Study On The Thermal Characteristics Of The Spool With U-shaped Groove

Hydraulic slide valve,as a typical hydraulic control element,is also the main component of the system failure.The micro deformation caused by the internal thermal load leads to the valve clamping stagnation which is one of the common failures Therefore,it has a very important value and significance to understand the essence of reliability of hydraulic slide valve and reveal the valve clamping stagnation phenomenon in micron scale.This paper uses the method of coupling of multi physics field and based on computational fluid dynamic and computational structure dynamic.With the help of Fluent software and ABAQUS software,the fluid-solid-thermal coupling calculation of U groove valve is carried out,and the influence of opening of valve port,pressure of valve port and flow of valve port on its thermal characteristics is emphatically studied.The analysis shows that due to the viscous effect of the oil,the area decreases suddenly after passing through the valve port,which results in the instantaneous increase of flow velocity,accompanied by a large number of vortices,and finally the temperature of oil has risen.The temperature of the valve spool is gradually increased under the action of high temperature oil.In the end,the expansion and deformation of spool has occurred under the effect of thermal load and stress,which result in the stagnation of the slide valve.The main contents of this paper are as follows:In the first chapter,the importance of the hydraulic slide valve in the engineering machinery and the cause of the failure are introduced;The spool valve with grooves and its clamping stagnation are summarized;The research status of the thermal-mechanical coupling of the sliding valve and the status of the valve port characteristics are described.In the second chapter,the multi physical field coupling subject is introduced,and the calculation process of the fluid-solid-thermal coupling and the theoretical methods are analyzed.Based on the valve port characteristics of the groove,the area of the U-shaped groove is derived and the calculation software for the area of the valve port is designed.In the third chapter,the physical properties of the viscosity of hydraulic oil are introduced,and the calculation model is set up to simulate.The flow field of the sliding valve under the different opening and pressure of the valve port are analyzed,including the velocity field,pressure field and temperature field of the oil.It lays the foundation for the study of the temperature distribution of the valve spool.In the fourth chapter,the thermal physical properties of solid materials are summarized.The structure field of the sliding valve under the different opening and pressure of the valve port are analyzed,including the temperature field,the stress-strain field and the deformation field of the valve spool.The results show that the spool is inflated under the action of thermal load,and the deformation increases with the increase of the pressure difference of the valve port,and increases first and then decreases with the increase of valve opening.In the fifth chapter,the effect of valve port flow on the thermal characteristics of slide valve is studied.In fixed opening and under the same working condition,flow field and valve spool of sliding valve are calculated about groove number,groove size,groove width and groove depth.In the sixth chapter,the device for measuring the temperature field and deformation field of spool valve is developed,and the temperature and deformation of the U-shaped groove are measured.The thesis proposes research methods about thermal characteristics of hydraulic spool valve for U-shaped groove,lays a great theoretical and technological basis for further thermal characteristics analysis of the hydraulic system,and provides basis for the design and optimization of the structure and shape of the slide valve with U-shaped grooves.