液压油箱回油流场气泡析出的数值仿真与实验验证

Simulation and Experimental Verification of Bubble Release in the Return Oil Field of Hydraulic Tank

液压油箱回油管有置于液面之上和液面之下两种方式,易造成不同程度的气泡析出,从而影响飞机液压系统的性能和可靠性。为此,利用k-ω SST两方程模型针对两种方式进行回油流场气泡析出的数值模拟,仿真研究气泡在油液油箱内的流动与分布规律。结果表明,前者随液面高度的增加气泡越集中聚集,其气体体积分数就越大,且油液上表面的气体体积分数最大可达12.35%,而油箱底部气泡含量最低仅为0.512%;后者气泡聚集分布规律与前者相似,油液上表面的气泡体积分数最大为9.57%,油箱底部气泡含量最低仅为0.056%,相较前者最高和最低体积分数都减少了,且油箱吸油口截面处的气泡体积分数显著减少。最后,实验验证了仿真的正确性,可为油箱新构型的设计提供参考。

The hydraulic oil tank return pipe can be placed above the liquid level and below the liquid level in two ways,which is easy to cause different degrees of bubble precipitation,thus affecting the performance and reliability of the aircraft hydraulic system.The bubble release in the return oil field of hydraulic tank is simulated by using k-ω SST model,then the flow and distribution of bubbles in the oil tank are compared and analyzed when the hydraulic return pipe is placed above and below the hydraulic oil tank level.The research shows that when the pipe is placed above the hydraulic oil tank level,with the increase of hydraulic oil tank evel,the more concentrated the bubbles are,the larger the bubble volume fraction is,the maximum fraction of bubble volume on the upper surface is 12.35% and the lowest bubble volume fraction at the bottom of the tank is 0.512%.When the pipe is inserted below the hydraulic tank level,the distribution of bubble accumulation is similar to the former,the maximum fraction of bubble volume on the upper surface of the bubble is 9.57% and the lowest bubble volume fraction in the oil domain is 0.056% at the bottom of the tank.The bubble volume fraction above the oil tank and at the suction section of the oil tank decreases significantly when the return pipe reaches below the liquid level of the oil tank.The experimental results validate the numerical simulation value.