Numerical Simulation And Experimental Research On Scramjet Combustor Based On Cavity-Strut Flameholder

was focused on in this paper. The flow field was observed by means of NPLS technology, with which the complex supersonic flow structures could be imaged at high spatiotemporal resolution, and the velocity field as well as the vortices distribution could be calculated by supersonic PIV system. The hybrid RANS/LES strategy was employed in numerical simulation of the scramjet combustor. The characters of the flow field about the strut and the combustor could be analyzed by means of experimental and simulant methods.The flow field around the strut was drawn a conclusion as follows. Arched shock was formed in front of both the horizontal strut and the vertical strut. The boundary layer on the side surfaces of the strut was thin. The recirculation zone was formed by the fallen boundary layers of the side surfaces at the rear of the strut where the flow coming from both sides turned around and struck against each other, as a result, the flow was forced to turn around again and Carmen vortex was developed downstream. A pair of vortex flow was generated from the head of the vertical strut, which was smaller on the short side of the horizontal strut.The characters of non-reaction flow field in scramjet combustor were resulted from the study as follows. Exchange of mass and momentum was promoted by the intersection of cavity and sidewall in the scramjet combustor. Vortex was broken up due to the intersection of the arched shock wave and the shear layer belonging to horizontal strut and cavity respectively. The flow was driven into the cavity under the power of high pressure behind the shock wave. The recirculation zone at the back wall of the cavity was beneficial to mixing enhancement and flame holding. As for the vertical strut, the recirculation zone at the rear was bigger and good for mixing and flame holding. The flow was slowed while the pressure was higher after passing through the oblique shock waves behind the vertical strut, so the shear layer over the cavity leaned to the bottom resulting in expansion waves at the front of the cavity and induced the high speed flow beside to enter into the cavity, which was good for flame holding obviously.The situation of the scramjet combustor was studied under the condition of high back pressure in this paper, and the conclusion was arrived as follows. Large vortex was often generated due to the recirculation zone at the rear of cavity, which was beneficial for mixing enhancement and flame spread, but the large vortex could also generate complex shock waves by extruding the supersonic flow, which broke the oblique shock wave at the front of the cavity and disturb the core flow. The vortex disturbing the core flow could be restrained by horizontal strut effectively while the enhancement of mixing was kept, but the large vortex was induced to the front of the cavity by both the shock wave at the front of the strut and the recirculation zone at the rear of the cavity, therefore, the boundary layer of the coming flow become thicker probably and the core flow might be influenced. The recirculation zone was filled with large vortex on condition of high back pressure, which could perform well in mixing enhancement and flame holding but also might choke in the working process of scramjet combustor.