Texture Shape Optimization And Performance Analysis Based On JFO Cavitation Boundary Conditions

Surface texture refers to the processing of a certain size,shape and arrangement of patterns on the surface of a material through a certain processing technology.As a surface technology that can effectively reduce friction,it has been widely concerned and studied by relevant scholars.In surface texture technology,texture shape has a very important effect on friction and lubrication properties.In recent years,a large number of researches on texture shapes have laid a good foundation for the application of texture.However,most researches assume specific regular shapes to carry out relevant researches and comparative analysis,and fail to reflect the idea of active optimization design.Therefore,how to obtain the optimal texture shape suitable for specific working conditions based on the composition of the texture itself needs further exploration.In order to comprehensively explore the variation law of parameters related to the optimal texture shape with different working conditions,based on JFO(Jakobsson-Floberg-Olsson)cavitation boundary conditions,optimization evaluation parameters were selected,and a texture optimization mathematical model was established by solving the governing equation and combining with genetic algorithm.The change rule of texture shape under fluid lubrication and mixed lubrication conditions is studied,and the change rule of the optimal texture shape and tribological properties under parallel plane and non-parallel plane is discussed.The main contents and conclusions are as follows:1.Study on optimal texture shape of parallel surfaces under fluid lubrication conditions:Taking load-carrying capacity as evaluation parameter,Reynolds equation is selected and solved to establish texture shape optimization model.The simplification of the optimization model and characterization parameters related to texture shape are studied with the end distance of friction pair,sliding velocity and cavitation pressure,and are compared with the best microporous texture.The results show that the load load-carrying and tribological properties of the optimal texture are better than those of the optimal microporous texture,especially when the distance between the end faces of the friction pair is small and the sliding speed is large,the performance improvement is more significant.When the area ratio is not restricted or restricted,the optimal texture shape is the herringbone shape with flat front.The optimal texture shape change can be represented by using the horizontal coordinate of two points on the liquid inflow side as the design variable.By comparing the friction coefficient of the specimen with the optimal texture,microporous texture and non-texture,it is found that the friction coefficient can be effectively reduced by processing the texture on the surface of the specimen,and the friction coefficient of the specimen with the optimal texture shape is the lowest,which verifies the correctness of the theoretical model and the results.2.Study on optimal texture shape of non-parallel surface under fluid lubrication:According to the parallel surface study,the size of fluid inlet and outlet is changed,and the texture shape optimization model of the non-parallel surface is established.The influences of inclination Angle,the distance between the end faces of friction pairs,sliding velocity and cavitation pressure on the texture shape and tribological properties are analyzed comprehensively,and the results are compared with the optimal microporous texture loadcarrying properties to verify the effectiveness of the optimization.The results show that,without limiting the area ratio,the optimal texture is a flat pocket shape at the front,which is mainly distributed in the inflow side of the liquid,and its shape characterization parameters almost do not change with the variation of the working condition parameters.When the restricted area ratio(AR)is less than or equal to 20%,the optimal texture shape is V-shaped with flat tail,and the optimal area ratio is 20%.The load-carrying capacity of the non-parallel surface of the optimal texture shape decreases with the increase of the distance between the inclination Angle and the end face of the friction pair.With the increase of sliding velocity,the load-carrying capacity increases.With the increase of cavitation pressure,the load-carrying capacity changes little.The optimal texture has better load-carrying performance than the optimal microporous texture,especially under the conditions of small inclination Angle,small distance between the end faces of friction pairs and large sliding speed.3.Study on optimal texture shape of parallel surface under mixed lubrication condition:The average Reynolds equation is selected and solved,and the texture shape optimization model is established by combining with genetic algorithm and aiming at the minimum friction coefficient.The influence of roughness parameters and different working conditions on the optimal texture shape and its tribological properties is explored.The effectiveness of optimization is verified by comparing the frictional performance of the best microporous texture and the optimal texture shape under different working conditions.The results show that,compared with smooth parallel surfaces,the optimal texture shape area ratio(AR)is about 80%when the area ratio is not limited.When the restricted area ratio(AR)is less than or equal to20%,the optimal texture shape is herringbone or V-shaped shape.In the calculation domain,the flat front end of herringbone texture can increase the high pressure distribution area in the calculation domain,while the V-shaped texture can increase the maximum pressure in the calculation domain.