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泵的气蚀柔性代表由泵入口复杂气蚀过程所形成的气泡的液体压缩性。这一“气泡”柔性对确定火箭发动机动力谐振频率是一个重要因素,此外,它对运载火箭POGO稳定性分析也是一定要知道的一个因素。现在已经根据一些火箭涡轮泵的脉动试验确定了气蚀柔性。本文研究所用的主要试验数据是土星火箭上用的洛克达因(Rocketdyne)公司的H-1、F-1和J-2氧化剂及燃料泵的那些数据。研究表明,这些数据可以通过一个特殊的无因次化关系式而相互联系起来,其主要特点是把工作气蚀数或抽吸比速除以压头断裂(breakdown)时的气蚀数或抽吸比速。过去的研究结论是,由于没有采用压头断裂的形式,因此,不可能具有这样的关系式。现对这些数据可用一最佳拟合曲线得出关系式。对航空喷气(Aeroject)公司的LR87和91泵的另一组试验数据,可以通过一个稍微不同的泵无因次性能参数表达,尤其是可以通过气蚀数与其在压头断裂点和压头系数对气蚀数零斜率点之间的位置相关来表达。与气蚀柔性有关的数学模型的研究是成功的。所做的假设是,任何泵工作点的气泡容积与同压头断裂有关的无因次性能参数方幂成比例。本文给出的气蚀柔性的估算建议用于洛克达因公司泵系的最新设计。
The cavitation flexibility of the pump represents the liquid compressibility of the bubble formed by the complex cavitation process at the pump inlet. This “bubble” flexibility is an important factor in determining the rocket motor resonance frequency. In addition, it is also a factor that must be known for the launch vehicle POGO stability analysis. Cavitation flexibility has now been determined based on the pulsation tests of some rocket turbo pumps. The main experimental data used in this study is those of Rocketdyne’s H-1, F-1 and J-2 oxidizers and fuel pumps used on Saturn rockets. Studies have shown that these data can be related to each other through a special dimensionless relationship, the main characteristic is the number of work cavitation or suction ratio divided by the number of cavitation erosion or pumping Suction rate. It has been concluded in the past that it is not possible to have such a relation since the form of rupture of the indenter is not used. A best fit curve is now available for these data to arrive at the relationship. Another set of experimental data for Aeroject’s LR87 and 91 pumps can be expressed by a slightly different pump-dimensional dimensionless performance parameter, especially by the number of cavitations and their correlations at the head and head Express the position correlation between the points of zero slope of the cavitation. The research on mathematical models related to cavitation erosion has been successful. The assumption made is that the bubble volume at any pump operating point is proportional to the power of the dimensionless performance parameter associated with the fracture of the head. The estimation of cavitation flexibility given in this paper is recommended for the latest design of Lockhart’s pump division.