基于热-电法的船用柴油机主轴承磨损监测方法研究

The excessive wear of main journal bearings of a marine diesel engine would lead to severe failures of flexural deflection, scuff, even fracture, therefore it is of importance to on-line monitor the wear condition of main bearings. A technical route combining theoretical analysis and experimental research will be adopted in the project to investigate the change mechanism of the thermoelectric power caused by the wear of main bearings, so as to obtain a novel methodology of monitoring wear condition based on the thermoelectricity technology. The theoretical analysis mainly includes building, optimizing, and verifying a FE model of the main journal-lubricating oil film-main bearing-heat-thermoelectric power, so that the discipline between wear condition and thermoelectricity power can be obtained; the experimental research mainly includes building a special test-bed to conduct different bearing wear condition simulated experiments, developing a device to get, condition and amplify the weak thermoelectricity signal, designing a signal processing method to extract the feature value related to the wear condition, and carrying on some proving trials. The main objective of this project is to investigate the changing discipline between wear condition of main journal bearings and thermoelectricity power, to grasp the theory and experimental methods of thermoelectricity produced by main bearings, and eventually to lay the foundation for the application of thermoelectricity method for on-line monitoring the wear condition of main bearings of marine diesel engines.

船用柴油机主轴承过度磨损将引起曲轴挠曲变形和抱熔折断等恶性事故的发生，在线监测主轴承磨损量是船用柴油机的重要研究课题之一。项目研究拟采用理论分析与试验相结合的技术路线，分析柴油机主轴承与主轴颈摩擦产生热电势机理，研究基于热-电法的船用柴油机主轴承磨损监测方法。理论研究包括：主轴颈-润滑油膜-主轴承-热量-热电势模型建立，模型假设合理性分析和模型修正，计算与试验结果的一致性分析，不同主轴承磨损产生热量引起的温度升高与热电势的变化规律。试验研究包括：柴油机主轴承磨损试验台搭建，主轴承不同磨损量模拟试验，热-电信号引出装置研制，热-电信号抗干扰、滤波和特征量提取，船用柴油机典型工况试验验证。通过研究揭示柴油机主轴承磨损生热产生温度升高与热电势的变化规律，掌握主轴承磨损-温升-电势的测量原理与试验方法，为实现基于热-电法的船用柴油机主轴承磨损在线监测方法的工程应用奠定基础。

曲轴和主轴承是柴油机的主要摩擦副之一，曲轴在运动过程中受力复杂，在柴油机工作循环中呈周期性变化的交变载荷作用下，主轴承易发热和磨损，主轴承过度磨损将引起曲轴挠曲变形和抱熔折断等恶性事故的发生，在线监测主轴承磨损量是船用柴油机的重要研究课题之一。本项目采用理论计算分析与试验相结合研究路线，分析柴油机主轴承与主轴颈摩擦产生热电势机理，研究基于热-电法的船用柴油机主轴承磨损监测方法。理论研究包括：主轴颈-润滑油膜-主轴承-热量-热电势建模及计算，分析柴油机不同主轴承磨损产生热量引起的温度升高与热电势的变化规律。试验研究包括：研制热-电信号引出装置，开发主轴承磨损-温升-电势测量系统；搭建主轴承磨损试验台，主轴承不同磨损量模拟试验；柴油机典型工况主轴承磨损状态的试验验证。通过研究揭示了柴油机主轴承磨损生热产生温度升高与热电势的变化规律，掌握了主轴承磨损-温升-电势的测量原理与试验方法，证实了基于热电法的船舶柴油机活塞环磨损监测方法的有效性。