Question

Rocket engines are cooled by fuel and oxidizer (e.g. liquid oxygen) circulating in pipes along their hot parts, before being burned. What do you think needs the cooling most--the combustion chamber or the wide "bell" through which the gases exit?

Answer 1

I'd say the combustion chamber probably needs it more but both require some form of cooling.

Answer 2

i'd say its bell cause ignition is in combustion chamber but most intense temperature would be in bell, my opinion...

Answer 3

After a bit of reading on the NASA site...I think you're right.