to predict the burning behavior of large-scale turbulent fires.

Chemical Kinetics for Combustion Chemistry

Jet Fuel, Biofuel, and Liquid Hydrocarbon Fuel Combustion Chemistry
Detonation and Explosion Kinetics

Our research group also specializes in the chemical kinetics study of jet fuels, biofuels, liquid hydrocarbon fuels and gaseous fuels. Our group also studies the detonation and explosion kinetics of various fuel-oxidizer detonating mixtures. Our group also specializes in the chemical kinetic modelling of flame-synthesized functional nanoparticles as well as the kinetic modelling of soot formation and oxidation in flames. Our group also investigates the kinetics of halogenated compounds or flame inhibitors for the suppression of a given flame and fire. We also investigate the inhibition mechanisms of a more violent form of combustion such as detonation or explosion.