| 摘要:以某中速机第3档主轴瓦气蚀损伤为研究对象，揭示其形成机理并提出优化方案，并基于Flomaster软件构建一维CFD模型，仿真显示主轴颈压力波动幅度达0.78 MPa，负压区（0.24 MPa）直接导致气泡生成并在曲轴旋转过程中溃灭，形成典型“双肾形”气蚀损伤斑块。针对此问题，提出4项改进措施：将主轴颈油孔直径扩展至36 mm，消除油路突扩导致的压力骤降；轴瓦油槽弧度增至25°，提升压力波动下限；将磨合层材料更换为抗气蚀性更强的SnSb11Cu4；优化电镀工艺并采用平板电镀瓦。试验验证表明，改进后气蚀损伤显著缓解，第3档主轴瓦下瓦气蚀完全消除。研究指出，轴瓦气蚀防控需协同优化流体参数与材料性能，规避油路突扩设计，并优先通过结构改进稳定压力波动。 |
| 关键词: 发动机 轴瓦 压力波动 空化气蚀 |
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| Cavitation Control of Bearing Shell of a Large Medium-Speed Engine |
| Zhang Dongxing,Tu Danhong,Niu Junjun,Ning Peng |
| China Shipbuilding Power Engineering Institute Co.，Ltd.， Shanghai 201208， China |
| Abstract:The study investigated the cavitation erosion damage of the third gear main bearing in a medium-speed engine，revealing its formation mechanism and proposing optimization strategies.A one-dimensional CFD model constructed via Flomaster demonstrated that the pressure fluctuation amplitude of the main journal reached 0.78 MPa， with a negative pressure zone（0.24 MPa）directly causing bubble generation and collapse during crankshaft rotation，forming typical "double kidney-shaped" cavitation erosion lesions.Four improvement measures were implemented：enlarging the main journal oil hole diameter to 36 mm to eliminate pressure drops caused by sudden oil passage expansion；increasing the oil groove curvature to 25° to raise the pressure fluctuation lower limit；substituting the running-in layer material with SnSb11Cu4 for enhanced anti-cavitation performance；and optimizing electroplating processes through flat electroplating bushing.Experimental validation confirmed significant cavitation mitigation，with complete elimination observed in the lower bushing of the third gear main bearing. These findings emphasize that effective cavitation control in bearings requires coordinated optimization of fluid dynamics and material properties，avoidance of sudden oil passage expansions，and structural modifications to stabilize pressure fluctuations. |
| Key words: engine bearing shell pressure fluctuation cavitation erosion |
