基于替代燃料的航空燃油泵内部空化特性

Cavitation characteristic in aviation fuel pump based on surrogate fuel

为了研究以国产大庆RP-3航空煤油为流动介质的航空燃油泵内部空化特性,采用数值模拟的方法研究了高温低压环境下航空燃油泵内部的空化流动.针对航空煤油这种成分复杂的介质,引入替代燃料的概念,选择摩尔分数为74.5%的正十二烷、10%的甲基环已烷、10%的甲苯和5.5%的辛烷构成的四组分替代燃料模拟大庆RP-3航空煤油.计算中采用基于旋转修正的k-ε湍流模型以及Zwart-Gerber-Belamri空化模型,基于实验结果对数值方法进行了验证分析.研究结果表明:基于替代燃料和旋转修正的k-ε湍流模型的数值计算方法能够较准确地预测航空燃油泵的空化特性;忽略大庆RP-3航空煤油空化热力学效应,温度对航空燃油泵空化性能有一定影响,在80℃工况下,航空燃油泵空化性能较差;转速对航空燃油泵空化性能影响较大,航空燃油泵在转速为10 000r/min工况下空化比转速最大,空化性能最好.

To study the cavitation characteristic in an aviation fuel pump with China Daqing RP-3 kerosene as flowing medium, the cavitating flows in the aviation fuel pump un- der high temperature and low pressure circumstance were researched based on the numerical simulations. Surrogate fuel was put forward to take the place of the kerosene in the complex components. A four-species surrogate fuel consisting in mole fraction of 74. 5% dodecane, 10% methylcyclohexane, 10% toluene and 5.5% octane was selected to simulate the real Daqing RP-3 kerosene. Local swirling correction turbulence model derived from the standard k-e two-equation model and Zwart-Gerber-Belamri cavitation model were applied into the nu- merical simulations. The numerical data were compared with the experimental results. The results show that this numerical method based on surrogate fuel and local swirling correction turbulence model can calculate the cavitation characteristic in the aviation fuel pump accu-rately. Thermodynamic effects of Daqing RP-3 kerosene can be ignored, but the temperature has an influence on cavitation characteristic of the aviation fuel pump. The cavitation charac- teristic of the aviation fuel pump is worse under 80 ℃. Rotational speed has a great influence on cavitation characteristic of the aviation fuel pump. The cavitation specific speed is the highest under 10000r/min, and the cavitation characteristic is the best.