Transient Heat Transfer Modeling in an MFPL operating in Blowdown mode

• DOI: https://doi.org/10.22533/at.ed.317462423025

• Palavras-chave: Rocket Engine, Liquid Propellant, Propulsion, Blowdown, Heat Exchange.

• Keywords: Rocket Engine, Liquid Propellant, Propulsion, Blowdown, Heat Exchange.

• Abstract:

  Modeling the heat exchange, in liquid propellant rocket engines (MFPL), between the gases resulting from combustion and the chamber walls, is essential to determine the type of material used in the chamber as well as its thickness, especially when there is no system of refrigeration. For MFPL’s that operate in blowdown mode, this heat exchange is transient throughout engine operation, since there is no stationary mode of operation. The system used is based on an initial value problem of the engine's modus operandi, where the greatest pressure difference between the chamber and the propellant tanks is when the valves open, since the pressure in the chamber is ambient. To calculate the transient heat exchange, engine operating curves (pressure, thrust, mixture ratio, etc.) over time were first generated. With these, the convective and radiative heat exchanges between the gases and the chamber and the radiative heat exchange between the chamber and the external environment were calculated. The results showed that the greatest heat exchange is in the region close to the nozzle throat. Furthermore, for the engine analyzed, it was necessary to use a greater thickness in the nozzle region to avoid causing structural failure of the material.