Aerodynamic design optimization of a bellmouth shaped air intake for jet engine testing purposes and its experiment based validation

Abstract

Jet engine ground tests are carried out with bellmouth shaped air intakes in order to measure the mass flow rate and the inlet flow quantities while supplying the engine an undisturbed flow. Although there are a variety of design standards and academic guidelines for the design of bellmouths, they can be designed to reach a lower total pressure loss coefficient, a less disturbed radial velocity profiles for the engine and a less thickened boundary layer at the engine inlet. This enhanced design can be achieved with the help of optimization algorithms and computational fluid dynamics (CFD) computations thanks to the increasing average computational power and simplicity of the flow problem. In this study, a genetic algorithm based optimization method and a RANS solver under a commercial software platform are applied to find a bellmouth design with less loss and less disturbed flow. An elliptical bellmouth lip profile with a linear extension part is defined with parametrization and a wide range of parameter space is investigated during the design work. Optimum design candidates are presented comparatively regarding the design purpose. The selected design candidate is produced and tested for CFD validation.