Effect of Exhaust Nozzle Diameter on Internal Flow Field Characteristics in Base Bleed Unit Simulator

Abstract

For the optimal design of base bleed unit, a 2D-axisymmetric unsteady model was established and the effects of different exhaust nozzle diameters on the internal flow field were studied. Results show that the larger the exhaust nozzle is, the higher the depressurization rate and the mass flux are at the earlier stage of depressurization, and the lower the pressure, the temperature, the density in the base bleed unit and the flow rate at the nozzle outlet are. But at the later stage, the depressurization rate and the mass flux are smaller instead. The radial temperature is generally unchanged in most part far from the burning surface and increases near the burning surface at the earlier stage of depressurization, whereas it is lowest at the axis and rises up quickly along the radial direction at the later stage. The radial density distributes just oppositely.