Design And Optimization Of Aeroengine Diffuser

The diffuser is one important component in the front of aeroengine combustion chamber,Its primary function is to slow down the air flow delivered by the compressor in order to increase static pressure recovery,promote efficient combustion and avoid large total pressure losses.With the increase of the pressure ratio of the aeroengine and the improvement of the combustion chamber performance,new performance requirements of the diffuser was put forward,it is necessary to reduce the total pressure loss while reducing the total pressure loss.In this paper,a single-channel diffuser and three-channel diffuser experiment scheme are designed according to the internal flow characteristics of the diffuser.According to the requirements of the experimental,the test pieces are designed and the experimental platform is built.Through the numerical simulation of single-channel diffuser and three-channel diffuser,The impacts of geometrical parameters such as the pre-diffuser wall angle,the dump gap ratio,and the aerodynamic parameters such as the inlet Mach number,the turbulence and the flow distribution ratio on the performance of the diffuser have been discussed.The formula of the total pressure loss Coefficient and the pressure recovery coefficient is developed in this paper.The results show that there is an optimal dump gap ratio and flow distribution ratio of the diffuser,most of the pressure rise occurs in the pre-diffuser,and most of the total pressure loss occurs in the dump.The expansion of the pre-diffuser wall angle can result in more static pressure recovery in the pre-diffuser,But the overlarge pre-diffuser wall angle will lead to the separation of the fluid in the pre-diffuser,and increase the total pressure loss.The guide vanes have an important effect on the performance of the diffuser,compared with the single-channel diffuser,three-channel diffuser can achieve greater pre-diffuser wall angle,and allows certain separation occur on the pre-diffuser,But the overall performance of the three-channel diffuser is not better than the single-channel diffuser.With the increase of the Mach number of the inlet airflow,the static pressure recovery of the diffuser increases,but the total pressure loss increases at the same time.Increased turbulence can inhibit fluid separation,when the inlet airflow turbulence is large,a larger pre-diffuser wall angle is more appropriated.