Numerical Analysis of Aerospike Engine Nozzle Performance at Various Truncation Lengths

Abstract

The aerospike engine was first devised in the early 1960s where it provided new means of reaching orbit in a single stage. The paper aimes to demonstrate the viability of the technology by showcasing the increased nozzle thrust efficiency over the conventional bell nozzle. Various truncations were applied to the nozzle and each was subjected to two conditions, an over-expansion and near optimum condition. The nozzle contour was developed using the simple approximation method and was chosen to replicate that of the XRS-2200. This anchored the data, thereby validating the computational fluid dynamics (CFD) simulation. Simulations were completed for at nozzle pressure ratios (NPR) of 58 and 15. Velocity vector plots and contours were generated in which the recirculation region can be clearly identified. This region is a result of the negative thrust contribution of the base and grows increasingly negative when the truncation applied increases in addition to when the exhaust flow is over-expanded. The results demonstrate the performance gain of the full-length aerospike nozzle, , over all other truncations. At NPRs of 58 and 15 it showed 1.5% and 10.3% gain respectively in the nozzle thrust efficiency compared to . There are, many impracticalities related to the full-length aerospike including cooling on the nozzle. Therefore, provide a realistic nozzle truncation that would be implemented. Although radical design changes to the rocket will be required for the adaptation of the aerospike engines, the changes will be beneficial in the long term. By increasing the nozzle thrust efficiency compared to bell nozzles, less fuel will be required per launch. Furthermore, removing the multi-stage method currently used, overall, the rocket will have an increased reliability due to its reduced complexity.