Studies on base pressure model of aerospike nozzle

To investigate the feature of aerospike nozzle base pressure and find a method to compute base pressure quickly and accurately, aerospike nozzle base pressure at different ambient pressure were experimentally studied. Based on the analysis of effect of ambient pressure on aerospike nozzle flowfield, methodology predicting base behaviour was presented. In the paper, base behaviour of the aerospike nozzle at different ambient pressure was divided into three parts namely open base, closed base and open-to-close transition and different base pressure calculating formulas were employed in different parts. On the basis of numerical simulation, experiments and aerospike nozzle base characteristics, a base pressure prediction model for engineering was presented. The base pressure prediction model was validated by experiments of 40% and 20% truncated aerospike nozzle. Wake flow at aerospike nozzle base region is the large separation of supersonic flow and the base pressure predicting results are more accurate by the model presented in the paper than the finite difference method.