Sensitivity study of geometry parameters of the combustor dump diffuser

Experimental and numerical simulation studies were carried out to investigate the effects of different structural parameters on the performance and flow characteristics of the combustion chamber dump diffuser. The results show that different single structural parameters have different influences on the performance and flow field. When the expansion angle of the pre-diffuser is increased from 1.2° to 18°, the total pressure loss coefficient of the diffuser is reduced by 35.71%, 34.97% and 37.26% in the three working conditions, respectively. When the inclined angle of the pre-diffuser is increased from 0° to 30°, the total pressure loss coefficient of the diffuser increases by 48.57%, 50.79% and 49.43% in the three working conditions, respectively. When the relative dump gap ratio changes from 1 to 3, the total pressure loss of the diffuser first decreases and then increases. The expansion angle of the pre-diffuser has a major influence on the performance of the dump diffuser under different operating conditions, and the coupling between the expansion angle of the pre-diffuser and the inclined angle of the pre-diffuser has a major influence on the diffuser.