Numerical Investigation of the HIFiRE 2 Combustion Chamber

The study focuses on high-fidelity numerical simulations of several operating modes of the HIFiRE 2 Direct Connect Rig (HDCR) facility experiment. Wall Modeled Large Eddy Simulations of supersonic combustion have been performed in order to analyze the main flow features and compare wall pressure distributions with the experimental data. The combustion model is based upon finite-rate chemistry, with the Arrhenius-based closure provided by an ethylene-air skeletal reaction mechanism. A monotonicity-preserving flux reconstruction scheme based on central differencing and flux limiters was implemented in the solver, which has been written using the open-source CFD toolbox OpenFOAM. The governing equations were discretized and solved on a hexahedral structured grid, using explicit time integration and parallel computing. The modeling strategy has been carefully validated in many other studies. Results from the simulations are compared with the experimental results, showing poor agreement. Insufficient burning, delayed combustion, and different flow features have been observed. This fact is supposed to be related to the very large experimental uncertainties about key features of the experimental setup, such as the wind tunnel supersonic nozzle geometry, the target mass flow rate, and air composition of the Arc Heated Scramjet Test Facility. However, the flowfield data have been qualitatively analyzed in order to elucidate the complexity of the physical phenomena involved.