Enhancement of scramjet inlet efficiency by geometrical modifications

Abstract Scramjets are considered one of the important propulsion systems for realizing hypersonic flights and have attracted a lot of research interest over the past few decades. The present study focuses on conducting a comprehensive numerical investigation on a scramjet inlet-isolator at Mach 5 with the motivation to improve efficiency. The study investigates a two-dimensional scramjet inlet-isolator, analyzing both external and internal flow characteristics by using the commercially available tool Ansys-Fluent. Numerical simulation is the first step to incorporate the passive bleed mechanism into the inlet design features with alterations aimed at improving airflow regulation. The subsequent investigation is the analysis of the effect of a number of cowl deflection angles on performance of the positions. An extensive evaluation is presented on the effect of varying cowl deflection angles on the inlet isolator efficiency. A combined approach is also adopted in the study whereby the most promising configurations from the bleed mechanism and cowl deflection angle studies are incorporated into a single geometry. This aims at increasing the inlet isolator efficiency and the pressure recovery. The aim of this integrated strategy is to develop an inlet geometry that is optimal for performance of the engine and pressure recovery capability enhancement. The study analyzes ten different cases, and it is noted that out of these, the 4-degree cowl deflection angle is the most efficient in enhancing the total pressure efficiency.