Effect of transonic inlet design on the performance of a micro-turbojet

摘要

Unmanned air vehicle should cover trajectories with large variations of speed and angle of attach. In order to expand the current operating ranges of UAVs, dedicated propulsive systems must be designed. Alternative solutions like compact turbojets and turbofans have been proposed. Especially in the transonic range, the performance of the intake has a large effect on the operation of the entire engine. In this paper, a methodology for designing optimal inlet geometries for transonic operation using computational fluid dynamics is proposed. Selected designs are assessed at off-design conditions to quantify the effect of flight Mach number and angle of attack. The performance of the intake is summarized into a map of recovery pressure in function of the operating conditions. The map is integrated into an engine model built using T-MATS, in order to assess the changes in engine consumption at different regimes of the inlet. The paper outlines a procedure for designing high speed engine intakes and characterizes the effects of angle incidence on a chosen optimized geometry in terms of pressure recovery and engine performance.