喷射器扩压室结构设计优化研究

Study on Structural Design Optimization of Ejector Expansion Chamber

扩压室对喷射器内混合流体的降速增压有着重要影响。本文基于真实流体物性,采用气体动力学方法建立改进的一维混合模型并提出扩压室结构设计优化方法。将模型计算结果与文献实验值对比验证了模型的准确性。分析了扩压室结构参数与喷射器膨胀比、喷嘴喉部直径和混合室直径之间的关系。结果表明,扩压室半锥角α随膨胀比pg/pe、扩压室出口直径与混合室出口直径之比dc/dc3以及喷嘴喉部直径与混合室直径之比dg0/dc3的增大而减小;扩压室长度Ld随膨胀比pg/pe、直径比dc/dc3及喷嘴喉部直径dg0的增大而增大,而随着混合室直径dc3的增大而减小或近似保持不变。

The diffuser chamber has an important influence on the speed decreasing and pressure lifting of the mixed fluid in the ejector.Based on the physical properties of real fluid,a modified onedimensional mixing model is established by means of the gas dynamics method and the optimization method of the structure design of the diffuser chamber is proposed.The model accuracy is verified by comparing the calculation results with the experimental data from literatures.The analyses are performed on the relationship among the structural parameters of the diffuser chamber,the expansion ratio of the ejector,the diameter of the nozzle throat and the diameter of the mixing chamber.The results show that the half-conical angle a of the diffuser chamber decreases with the increase of the expansion ratio pg/pe.the diameter ratio of expanding chamber outlet to mixing chamber dc/dc3and the diameter ratio of nozzle throat to mixing chamber dg0/dc3.The diffuser chamber length Ld increases with the increase of the expansion ratio pg/pe,the diameter ratio dc/dc3 and the nozzle throat diameter dg0 while decreases or approximately remains the same with the increase of the mixing chamber diameter dc3.