| The hydrodynamic lubricating elastic metal-plastic bearing,commonly known as the bearing,plays a crucial role in maintaining the stability of the shaft system during the operation of large-scale water pumps at the four stations in Huai’an.However,the polytetrafluoroethylene(PTFE)shaft liner has low hardness and elastic modulus,and the bearing is lubricated directly by river water,which contains a high concentration of sediment.This makes the bearing prone to wear and deformation,resulting in changes in the thickness of the micron-level lubricating film and a significant impact on the lubrication performance of the bearing.In addition,the stiffness and damping of the bearing have a significant impact on the operational performance of large-scale water pumps.Insufficient stiffness and damping can increase vibration and noise during the operation of the bearing,weaken the bearing’s ability to resist external interference,and ultimately lead to bearing failure.In severe cases,this can result in the water pump being unable to operate properly.Therefore,it is essential to conduct an in-depth study of the fluid-solid coupling characteristics and dynamic characteristics of the bearings in large-scale water pumps at the four stations in Huai’an.The main research content of this paper is as follows:(1)The Effect of Structural Parameters on the Fluid-Solid Coupling Characteristics of Journal Bearings.The fluid-solid coupling characteristics of journal bearings were investigated using the Fluent fluid module,Transient Structural solid module,and System Coupling coupling module in ANSYS Workbench software.The influence of different attitude angles,radius clearances,groove widths,groove depths,and groove numbers on the fluid-solid coupling characteristics of journal bearings was analyzed,including the lubrication film pressure,bushing deformation,bushing equivalent stress,load capacity,friction force,and friction coefficient.The results indicate that,with the same conditions of radial clearance and eccentricity,the effect of the offset angle on the flow-solid coupling characteristics of the journal bearing is negligible.With the same minimum film thickness,as the radial clearance increases,the circumferential gradient of the lubrication film pressure increases,the maximum deformation of the bushing increases,and the maximum equivalent stress of the bushing first increases and then decreases.Furthermore,the load capacity and friction force increase,while the friction coefficient decreases.With the same eccentricity conditions,as the groove width,depth,and number increase,the circumferential gradient of the lubrication film pressure decreases,the maximum deformation of the bushing decreases,and the variation law of the equivalent stress of the bushing is inconsistent.In addition,the load capacity and friction force decrease,while the friction coefficient increases.(2)The influence of uniform and local wear on the flow-solid coupling characteristics of journal bearings.Study the effects of uniform wear and local wear on the fluid-solid coupling characteristics of journal bearings.The results indicate that,under uniform wear conditions,as the maximum wear increases,the circumferential gradient of the overall lubrication film pressure decreases sharply,the area of high deformation decreases,the distribution of equivalent stress becomes uneven and concentrated,the load capacity decreases,the friction force decreases,and the friction coefficient increases.Under local wear conditions,if the local wear occurs at the minimum clearance,the hydrodynamic lubrication film cannot be formed,the deformation distribution is no longer regular,and the maximum deformation is concentrated at the depression of the local wear.When local wear occurs at the middle or maximum clearance,the influence on the hydrodynamic lubrication effect is relatively small.It should be noted that the existence of local wear will cause a sudden drop in the equivalent stress on the surface of the bearing,a sharp increase in the equivalent stress at the groove near the bearing,and an increase in load capacity and friction force,while reducing the friction coefficient.Among them,when local wear occurs at the minimum clearance,the load capacity and friction force are maximum,and the friction coefficient is minimum.(3)Influence of Different Operating Conditions on the Dynamic Characteristics of Journal Bearings.Based on Fluent’s dynamic mesh technology,a UDF is developed to define the trajectory of the center of the journal bearings for studying the dynamic characteristics of the journal bearings.The effects of different eccentricity ratios,radial clearances,disturbance amplitudes,and disturbance frequencies on the dynamic coefficients of the journal bearings,including the stiffness and damping coefficients,are analyzed.The results show that as the eccentricity increases,the absolute values of direct stiffness coefficients KXX and cross stiffness coefficients KXY decrease,while the absolute value of direct stiffness coefficient KYY,cross stiffness coefficient KYX,direct damping coefficient CXX,direct damping coefficient CYY,and cross damping coefficient CYX increase.With the increase of the radius clearance,the absolute values of the direct stiffness coefficient KXX and the cross stiffness coefficient first decrease and then increase,the absolute value of the direct stiffness coefficient KYY increases,while the cross stiffness coefficient KYX,the direct damping coefficient CXX,the direct damping coefficient CYY and the two cross damping coefficients CXY and CYX decrease.When the disturbance amplitude is less than or equal to 0.009,the stiffness and damping coefficients remain almost unchanged as the disturbance amplitude increases.With the disturbance frequency increases,the stiffness coefficients remain almost unchanged.The absolute values of direct damping coefficients CXX and CYY decrease,while the cross damping coefficient CXY increases and the cross damping coefficient CYX decreases. |
