Prediction of liquid oxygen flow rate and experimental verification during throttling

Abstract

Considering the heat input and the resulting density change, the mass flow rate of liquid oxygen was predicted and compared to the results of cold flow tests. The prediction error of the flow rate was within 2 % assuming a constant heat transfer coefficient. Temperature rise between the tank and the injector manifold located at the exit of the piping system was also well explained by the suggested model. The discharge coefficient of the injector was found to be constant (Cd=0.66) at a mass flow rate larger than 120 g/s but became smaller at a lower mass flow rate. At a deep throttle condition (less than 10 % of the full throttle), vaporization of oxygen occurs at the injector manifold and the predicted mass flow rate was significantly deviated from the experimental result.