An application of lubrication theory to grinding
- Univ. of Pittsburgh, PA (United States). Dept. of Mechanical Engineering
The objective is to calculate the maximum workpiece temperature. For this one must know the rate of cooling of the workpiece-wheel contact at given rate of energy input. In creep feed grinding cooling is principally by convection, less than 5% of the total heat is conducted away when the coolant is water. Convection, in its turn, depends on the rate of flow of the coolant through the grinding zone and on the rate at which heat is absorbed by the coolant. The authors model the grinding wheel as a porous disk, which owes its porosity to the bonded abrasive grit of irregular shapes and sizes. This wheel is rotated at high speed and is slid against a smooth plane surface, the workpiece. Fluid from a jet is supplied to cool the contact, which is a concentrated heat source. Portion of the coolant is forced into the pores of the wheel by a hydrodynamic pressure that develops ahead of the contact; this fluid absorbs some of the beat while being transported through the grinding zone by the revolving wheel. To solve for the flow rate across the grinding zone, the authors apply the thermohydrodynamic theory of lubrication, recognizing that the upstream pressure boundary condition is given by a rain effect. Heat transfer into the fluid that fills the pores is calculated by means of local volume averaging of the governing equations. With this application of lubrication theory, they obtain excellent agreement with experimental data for workpiece temperature distribution, including the maximum temperature, in both conventional and creep feed grinding, and for both water and oil coolants.
- OSTI ID:
- 163232
- Report Number(s):
- CONF-950116--; ISBN 0-7918-1297-9
- Country of Publication:
- United States
- Language:
- English
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