Numerical analysis of curved thrusters for multichamber aerospike engines in flight conditions

摘要

The paper investigates thruster nozzle shapes for use in annular multichamber aerospike engine configurations. A thruster shape with a supersonic nozzle section curved in the circumferential and longitudinal directions is presented and compared to a classical linear thruster configuration. The multithruster aerospike engine flowfield along a typical ascent trajectory including slipstream effects is investigated by solving the Reynolds-Averaged Navier-Stokes with a realizable k - ϵ turbulence model. Longitudinal curvature leads to a radial pressure stratification of the thruster exit flow (caused by internal expansion and compression waves), with a decrease in pressure at the plug nozzle and an increase at the outer thruster lip. Circumferential curvature leads to a more homogeneous flow in the lateral direction, reducing pressure peaks at thruster intersections. For a fixed overall engine diameter, the larger engine nozzle area achieved with dual curved thrusters leads to performance improvements of about 2% when compared with the linear design. Improvements result from increased thruster performance at higher pressure ratios and a larger contribution of the plug, which has a larger area. In addition, engines with curved thrusters use a greater portion of the launcher's cross section and thus reduce base drag.