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Investigation of fluid flow and heat transfer in grinding
In this dissertation, comprehensive thermal models are developed to account for the influence of grinding conditions on the temperatures generated. Various aspects of the heat transfer problem are analyzed and experimentally investigated including the fluid flow through the grinding zone, energy partition to the workpiece, heat flux distribution at the workpiece surface, cooling by the grinding fluid, transient temperatures during a grinding pass, and burn-out heat flux limits for creep-feed grinding. The work begins with an analysis of fluid flow through the grinding zone. The model predicts tangential and radial fluid velocities relative to the wheel, the depth of fluid penetration into the wheel pores, and the useful flow rate through the grinding zone. The useful flow rates predicted using the model are combined with experimental measurements for both conventional and creep-feed wheels to estimate the effective wheel porosity, which provides a measure of the ability of a wheel to pump fluid through the grinding zone. Thermal models are then developed to predict the partition of the total grinding heat to the workpiece, the fluid, and the grinding wheel. The thermal properties of the composite depend on the effective wheel porosity as described above. Results are obtained for the local partition of the total energy to the workpiece and to the composite along the grinding zone for different grinding conditions. For creep-feed grinding in the absence of fluid burn-out, the energy partition to the workpiece is typically only a few percent of the total. Inverse heat transfer methods are developed to determine the heat flux distribution to the workpiece from measured temperature distributions for regular grinding of steels with both conventional aluminum oxide wheels and CBN wheels. These results are also used to estimate the energy partition to the workpiece, as well as the wheel-workpiece contact length and convective heat transfer coefficient on the workpiece surface. A transient thermal analysis was developed. For creep-feed grinding, the temperature rise is found to be much bigger than the quasi-steady state value at the end of the cut. The transient temperature model is subsequently applied to predicting burn-out heat flux limits for creep-feed grinding. (Abstract shortened by UMI.)
Mechanical engineering|Industrial engineering
Guo, Changsheng, "Investigation of fluid flow and heat transfer in grinding" (1993). Doctoral Dissertations Available from Proquest. AAI9408283.