A Technology for Improving Regenerative Cooling in Advanced Cryogenic Rocket Engines for Space Transportation

Regenerative cooling of thrust chamber is the unique solution for the thermal management of high heat flux generated inside the combustion chamber of Cryogenic rocket engine. Heat is transferred from combustion hot gas to coolant through the channels provided on inner copper shell, thereby cools the inner wall of the nozzle. A novel technique of providing copper foam inside the channels will act as an infinite fin and also act as barrier for coolant stratification. This will improve the heat transfer to the coolant and reduce the nozzle wall temperature. Heat transfer improvement with copper foam inserts to the coolant channel is demonstrated through experiments with simulated fluids. Experiments are conducted with simulated hot gas chamber and coolant channels using water as the coolant. Copper foam with high porosity is selected to fill the channels. Hot tests are carried out with copper foam filled coolant channels and measured the coolant temperature rise and pressure drop across the channels. Tests are repeated with similar hot gas condition, but without inserting copper foam inside the channels. A substantial enhancement in heat transfer to the coolant is observed with copper foam inserts experiments, which will reduce the wall temperature. This gives a good handle on the life cycle improvement of multi-start cryogenic engines for future space transportation systems. This paper details the specification of copper foam, hardware design, experiments and measurements, and the application of the augmentation of heat transfer coefficient in operating cryogenic engines.