Several papers have been published on liquid rocket engines. Below is a collection of some. Some links are from ResearchGate so you need an account there (free for academics/students).
With 3D files:
Portland State Aerospace Society (PSAS) - Liquid-Propellant Engine (LPE) Designs
Papers without 3D models:
USC Liquid Propulsion Lab (USCLPL) - Balerion ...
I'm not going to do this beautiful beast of a paper justice, so by all means, feel free to dig into it yourself. It actually looks pretty readable, although processing all the math and theory would take me about an hour per page. But luckily, the highlights are at the end:
For chugging (low frequency instability):
"4. The frequency of unstable ...
Fuel Stored Energy: 942.42 TJ/kg
This seems implausibly high. Are you sure of your numbers here? It seems at least 50% higher than optimistic approximations of D-3He fusion, which seem to assume a rather optimistic burnup fraction.
Working backwards from your thrust figures gives a more plausible energy density (eg. ~170TJ/kg assuming the whole pellet mass ...
"If the pressure in the combustion chamber has to be exceeded by the pressure provided by the pumps, is it also exceeded by the pressure in the gas generator. "
Just to be clear, there's no "if" about this ==> "the pressure in the combustion chamber has to be exceeded by the pressure provided by the pumps"
Addressing "is ...