Design methodology for shape transition inlets based on constant contraction of discrete streamtubes

Abstract

In this paper we propose a design concept, i.e. constant contraction of discrete streamtubes, to develop a new design method for hypersonic inlets with shape transition, which enables the shape transition inlet to have high compression efficiency while keeping flow uniformity as much as possible. The method first divides the 3D flow field of the inlet into several groups of discrete streamtubes with constant contraction ratio. The axisymmetric flow within each stream tube is then optimized via computational fluid dynamics to have high compression efficiency, and these discrete streamtube groups are finally assembled together by matching their shock wave reflection positions to form a 3D inlet flow field with weak crossflow. This method can be used for the design of shape transition inlets with specified entrance/exit sections. To validate the present methodology, we design a rectangular-to-circular inlet with a design point of Ma 6 and a takeover point of Ma 4, and examine numerically the flow structure and the inlet performances.