船舶尾轴机械密封面形状对密封性能的影响
Influence of mechanical sealing surface shape of marine stern shaft on sealing performance

针对船舶轴系轴线弯曲、轴系不对中、尾轴承磨损、螺旋桨水动力等多种因素导致的船舶尾轴机械密封性能不稳定问题,应用经验公式与ANSYS有限元法,研究了球面与平面2种密封面形状对密封性能的影响规律。在水深为200、400、600 m情况下,分别建立了球面与平面密封面的热-结构耦合模型,比较了2种机械密封的密封面接触面积、泄漏量、密封准数与单位面积摩擦功,分析了2种机械密封面形状对变形、接触压力与温度等关键参数的影响规律。研究结果表明:相同水深下,球面密封的间隙区域与最大间隙均小于平面密封,球面密封接触压力变化较平面密封平缓,其最大接触压力仅为平面密封的40%～50%; 随水深的增加,2种密封面的接触压力、温度与变形均增大,密封面的接触区域缩小,间隙区域不断扩大; 当水深由200 m增加到600 m时,球面密封的接触节点由10个减少为6个,平面密封的接触节点由7个减少为4个; 当水深为200 m时,球面密封面的最高温度比平面密封面低5.499 ℃; 球面密封的接触面积、泄漏量、密封准数与单位面积摩擦功均优于平面密封。可见,球形密封能够提高船舶尾轴机械密封性能。
In allusion to the unstable performance of marine stern shaft mechanical seal caused by the factors such as marine shaft axis bending, shaft misalignment, the wear of stern bearing, the force of propeller, etc., the influence laws of both spherical and planar sealing surface shapes on sealing performance were researched by using both empirical formula and ANSYS finite element method. When water depths are 200, 400, 600 m, the thermal-structural coupling models of both spherical and planar sealing surface were established respectively. The contact areas, the leakage rates, the seal criterias, and the friction powers of unit area were compared, and the influence laws of both spherical and planar sealing surface shapes on the key parameters such as deformation, contact pressure, and temperature, etc., were discussed. Analysis result shows that under the same water depth, the clearance region and the maximum clearance of spherical seal are less than the values of planar seal. Compared to planar seal, the contact pressure of spherical seal changes more smoothly, and the maximum contact pressure of spherical seal is only 40%-50% of the pressure of planar seal. With the increasing of water depth, the contact pressure, temperature, and deformation of the two kinds of sealing surfaces increase, the contact region of sealing surface decrease, the clearance region extends gradually. When water depth increases from 200 m to 600 m, the contact node number of spherical seal decreases from 10 to 6, and the number of planar seal decreases from 7 to 4. When water depth is 200 m, the maximum temperature of spherical sealing surface is 5.499 ℃ lower than the value of planar sealing surface. The contact area, leakage rate, seal criteria, and the friction power of unit area of spherical seal are all better than the parameters of planar seal, so the spherical seal can improve the mechanical sealing performance of marine stern shaft. 2 tabs, 9 figs, 25 refs