Research On The Flow Characteristics Of The Dump Diffuser

In a modern aircraft engine system, combustor diffusers play a crucial role in minimizing total pressure loss as well as providing and maintaining a stable flow pattern for efficient combustion and an acceptable temperature profiles for turbine nozzles. In addition, diffusers are becoming increasingly vital as combustion standard improves gradually and there has been a marked rise in compressor discharges velocities. A great number of studies have been long since conducted on dump diffusers. Nevertheless, they are still expected to improve for the old computational fluid dynamics and experimental measurements used at that age. This paper focuses on the flow phenomena and pressure field in a dump diffuser system with the help of more modern and advanced CFD and digital pressure collection technique. And it should be noted that there is one angle of 24 o in this paper which is consistent with the typical configuration of a real combustor system.Certainly, this will make influence on the flow pattern. All of these efforts make sure that this paper is a combination of theoretical and practical thing which may throw new and practical light on the combustor design.This paper designs a typical combustor case model first and then focuses on the potential key structure and aerodynamic parameters by changing the parts of the model or inlet flow condition.Specifically speaking, this paper focuses the influence of divergence angle,dump gap,pre-diffuser protrusion length,dump angle,Mach number and velocity distribution. The CFD results show the flow and pressure regular pattern providing sufficient support for the experiment design.The CFD simulation and experimental results clearly show that divergence angle,dump gap,pre-diffuser protrusion length, Mach number and velocity distribution have a great effect on the pressure-recovery coefficient and loss coefficient of the dump diffuser but the dump angle not.