Current Projects

Computational modeling of turbulent reacting spray flows

  • Unburned hydrocarbon (UHC) emissions under low-temperature combustion (LTC) operating conditions are linked to the end-of-injection transient in diesel injectors and the impact of this transient on the combustion of near-nozzle mixtures.
  • Studied the combustion behavior after the end of injection to resolve “combustion recession” phenomenon that affects the emission of soot and unburned hydrocarbons in diesel engine.
  • Investigated the role of low-temperature chemistry in different reduced chemistry mechanism for diesel fuel surrogates in predicting combustion recession.


Computational & experimental study of  nucleation at near-critical conditions

  • The supercritical carbon dioxide Brayton cycle seeks to combine the primary advantages of the ideal Brayton Cycle by utilizing CO2 above its critical pressure. It is expected that due to pressure reduction, nucleation occurs at the end of the turbine blades and at the entrance of the compressor. The impact of the droplets formed due to nucleation with the turbine blades is of serious concern with respect to the operation and the material degradation.
  • Developed a computational set up for simulation of super-critical carbon dioxide nucleation near critical point in Brayton cycles used in supercritical energy cycles.
  • Performing experiments to study the nucleation phenomenon in a venturi system with super-critical carbon dioxide using high-speed camera.


Heat exchanger design and modeling for supercritical energy cycles

  • Printed Circuit Heat Exchanger (PCHE) design is one of the areas where the properties of s-CO2 pose many challenges yet could yield the greatest advantages for heat transfer between high-temperature fluids e.g., natural gas combustion products; molten salts and s-CO2 for electrical energy conversion in simple cycle gas turbines or in concentrated solar power systems (CSP).
  • Developed a computational set up for simulation of fluid/ solid interaction in printed circuit heat exchangers (PCHE) with super-critical carbon dioxide and molten halides as fluids, applicable to various designs and PCHE material in concentrated solar power (CSP) and nuclear systems.

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PhD Research

Direct numerical simulation of atomization of  round liquid jets at high pressure

  • The primary goal of my research was to resolve the size and distribution of droplets formed during the atomization process. The fuel droplet sizes influence the fuel evaporation and its mixing with air in combustion chamber and eventually determine the combustion efficiency and engine emission outcome.
  • Implemented an in-house multi-dimensional and transient CFD code with level-set method for tracking the interface of the two phase flow for simulating the behavior of a liquid jet injected into high-pressure air at diesel engine-like conditions during the start-up and shut-down portions of injection.
  • Studied the development of different types of spatial and temporal hydrodynamic instabilities at the liquid jet interface leading to formation of small-scale liquid protrusion, e.g. ligaments and droplet to resolve the primary atomization.
  • Developed a new less computationally intensive axisymmetric and 3D CFD model for simulating a small-segment of the jet instead of the full jet and studied the temporal development of the hydrodynamic instabilities with higher resolution in great details.

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Resolving the role of vorticity dynamics in atomization of round liquid jets

  • Studied the vorticity dynamics during primary liquid jet atomization via post-processing of the results obtained from the liquid-segment model and compared the vortex instability in single-phase liquid jets and 3D planar jets with 3D two-phase jet.
  • Identified the mechanisms responsible for promoting azimuthal instability, i.e. baroclinic effect vs. vortex stretching, vortex tilting, and viscous effects in liquid jet atomization and found the range of Re and We number, and density ratios that each mechanism dominated.