| The frictional heat effects causes the temperature rise on the contact interface and form a non-uniform and unsteady temperature field in friction pair, thus exerting impact on tribological properties and resulting in a reduced service life of the mechanical components. Because the frictional heat generation and conduction are subject to many coupling factors, and the friction pairs are in contact with each other and in relative sliding, it is difficult to obtain transient temperature of the contact interface accurately with experiment or numerical calculation. Therefore, obtaining the transient temperature of sliding pair is a key issue in the tribological research.The topic of this dissertation is supported by the National Natural Science Fund "Reconstruction Method for the Three-Dimensional Temperature Field of the Friction Pair based on Infrared Thermograph". This dissertation focused on a further study of the method of obtaining the transient temperature on the grease-lubricated sliding contact interface of the end-face friction with the experiment and numerical calculation. The main contents of this dissertation contains:1) The construction scheme for the temperature field of frictional contact interface has been designed with measurement temperature information as the boundary conditions. The numerical calculation has been used for the research on the temperature distribution of annular contact interface during friction process in order to verify the feasibility of temperature measurement with average values instead of multi-point measurement. Meanwhile, infrared temperature measurement system has been developed and thermal insulation structure has been adopted for preventing the interference on infrared thermometer from thermal pulse.2) Besides, a method for research on the emissivity of grease lubricated contact interface with meso-low temperature has been proposed by means of contact interface brightness temperature and the outmost temperature of sliding contact interface. The dynamic change regularity of emissivity on the contact interface has been explored under five different experimental conditions, and achieved the initial correction of the corresponding sliding contact surface brightness temperature.3) The transient temperature field reconstruction of the contact interface has been achieved with the initial correction of the radiation brightness temperature as the boundary condition, and measurement lateral surface temperature of the lower sample by the infrared camera as the amended conditions. Meanwhile, the validity and correctness of the sliding contact interface transient temperature has been verified by means of a comparison between calculated and measured temperature of the lower sample.4) In addition, the evolution of the end face sliding friction temperature field has been discussed and it has been proved that lateral surface temperature of the sample has appeared uniform during friction. Therefore, the infrared thermometer can be used for measuring the average temperature instead of the thermal imager. With the measurement and calculation result reference to different material samples in the different experimental conditions, the linear regression equation on the temperature of contact interface, load, speed, friction coefficient and the lateral surface temperature of the lower sample has been established. Finally, a construction plan on the measurement system for the end face friction tester has been put forward.This dissertation has explored and studied the acquisition method for the transient temperature of the end-face sliding contact interface, and laid a foundation for researches on the relationship between material tribological properties and the temperature. |
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