Assuming a simple rocket engine, with a combustion chamber and de laval nozzle, fueled by liquid methane and liquid oxygen, what temperature must the combustion chamber, choke and nozzle withstand?
From a university article, the adiabatic temperature of a perfect mix would be about 5000C:
However, when combustion products expand they cool, so this question could be rephrased as what pressures exist in the three main parts of the engine.
Really I am asking "how tough does the inside of a rocket engine need to be"? What is the max temperature and pressure the materials must be able to withstand?