Large-eddy simulation of a supercritical channel flow using a shock capturing numerical scheme

Abstract

This paper investigates the simulation of supercritical fluids flowing inside small cooling channels. In the context of liquid rocket engines, a strong heat flux coming from the combustion chamber (locally ϕ≈80MW/m2 for the Ariane 5 main-engine) may lead to very steep density gradients close to the wall. These gradients have to be thermodynamically and numerically captured to really understand the mechanism of heat transfer from the wall to the fluid. A shock-capturing WENO numerical scheme, usually used with the ideal gas law, was extended to real gases and applied to the simulation of an academic channel flow configuration that uses hydrogen as fluid. Results showed very elongated ligaments in the streamwise direction with a deep penetration in the wall-normal direction. A linear analysis was performed to link the fluctuations of compressibility factor (Z′) to temperature fluctuations (T′) in the case of an adiabatic and isothermal wall. The usual Strong Reynolds Analogy (SRA) could not be confirmed with real gas effects. Z fluctuations was found lower than 1%, thus becoming harder to distinguish the physical fluctuations from the numerical error and a more refine simulation should be require to deliver a definitive conclusion.