超临界RP-3航空煤油喷嘴内部流动与相变特性研究

未来航空燃气轮机采用燃油作为冷却剂,对发动机冷却空气及热端部件进行冷却,使得燃油在进入燃烧室之前超过其热力学临界点,燃油的热力学性质发生巨大变化,将对燃油在喷嘴内的流动和喷嘴下游的喷射掺混过程产生重要的影响,因此有必要对超临界RP-3在喷嘴内的流动与相变特性展开研究。本文采用自主设计的喷嘴内部收缩通道模拟试验件,对超临界RP-3在喷嘴内的沿程压力分布进行测量,并采用基于一维等熵假设的计算方法进行数值模拟。试验首次获得了超临界航空煤油RP-3在喷嘴收缩通道内的沿程静压分布随喷射压力、温度变化的规律。通过与模型对比,发现未发生相变时,计算结果与试验值拟合精度较高,可以较好地预测RP-3在喷嘴内的流动参数,喷嘴内的静压分布也趋于一致；发生冷凝相变时,计算结果与试验值产生误差较大,喷射参数对于静压分布存在着较大的影响。本文试验获得的超临界RP-3航空煤油在喷嘴内的流动与相变特性,为航空发动机超临界RP-3喷射的喷嘴设计提供了重要的设计依据。

Flow and Phase Transition Characteristics of Supercritical RP-3 Aviation Kerosene in Injector

For advanced aeroengine, the self-cooling technology uses fuel as coolant, resulting in fuel heated beyond its thermodynamic critical point before entering the combustion chamber. The thermodynamic properties of fuel change greatly, which will have an important influence on the fuel flow in the injector and the injection mixing process downstream of the injector. Therefore, it is necessary to study the flow and phase transition characteristics of supercritical RP-3 in the injector. In this paper, the parameters along the injector of supercritical RP-3 are measured by using a self-designed simulation test piece of injector contraction channel. Numerical simulation was carried out by using one-dimensional isentropic calculation method. The static pressure distribution of supercritical aviation kerosene RP-3 in the nozzle shrinkage channel varies with the injection pressure temperature. By comparing with the model, it is found that without phase transition, the fitting accuracy of the calculated results and the experimental values is relatively high, and the flow parameters of RP-3 in the nozzle can be well predicted, and the static pressure distribution in the nozzle tends to be consistent. When the condensation phase transition occurs, the differencse between the calculated results and the experimental values are large, and the injection parameters have a great influence on the static pressure distribution. The flow and phase transition characteristics of RP-3 injection obtained in this paper provide a fundamental understanding of supercritical injection for hydrocarbon fuels and can be used for better development of supercritical injectors in aviation applications.