A Model of the Fluid Convective Cooling in Grinding Process

Abstract

The grinding process has particular interest in that contact temperatures have great significance for quality and integrity of machined surfaces. Hardened surfaces may be damaged by softening and or being stressed, being hardened or re-hardened, burned or cracked. It is important in grinding for the fluid to remove heat from the grinding contact zone to avoid thermal damage to the workpiece surface and/or sub-surface layers. The cooling effect of grinding fluid can be quantified by the convective heat transfer coefficient (CHTC) acting in the grinding zone. This paper presents values of the CHTC based on measured grinding temperatures. The paper also presents a new convective heat transfer model based on principles of applied fluid dynamics and heat transfer. Predicted values for the CHTC calculated from the model are compared with results from experiment obtained under a range of grinding conditions and with experimental data. The results demonstrate that the new CHTC model improves the accuracy of prediction and helps explain the variation in the value of CHTC under varying process conditions. Results also show that convection efficiency strongly depends on the grinding wheel speed, grinding arc length and fluid properties.