结构参数对两相冲压发动机喷管性能影响分析

Effect of structure parameter on nozzle performance of bubbly water ramjet engine

关键词:  冲压喷气发动机  喷管效率  结构参数  数值仿真

Key words:  Ramjet engine  Nozzle efficiency  Structure parameter  Numerical simulation

摘要:

为了分析气液两相冲压发动机的喷管参数对推力及效率的影响,分别针对不同参数条件下喷管中泡状气液两相流场,基于双流体模型,采用变步长的Runge-Kutta法进行数值模拟。并对喷管中临界泡状流进行分析,重点研究了喷管喉部与入口面积比、半扩张角和半收缩角在各种气液质量流率比条件下对喷管推力及推进效率的影响,计算结果表明,推力随着喷管喉部与入口面积比增大而减小,气液质量流率比较大时,效率随其增大而增大;半扩张角增大时,推力和效率同时减小;半收缩角对喷管推力及效率影响均不大。在给定的喷管参数下,气液质量流率比在一定程度上增大时,喷管推力及效率同时增大。

Abstract:

To obtain the influence of the nozzle structure parameter to the thrust and efficiency for bubbly water ramjet engine,critical bubbly flow through converging-diverging nozzle was studied numerically with two-fluid model and variable step Runge-Kutta scheme.The results agree well with the experiment.The impact of area ratios(throat to inlet area At/A0),half diverging angle(β)and half converging angle(α)to the thrust and efficiency were investigated by comparing the simulation results.Different mass flow rate ratio(μ)was considered.With increasing the area ratio At/A0,the thrust decreases rapidly but the efficiency increases.The increase in half diverging angle β reduces the thrust and efficiency.The impact of α to the thrust and efficiency is minor.In a certain nozzle,greater thrust and efficiency can be achieved by increasing μ.