The rocket is a non air breathing engine. It carries the fuel and the oxidizer. The exhaust provides the momentum for forward flight
Fluid Mechanics Model
Simple Momentum Equation
Titan Rocket
High Isp requires high R (low molecular weight), high T0.
T0 (also flame temperature) is dictated by chemical combination of fuel/oxidizer mixture
Throat Relations
The design of the throat is critical for rocket engines. They sustain a particular mass flow rate at certain exit conditions.
The combustion chamber is idealized to have a stagnation conditions, and therefore the relations between the combustion and throat can be established by the compressible flow relations