| Summary: | 碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 98 === In this study, Reometer AR2000 is used to investigate the effect of shear rate on viscosity of emulsion. And a model for the effective viscosity of emulsion is established. Moreover, another model for the hydrodynamic lubrication with binary mixtures of non-Newton fluids is developed. The coupled modified Reynolds are solved by combining the advanced multilevel method with the Newton-Raphson method. The effect of shear rate on lubrication characteristics of hydrodynamic lubrication of emulsion is investigated in cold rolling process.
Research results show that the viscosity of emulsion is decreased with increasing the shear rate. Hence,the oil film thickness, oil preasure and oil concentration under hydrodynamic lubrication are increased with decreasing the slide-to roll ratio. Emulsion will be Newton fluid under high shear rate. In the cold rolling process, the emulsion shows the high shear rate, and the elastic deformation of roller and strip are considersd. Hence the end point of plastic zone of strip is moved to oulet zone due to the lubricated zone is increased, so that the film thickness is higher than that for rigid body. When roller radius is increased, the effective elastic modulus and the thickness reduction of strip are decreased, then the lubrication characteristics in cold rolling process are influenced by elastic deformation. When the rolling speed is increased , the inlet film thickness is increased, and the roll torque is slightly increased, but the rolling force and peak preasure are almost not influenced.
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