| As a kind of processing equipment of rubber products,the mixer plays an important role in the process of rubber mixing.In order to further improve the performance of the end face sealing device of the mixer and reduce the leakage of material and powder in the gap between the rotor and the side wall of the mixer,a composite microporous texture was designed on the end face sealing surface of the mixer,and the textured end face sealing device was studied.The research contents are as follows:(1)The hydrodynamic lubrication model of the end face sealing device of the complex microporous textured refiner was established and the performance of five different shapes of the end face sealing device of the complex textured refiner was compared and analyzed.The results show that the Circle-ellipse⊥perp composite texture has the best sealing performance,and the bearing capacity and friction performance are the highest when the texture depth is 4-6μm.Increasing the area ratio of the texture enhances the hydrodynamic pressure effect and decreases the friction coefficient.When the area ratio of the texture is 50.24%,the average dimensionless pressure is the maximum and the friction coefficient is the minimum.With the increase of seal clearance,the average dimensionless pressure and friction coefficient of the Circle-ellipse⊥orthogonal composite texture decrease on the whole under different working conditions.When the seal clearance is greater than 5μm,the composite texture only plays the role of lubricating oil storage and no longer produces hydrodynamic pressure effect.Increasing the rotor speed and lubricating oil viscosity is beneficial to increase the average dimensionless pressure of seal end face and reduce the friction.The average dimensionless pressure and friction coefficient vary with the texture parameters and working conditions under different configuration modes of Circle-ellipse⊥orthogonal composite texture.(2)Based on the theoretical model of Circle-ellipse⊥orthogonal composite microporous texture,the effects of the composite texture parameters and working conditions on the sealing performance of the end face sealing device of the mixer were analyzed.The results show that increasing the texture depth is beneficial to improve the sealing performance of the end face sealing device and reduce the leakage rate.With the increase of texture area ratio and rotor speed,the leakage amount and oil film stiffness of seal end face increase gradually,and the rigid-to-leakage ratio decreases gradually.The increase of lubricating oil viscosity leads to the gradual increase of leakage and rigor leakage ratio,which intensifies the degree of leakage of the mixer;When the sealing gap increases,the oil film stiffness and rigid-leakage ratio decrease rapidly and then gradually stabilize.When the sealing gap exceeds a certain value,the sealing performance of the end face sealing device is no longer affected.With the increase of texture depth,the leakage and film stiffness of the end face seal surface first increase and then decrease.With the increase of texture area ratio,rotor speed and lubricating oil viscosity,the leakage amount and oil film stiffness of seal end face gradually increase,which not only improves the resistance ability of seal end face,but also increases the leakage rate.When the sealing gap is increased,the oil film stiffness and rigid-to-leakage ratio are reduced,and the leakage amount is increased.Choosing a smaller sealing gap will improve the sealing performance of the end face sealing device of the mixer.(3)A theoretical model of the Circle-ellipse⊥orthogonal compound textured end sealing device of the mixer considering surface roughness was established,and the effect of roughness on the performance of the end sealing device was studied.The results show that the seal clearance,the maximum oil film pressure and the leakage amount have obvious changes with the increase of the comprehensive roughness.With the increase of directional parameters,there are obvious differences among the performance indexes.Reasonable selection of directional parameters can make the composite textured end face sealing device of the mixer have better friction and sealing performance.Under different roughness parameters,with the increase of texture depth and texture area ratio,the friction coefficient,the maximum oil film pressure and the seal clearance,the leakage amount formed an opposite trend.Under the condition of the same other parameters,the appropriate increase of the composite texture parameters can reduce the friction and wear and prolong the service life of the mixer.(4)Different working parameters and complex micro-texture parameters were selected,and the TRB~3 friction and wear testing machine was used to carry out the pin-disk orthogonal test.In the orthogonal experiment,the intuitive analysis method shows that the average friction coefficient of the texture of the Circle-ellipse⊥orthogonal compound is the lowest when the load P=1N,the rotation speed n=55r/min,the texture depth h_p=2μm,and the texture area rate S_p=18.84%,and the range analysis method shows that P=2N,n=65r/min,h_p=2μm,S_p=18.84%,the friction properties of the Circle-ellipse⊥orthogonal composite texture are optimal,and the texture depth has the greatest influence on the friction performance of the end face sealing device. |
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