Numerical simulation method of surge experiments on gas turbine engines

In order to obtain the surge margin of an aero-engine during its operation, an engine surge experiment is required. A multi-dimensional simulation method for an aero-engine is established in this paper. The simulation of a surge experiment using high-pressure air-injection is then carried out on a turbo-shaft engine to obtain the surge boundary using this method. More specifically, firstly, a body-force model is employed to calculate the compressor performance owing to its capability of capturing the main three-dimensional features of compressor surge and avoiding excessive simulation time required by the traditional fully-three-dimensional Reynolds Averaged Navier-Stokes (RANS) method. Then, a one-dimensional model combining a lumped-parameter plenum model is used for the combustor to account for the propagation of pressure waves and the heat-release process, and a zero-dimensional throttle model is used to mimic the choking effect at the turbine nozzle. Finally, the air-injection system is modeled by imposing an injection boundary condition, which can be used conveniently in changing injection parameters. Based on the established method, the influences of different test parameters, such as the air-injection location, the pressure, the orifice size, the number of injection orifices, and the injection time duration on the surge characteristics and boundary are further studied, which offer effective guidance to optimize an actual experimental design.