Rocket nozzle cooling

During the combustion of a rocket engine, the temperature of the flow inside the nozzle exceeds the maximum service temperature of the wall materials. A cooling system is required to transport the heat away in order to cool the walls of the rocket engine.

The liquid hydrogen that is used for the combustion is also used for cooling the rocket nozzle. Multiple small channels along the wall are used to cool down the walls. The massflow inside these channels are limited to the amount hydrogen used in the combustion chamber. Using the hydrogen to cool the nozzle means that less heat is lost and the efficiency is increased.