“J”形燃油导管泄漏原因分析与结构优化

Analysis on Leaking of The J-Shaped Fuel Tube in Aircraft and Its Structure Optimization

针对生产过程中"J"形飞机燃油导管在其内部充压情况下的法兰区螺栓位置泄漏问题,在圆环坐标系下对导管弯头内壁的压力进行基于参数方程的曲面积分,分析泄漏原因并给出结构优化方案。分析结果显示,由于弯头内壁各向曲面面积差异,导致各向受力不能相互平衡,该非平衡力系的合力使得安装导管的单颗主受力螺栓伸长量过大,导管发生小角度旋转而在法兰区产生泄露。合力的大小与导管内径的平方成正比而与其弯头的回转半径无关。将法兰区的螺栓连接孔位置整体绕导管轴线旋转22.5°,导管安装螺栓的最大伸长量将降低46%,可有效解决导管充压泄漏问题。

In order to solve the leaking problem happened in the bolt position of flange area of the J-shaped fuel tube in aircraft which is subjected to inner pressure, the pressure on the elbow area of tube has been integrated using parameter equations expressed by ring coordinate system. The leaking mechanism has been analyzed and the optimization solution of the tube structure has been proposed. The results show that the differences of surface area in different direction of the tube elbow lead to non-equilibrium forces loaded on it. The resultant force of non-equilibrium forces lengthens one of the connecting bolts too much, which makes the tube rotate slightly and causes the leaking problem appeared in flange area. Magnitude of the resultant force is in direct proportion to inner radius square of the tube and is unrelated to elbow rotation radius. Rotating all of the connecting holes around the tube axis in 22.5°, the maximum elongation of connecting bolt decreases by 46%. The leaking problem of the J-shaped fuel tube can be solved.