Evaluation of the influence of surface roughness on the deterioration of heat transfer in methane rocket engine cooling systems

The need for advanced propulsion systems for space exploration has led to extensive research into the cooling mechanisms of rocket engines. This study investigates using methane as a coolant under transcritical temperature and supercritical pressure conditions, focusing on understanding heat transfer deterioration. The Reynolds-Averaged Navier–Stokes equations are solved numerically for pure methane flowing in a high aspect ratio cooling channel for different operating conditions. The GERG-2008 equation of state and extended corresponding states models are used to calculate the properties of methane. The Simulation results showed that the optimum height of wall roughness size is directly linked to the applied heat flux and mass flow rate for each specific operating pressure. The surface roughness of the cooling channels must be carefully designed and manufactured for each specific supercritical operating pressure to maximize heat transfer and minimize pressure drop. This research improves the cooling system designs for rocket engines, which could lead to more efficient and reliable propulsion systems for future space missions. • The impacts of sand grain roughness on HTD are discussed. • The effects of heat flux and mass flowrate on HTD are investigated. • HTD depends on critical pressure, critical temperature, and operating pressure. • Thermal performance factor is used to evaluate the sand grain roughness height.