What temperature difference do the injectors in a cryo engine experience?

Question

A quick follow-up to Does ISRO's Cryogenic Upper Stage have restart capability?

What temperature difference do the injectors in a cryo engine experience between the propellant tank, and the ignition chamber?

Answer 1

If you refer to page 25* of this Space Shuttle Main Engine orientation you will see that the LOX enters the engine at -297 deg F (-183 C) and the LH2 enters at -423 deg F (-253 C), whilst the main combustion chamber runs at a toasty 6000 deg F (3316 C).

You ask specifically about the tank temperatures; if I recall correctly, there was a small temperature rise from the tank to the engine inlet (the lines were all vacuum-jacketed to minimize this), but this pales in regard to the enormous temperature rise across the engine.

This is the biggest total temperature rise; the figure also shows the temperatures at the preburner inlets and their combustion temperatures.

*(page 25 of the .pdf, the page number is 19)