Differential model of the LPRE chamber cooling channel

Abstract

In a liquid rocket engine, the cooling channels of the chamber significantly impacts various system parameters. It limits the permissible mass ratio of fuel components, affects the required pump power, and largely determines the layout and weight of not just the chamber, but the entire engine. Consequently, due to the numerous interrelated parameters, making rational design decisions is impossible without reliable data on the thermal state of the engine chamber under different operating conditions. Additionally, heat transfer calculations are essential for analyzing fire test results and addressing defects identified during the development of the engine chamber. Given that regenerative cooling is the primary and most common method for cooling the engine chamber, this work focuses on it. Although research on flow-through cooling of liquid-propellant rocket engine chambers began in the 1950s, the issue of selecting optimal parameters for the cooling channels remains relevant. This is largely due to the numerous interdependent parameters in cooling systems. Key geometric parameters of the cooling channel include the height and width of the channel, the thickness of the wall and fins, the wall material, and the thickness of the protective coating. Additionally, factors such as changes in the properties of the coolant with varying pressure and temperature, surface roughness, which can differ for different walls of the same channel, and coolant characteristics like detonation, coking, or dissociation must be considered. This paper presents the results of calculations using a new differential model for the cooling channels of the liquid-propellant rocket engine chamber. The results validate all assumptions made during the model's development. The differential model is expected to enable heat transfer calculations with less effort, greater accuracy, and a more accurate representation of the various physical processes occurring in the cooling channels.