Since graphite in solid rocket nozzles need NO COOLING, they are VERY SIMPLE. But hot graphite burns with air and oxidiser, so liquid engines don't use it (so I gather). How do people with knowledge on rocket engines think of the following chamber wall designs:
-Graphite wall lined with magnesium oxide
-Graphite wall for upper stage engine with combustion chamber wall protected by Vortex Flow Field of fuel.
-Graphite wall lined with magnesium oxide
-Graphite wall for upper stage engine with combustion chamber wall protected by Vortex Flow Field of fuel.