Experimental and numerical study of flow structure and liner wall temperature in reverse flow combustor

Mini turbojet engines are becoming attractive in the study of unmanned aerial vehicles since it provides rather high thrust to weight ratio. Consequently, the distance, flight time, and payload performance can greatly be improved. The experimental and numerical studies can supply the guidance for the future design. The engine consisting a centrifugal compressor, an axial turbine, and a reverse flow combustor has been studied experimentally, the temperature the pressure at the combustor and the emission are measured in the test rig under the various working conditions. The numerical models are employed and validated against the experimental data under different working conditions. The standard k-ϵ model with standard wall function and the -function Probability Density Function model are applied. The combustion modeling coupled with discrete phase model is built up to analyze the specific flow filed inside combustion chamber, in the light of temperature and pressure distribution, the liner wall temperature. The simulation results are compared with the experiments for a kerosene fuelled combustion chamber. In addition, post-processing model for predicting NOx emission is presented. Although liner wall temperature is not captured in the experiments, numerical prediction for hot spot is involved in the study, which leads to main damage to the liner and shortens the combustor life span.