Boundary Heat Flux Inversion And Temperature Field Reconstruction Of Dry Clutch Friction Plate

Dry clutches are widely used in the automotive industry and their primary function is to transfer engine power to the transmission.During the engagement of the clutch,the friction of the main and follower causes the temperature of the friction disc to rise.The thermal stress generated by the high temperature may cause deformation,cracks,etc.of the friction material,causing the clutch to frustrate,the transmission efficiency to decrease or even fail.Optimizing the clutch material selection,structural design and control strategy by studying the clutch temperature field is of great significance for improving clutch performance and service life.At present,the research on the clutch temperature field is mainly solved by numerical simulation method.Because the sliding friction is difficult to calculate accurately and the heat flux distribution coefficient is not uniform,the accurate calculation of the boundary heat flux of the friction disk is very difficult,and the temperature field solution has errors.The Inverse Heat Transfer Problem(IHTP)is an unknown information such as the thermal boundary conditions,geometry,heat source intensity,and thermal property parameters of the heat transfer system from the partial temperature measurement information of the system.According to the temperature information of some measuring points in the friction disc,using IHTP to accurately invert the surface heat flux and reconstruct the temperature field is a solution different from the traditional clutch temperature field.In this paper,the Sequential Function Specification Method(SFSM)is used to invert the friction disk boundary heat flux during clutch engagement.The main contents are as follows:(1)This paper discusses the engineering research background of the subject,and summarizes the research on the clutch temperature field at home and abroad.The two-dimensional unsteady heat transfer model of the friction disc during the clutch engagement process is established.The temperature distribution of the friction disc under different torque input conditions was simulated by numerical experiments.The test results were analyzed and compared with the literature results to verify the correctness of the model.And verified the independence of meshing.(2)The basic theory of IHTP and the main research methods are expounded.The basic concepts and principles of SFSM are introduced.The SFSM-based friction disk boundary heat flux inversion model is established and the optimization of future time steps is discussed.(3)The inversion of the heat flux on the surface of the friction disc under different working conditions was simulated.Based on this,the temperature field of the friction disc was reconstructed.The influence of the position of the measuring point,the temperature measurement error and the future time step on the inversion effect are studied.The experimental results show that the inversion model based on SFSM can effectively invert the boundary heat flux of the friction disc;For materials with a small thermal conductivity,increase the distance between the measuring point and the inversion point,and the inversion result will be significantly worse.;The measurement error is within a certain range,and the inversion and reconstruction results are better.The increase of measurement error will significantly reduce the inversion effect;When the value of the future time step is small,the algorithm is more sensitive to the measurement error,increasing the future time step,which can effectively enhance the suppression of the measurement error,but at the same time the accuracy of the algorithm will be reduced,therefore,choosing the right future time step is very important to get the inversion effect that meets the requirements.