Investigation of the influence of single expansion ramp nozzle geometric parameters on the flow field and performance

Based on CFD technology, the effects of major geometric parameters on performance of the single expansion ramp nozzle were numerically investigated by solving Reynolds average Navier-Stokes equations and standard two-equation k-ε turbulent models. The results show that upper ramp length, upper ramp angle, lower flap length, lower flap angle have evident effects on flow field structure and the performance of SERN. With the increase of upper ramp length, the expansion in SERN transits from under-expansion to over-expansion, thus an optimal upper ramp length is found to create maximal thrust coefficient. The upper ramp angle, lower flap length, and lower flap angle also have optimal values for SERN performance.