Visualization of flow through planar double divergent nozzles by computational method

Abstract

The double divergent nozzle is a type of altitude adaptive nozzle. The double divergent nozzle does not have any mechanical parts, leading to reduced nozzle weight and requires minimum modifications to the existing launch system. The planar double divergent nozzle is a type of double divergent nozzle, having a rectangular cross section. The present study involved the numerical analyses of a single divergent nozzle, and five double divergent nozzle geometries. The flow is simulated on five different double divergent sections having the same area ratio, but with different inflection angles/extension length. All geometries are studied with similar boundary conditions. Flow pattern, wall static pressure, side load, and specific impulse are studied for pressure ratios ranging from 1.5 to 8.5 with cold air as working fluid. The results obtained are compared with a single divergent nozzle having the same area ratio. It is inferred that the flow pattern, side load, and specific impulse of a double divergent nozzle have a strong dependence on the inflection angle.