Research Projects

Rotating Detonation Engines (RDE) are the next step in the evolution of energy-efficient internal combustion engines. While gaseous fuel-based RDEs have been tested in the past, currently, there is a strong interest in the development of liquid-fueled RDEs worldwide due to the higher energy density of liquid fuels, safety, and practicality. In liquid-fueled RDEs, one or more detonation waves azimuthally propagate around an annular combustion chamber. Liquid fuel droplets and compressed air are injected from the base of this annular combustion chamber. The rotating detonation waves ignite the injected fuel. The energy released from the combustion of the fuel droplet strengthens the rotating detonation wave as it continues to traverse the annular space. The high enthalpy gas produced is expelled from the open end of the combustion chamber either through an aerospike nozzle to generate thrust or through a gas turbine to extract work. Therefore, the energy output and efficiency of a liquid-fueled RDE depends on the detonation wave-driven combustion of the liquid fuel droplets. Knowledge of shock and detonation wave interactions with fuel droplets is essential for developing practical RDEs. Secondary atomization, vaporization, and combustion of the fuel droplets due to interaction with detonation and strong shock waves must be characterized to predict the energy released through the combustion of the fuel droplets and consequently, the thrust produced by the engine. The pressure, temperature, and velocity of detonation waves traversing through multiphase mixtures of air and fuel droplets must be determined to predict and control the stability and strength of the detonation waves propagating in the combustion chamber. Currently, there is no accurate theory to predict the Chapman-Jouguet (CJ) pressure and velocity of a detonation in a heterogeneous multiphase mixture of air and liquid droplets. However, studying detonation wave-induced combustion of fuel droplets and measuring CJ states through experiments is challenging and prohibitively expensive. Here we propose to develop a high-resolution 3D computational fluid dynamics model to study shock and detonation wave-induced fuel droplet combustion in an RDE environment. The droplet interfaces will be resolved to capture droplet break-up, vaporization, and flame structure around the droplets due to the interaction with an incoming shock and detonation wave. High-resolution calculations of reacting droplet clusters will be performed to study the effect of multiphase heterogeneities on the dynamics of the detonation waves. Such computations of droplet combustion in detonation environments are being performed for the first time. The simulation-derived data will be used to derive models of drag coefficient, Nusselt number, and Sherwood number correlations for droplets in detonation environments. These surrogate models will be useful in the design and optimization of RDEs through engine-scale simulations.