Design method for wide-speed-range variable geometry inlet based on one-dimensional model

Abstract

The two-dimensional inlet, a critical component of scramjet engines, encounters substantial design challenges, particularly when operating over a wide-speed range. To accelerate the design process, a one-dimensional model-based methodology is proposed, encompassing three main stages: initial geometric design, boundary layer modification design and variable geometry design. Among these three stages, the boundary layer modification design ensures a flow coefficient of 1.0 while accounting for boundary layer effects under design point conditions. And the variable geometry design can enhance the startability of the inlet under off-design point conditions. Moreover, a newly proposed uniformisation model is applied at the inlet exit. The results indicate that the performance parameters calculated using the one-dimensional model are in good agreement with the numerical simulation results, although minor discrepancies exist for some parameters, thereby demonstrating the reliability of the design method. Additionally, the designed inlets exhibit superior performance and a lower self-starting Mach number. Overall, the one-dimensional model method enables the rapid design of two-dimensional inlets, offering a valuable tool for reducing the inlet design cycle.