A CFD Simulation of High Altitude Testing of the Cryogenic Engine

Abstract

A rocket designed to operate in outer space will show deviation in performance when tested at sea level. This is because of the large back pressure (1 bar) acting on it. Therefore it is tested by simulating high altitude conditions in controlled environment called High Altitude Testing (HAT). This is necessary not only for testing and developing the Engine but also to fully qualify it to be integrated into the launch vehicle. This report briefs about the design of a HAT facility. It presents a view on difficulties during CFD simulation and manual testing of the Engine. It provides a work-around for mesh interfacing of various parts. It shows how to select a suitable working fluid for the Ejector in order to create vacuum. It also shows the optimisation of mass flow rate of Nitrogen and Steam for the Ejector. It glimpses the Aero-Thermal behaviour of Nozzle flow with both Ejector On and Off conditions to prove self-pumping mode. It studies the Engine start up mode operation. It focusses on Engine shut down transient analysis. It also focusses on the re-entry of air into the facility during this process. It shows the role of Ejector in preventing re-entry of air and delaying flow separation in the Nozzle during this process.