Experimental and Numerical Investigation of Heat Transfer Processes in Rocket Engine Cooling Channels Operated with Cryogenic Hydrogen and Methane at Supercritical Conditions

Abstract

Hydrogen and Methane are two fluids that are either used or in discussion as propellants for upper and lower stage rocket engines. The conception of a regenerative cooling system is a crucial part in the design of a rocket engine and so is the detailed knowledge of the coolants behavior and the heat transfer capabilities. Hydrogen is a very efficient and well known cooling fluid whereas the properties of methane as a cooling fluid are intensively investigated nowadays. Experiments were performed with a subscale combustion chamber that is divided into four sectors around the circumference each containing rectangular cooling channels with different aspect ratios. Cryogenic hydrogen and liquid methane were used as cooling fluids. These experiments provide a broad data basis that is used for the validation of CFD simulations. The simulations are capable of predicting wall temperatures for high pressure conditions. Thermal stratification effects that are known to limit cooling properties in high aspect ratio cooling channels arise for both fluids, but the effects are much stronger for hydrogen compared to methane. However in the vicinity to the critical point, when it comes to heat transfer deterioration, the simulations show large deviations to the experimental values.