Ricerc@Sapienza

Nowadays Liquid Rocket Engines (LRE) represent a widespread technology in launcher applications. However, the complex phenomena occurring within a rocket combustion chamber, are still far from being fully understood. These systems, due to performance requirements, generally operate at high chamber pressures, exceeding the critical point of typically employed propellants such as cryogenic liquid oxygen (LOx), liquid hydrogen (LH2) or the newly proposed methane (LCH4). The fluid dynamic and reactive behavior of such supercritical fluids is still under investigation. Moreover, in transcritical injection conditions, i.e. when pressure is above and temperature below the critical value, the LOx undergoes a pseudo-transition of state, referred to as pseudo-boiling, as it is heated from the trans- to the supercritical state. Associated to pseudo-boiling is a strongly non-ideal, real gas behavior and an abrupt volumetric expansion leading to drastic changes in flame morphology, which could affect combustion efficiency if not taken into account in the design process. The transcritical condition is systematically encountered in LRE, as propellants are stored in cryogenic state.

In this context, the present research project proposes the developement of a numerical software for the investigation of high pressure turbulent flames in LRE-like conditions, by means of both RANS and LES techniques. Concurrently, the development of a Direct Numerical Simulation (DNS) infrastructure is also proposed in order to assemble a database of turbulent mixing and diffusive flame problems in super- and transcritical conditions, in order to gain fundamental physical insight and assess new mixing and combustion models for high fidelity RANS/LES simulations.