An investigation on bleed flow control of an axisymmetric supersonic intake based on parametric outline optimization design

Abstract

The intake plays an important role in the supersonic propulsion system, which restricts the performance of the entire propulsion system. It has been a challenge to ensure that the intake performs well in wide operating range. In this study, based on the multi-objective genetic algorithm, the baseline geometry of the intake is firstly optimized with Ma4 as the design point, and the total pressure coefficient at the outlet of the intake is 0.574. Secondly, in response to the performance decline and starting issues of the intake at off-design points, research is conducted on the scheme and physical mechanisms involving bleed flow control and the axial relative movement of the center body. The axial relative displacement of the center body decreases by 8.98 % due to the introduction of bleed slots, enabling the intake to start under conditions of larger internal contraction ratio. The mass flow rate loss caused by the bleed slots can be compensated by moving the center body and increasing the internal contraction ratio, as it enlarges the capture area of the intake. At Ma₀=4, the intake achieves a 2.58% increase in total pressure recovery with a 1.284 % bleed flow rate for the separation bubble eliminated. At Ma₀=1.5, the intake achieves a 6.47 % increase in total pressure recovery with a 6.6 % bleed flow rate, because the internal contraction ratio of the intake is enlarged and the terminal shock wave/boundary layer interaction is suppressed. But excessive bleed flow rate leads to the enhancement of terminal shock wave train which is detrimental.