25

Really, there is nothing particularly special about it. Any liquid flowing through pipes in the engine wall will carry heat away from the engine as it heats up. Obviously, some liquids will be more effective than others. (Also, some propellants won't work because they'll either clog the pipes or explode, but RP-1 is especially formulated to avoid this). With ...


10

The volumetric heat capacity of liquids is much higher than that of gases. You need much more energy to heat a certain volume of water than the same volume of air. The density of liquids is much bigger than that of gases, that is why they can transport much more heat energy. Therefore a liquid flowing through a pipe takes away much more heat than a gas ...


5

Because it's 'free' energy for the taking! In a rocket, you have liquid fuels that need to be vaporized to burn correctly. To vaporize a liquid, you need to add heat energy to it: specifically its latent heat/enthalpy of vaporization, which is quite considerable. The enthalpy causes zero practical temperature increase: the substance is still the same ...


3

Just two short comments on the other excellent answers: Wall cooling is not free: What happens is that you (can) have a significant reduction in chamber pressure (depending on chamber size), reducing your thrust and efficiency. There may also be some second order effects on combustion efficiency when heat is removed from the process. So if we could run an ...


2

One certainly doesn't want a converging nozzle because the flow is already supersonic.  None have made use of converging or converging-diverging nozzles, because the exhaust is typically flowing at supersonic velocities and thus could be choked through the converging cross-section. This would result in a loss of energy that would decrease the overall ...


2

The speed at which heat is transferred from a surface depends on the transfer capacity of whatever is touching its surface and the speed at which it is taking that heat away from the surface thus making a heat gradient that pulls more heat out of the surface faster.(that's as simple as I could put it without fancy technical words) Rocket fuels that are ...


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