固体火箭发动机零维两相燃烧室压强计算方法研究

Research of Two Phase 0-D Chamber Pressure PredictionMethod for Solid Rocket Motor

关键词:  固体火箭发动机  燃烧室压强  计算方法  两相流

Key words:  Solid rocket motor  Chamber pressure  Prediction method  Two phase flow

摘要:

为了更准确地预估含金属燃料固体火箭发动机的燃烧室压强，在压强计算中考虑两相流的影响，从一维两相喷管流动的求解出发，通过两相平衡流模型、两相常滞后模型、两相等温流模型、颗粒定温模型等模型的简化，分别推导不同模型下喷管中两相混合物的流量计算公式，再把流量公式应用到发动机零维内弹道理论中，推导并简化得到零维燃烧室平衡压强的计算公式。把压强公式用于HTPB推进剂固体火箭发动机和铝冰固体火箭发动机的燃烧室压强计算，结果表明，当固体推进剂中金属含量较高时(如铝含量为21%的HTPB推进剂发动机)，用传统零维燃烧室压强公式预估的压强与实验误差较大，而使用合适的两相流模型和对应的零维燃烧室压强计算方法，在HTPB发动机中，能把压强预估结果与实验的误差降低到6%以内。如果使用多维内流场计算的方法，燃烧室压强预测结果的误差将下降到2.5%以内。结论发现在含金属固体火箭发动机的燃烧室压强计算中，考虑两相流的影响是必要的，而使用两相流修正后的零维燃烧室压强计算公式能够快速、较准确地预估这些发动机的燃烧室压强。

Abstract:

In order to predict the chamber pressure of the metallized Solid Rocket Motors(SRMs) more accurately， the effect of two-phase nozzle flow was considered in the pressure calculation. The research begins from the solution of one-dimensional two-phase nozzle flow， and by the method of theoretical derivation and simplification， several theoretical models were proposed to solve the controlling equations. These models include two phase equilibrium flow model， two phase constant lag model， two phase isothermal model， and constant particle temperature model. Under each model， the total mass flow rate formulas of the gas-particle mixture in the nozzle were derived， as well as the zero-dimensional(0-D) chamber pressure formulas at the steady working state of the SRM. All the pressure formulas were used to calculate the chamber pressure of a metallized HTPB SRM and an aluminum-ice SRM， the results showed that when the propellant’s metal content is high(like the HTPB SRM with 21% aluminum in the propellant)， the traditional 0-D chamber pressure formula will lead to big errors， but by choosing a suitable two phase flow model and its corresponding chamber pressure calculation method， the errors can be reduced to less than 6% in the HTPB SRM. When the multi-dimensionnal(normally 2-D) numerical calculation method were used， the errors can be reduced to less than 2.5% in the HTPB SRM. It is concluded that in the calculation of chamber pressure in metallized SRMs， the two-phase-flow effect needs to be considered， and by the use of two phase corrected 0-D pressure prediction method， quicker and more accurate prediction results can be reached.