固体火箭高温高压复杂燃气系统的扩散系数及其相似准则数计算

为了解决固体火箭推进剂高温高压燃气输运系数难以实验测量和理论预估的实际问题,考虑燃气中含有H₂O、HCl、SO₂等强极性组分和H₂等轻质组分,通过大量文献实例验证,归纳了适于上述组分及其混合物在高温高压条件下的扩散系数计算方法,并计算了典型双基推进剂、复合改性双基推进剂和复合推进剂三种主要固体推进剂燃气在不同温度(1 500～3 800 K)和压强(8～20 MPa)下的扩散系数和输运准则数(施密特数和路易斯数),得到了固体火箭发动机燃气扩散系数随温度和压强变化的幂指数函数规律(典型双基推进剂燃气的扩散系数随温度变化的幂指数为1.646 55、典型复合改性双基推进剂和典型复合推进剂为1.629 52),以及路易斯数、施密特数的典型取值(典型双基推进剂燃气的施密特数为0.772、路易斯数为0.91,典型复合改性双基推进剂燃气的施密特数为0.675、路易斯数为0.9,典型复合推进剂燃气的施密特数为0.74、路易斯数为0.83)。这对于促进高温高压气体混合物输运性质的深入研究、火箭发动机燃烧及其内外流动仿真,均具有重要的实际应用意义。该方法没有考虑凝聚相对输运性质的影响。

Calculation of Diffusion Coefficient and Transport Similarity CriterionNumber of High-temperature High-pressure Gas Mixture of Solid Rocket

The transport properties of high-temperature high-pressure combustion gas in solid rocket motor are difficult to be estimated and experimentally verificated. To solve the problem,it was considered that the rocket gas contained strong polar components such as H₂O,HCl,SO₂ and light components such as H₂. The calculation methods of diffusion coefficient of these components and their mixtures under high temperature and high pressure were summarized by a large number of literature examples. The diffusion coefficient and transport similarity criterion numbers such as Schmidt Number and Lewis Number of three main solid propellant gases of typical double base propellant,composite modified double base propellant and composite propellant were calculated at different temperatures(1 500～3 800 K)and pressures(8～20 MPa). The power exponential function law of diffusion coefficient changed with temperature(The power exponent of the diffusion coefficient of typical double base propellant gas changing with temperature is 1.646 55,and that of typical composite modified double base propellant and typical composite propellant is 1.629 52)and the typical values of Schmidt Numbers and Lewis Numbers(The Schmidt Number and Lewis Number of typical double base propellant gas are 0.772 and 0.91,and those of typical composite modified double base propellant gas are 0.675 and 0.9,those of typical composite propellant gas are 0.74 and 0.83)of solid rocket motor gases were obtained. The obtained results have important practical significance for the in-depth study of promoting the transport properties of high-temperature high-pressure gas mixtures,combustion mechanism on rocket engine and simulation of its internal and external flow. The influence of condensed phase on transport properties is not considered.