气动塞式喷管底部压强模型研究

Studies on Base Pressure Model of Aerospike Nozzle

为了解塞式喷管底部压强特点,找出快速、准确计算底部压强的方法,实验研究了不同反压下塞式喷管的底部压强。在认识外界反压对塞式喷管流动作用机理的基础上分析如何确定不同的底部气动状态,将塞式喷管底部在不同外界反压下的气动状态划分为“三段”,即底部开放段、底部闭合段和底部由开到闭的过渡段,在各段,底部压强使用不同的计算方法。把数值模拟、实验研究及塞式喷管底部自身特点结合起来,找出塞式喷管底部压强的一般规律,建立了适合于工程应用的底部压强计算模型。结合40%和20%截短塞式喷管的实验数据,验证了底部模型的正确性。塞式喷管底部流动是超声速流的大分离流动,该模型对底部压强的预示比有限差分法具有更高的精度。

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 aeruspike nozzle base region is the large separation of supersonic flow and the base pressm＇e predicting results are more accurate by the model presented in the paper than the finite difference method.