Evaporation of Injected Oxidizer from a Pressure –Swirl Injector in a Low Pressure Combustion Chamber

In this study, the evaporation of liquid oxidizer inside a combustion chamber during engine start-up in a low-pressure environment is numerically investigated. In thruster starting stage, first, a portion of oxidizer which has been evaporated inside the injector capillaries fills the void inside the combustion chamber and causes a pressure rise (up to 0.2 bars). This makes the injection of oxidizer as fluid possible and now the evaporation rate can be investigated. In the investigated thruster the mass flow of injected liquid is 3 grams per second and the type of injector is pressure-swirl. Numerical simulation in this study is based on an Eulerian- Lagrangian method known as Discrete Phase Method (DPM), which investigates the interaction of two phases using Navier-Stokes Equations. A verification is done to support the results of the method used in order to obtain quantitative variables essential to this study. The tendency of fluids to reach a stable state after an abrupt process of flashing is visible in the results of this study. After a small period of time around 20 milliseconds a stable temperature around 264 kelvins is reached which causes a stable pressure of 7 kPa in the combustion chamber.