Design and Unsteady Numerical Simulation of Variable Geometry Inlet Using Dynamic Meshes

Abstract

The fixed geometric inlet only has better performance near the design Mach number, and it is difficult to meet the demand of the combined cycle engine. A multistage adjustable variable geometry inlet with rotating cowl and ramp is proposed. The numerical simulation of variable geometry inlet with rotating cowl and ramp is performed by solving Reynolds Averaged Navier-Stokes (RANS) equations with dynamic mesh technique. The cowl and ramp rotating angular velocity have been modified using a parametric user defined function (UDF) that covers the whole range of operating points. Two methods (Spring-based Smoothing and Local Re-meshing) have been used to achieve the mesh deformation and re-meshing. The general performance of rotating cowl and ramp are investigated, respectively. The variable geometry scheme for the hypersonic inlet under different flow conditions has been studied by two-dimensional numerical simulation. Results indicate that both the cowl and the ramp rotating with constant angular velocity can help to enhance the self-starting ability. The variable geometry inlet with rotating cowl and ramp has better performance in the entire operating range. Especially, it can effectively reduce the inlet start Mach number and the inlet can self-start at Ma2. The variable geometry inlet has better flow capture ability. The mass flow rate coefficient comes to 0.53 at Ma2. The multistage adjustable variable geometry inlet scheme effectively solves the contradiction between the start and flow capture capability at low Mach number. Moreover, the variable geometry scheme for hypersonic inlet is simple and feasible in engineering application.