COMPARISON OF PSEUDO-SHOCK FLOWS IN DIVERGENT DIFFUSERS OF AXISYMMETRIC AND TWO-DIMENSIONAL INLETS OF INTERNAL COMPRESSION
Results of a comparative numerical study of flows in axisymmetric and two-dimensional inlets flown by the supersonic free stream with Mach numbers M = 6 are presented. The flow conditions corresponded to forming a pseudo-shock wave downstream of the throat in the divergent diffuser of each inlet. It was assumed both the inlets provide nearly equal mass-averaged Mach numbers of the flows at the initial cross sections of the diffusers. A Reynolds-averaged Navier-Stokes code and the k-ω SST turbulence model were applied to compute the flows. The problems were solved by the pseudo-unsteady method. The flows of an ideal gas (air) with the stagnation temperature constant everywhere were considered. The inlet walls were assumed to be adiabatic. The flow patterns in the inlet ducts were obtained as well as overall characteristics of the pseudo-shock wave were determined depending on a backpressure value at the diffuser exit. The backpressure was changed by throttling the inlet duct with the use of an exit narrowing nozzle. Characteristics of varying the flow turbulization in the pseudo-shock region were computed. Specifically, the axial distribution of the turbulent viscosity was determined, which allowed to determine the total length of the pseudo-shock wave corresponding to the maximum of this distribution. The losses in the total pressure recovery were estimated as for the pseudo-shock wave, properly, and for the inlets, in general. It was determined the effect of the backpressure level on the pseudo-shock wave position in the diffusers and on a moment of its shifting upstream into the inlet throat with subsequent breaking the inflow at the inlet entrance.