Investigation For Cooling Effect On Grinding Workpiece Surface Subjected To An Impinging Jet

Grinding is widely used in machining. But a grinding process generates a lot of heat, whichmakes the temperature of the grinding zone rise sharply and can cause various types of thermaldamage. So a grinding process generates heat that must be dissipated to avoid thermal damage.Impinging jets are known as a method of achieving high convective heat transfer coefficients. Onepotential applications of impinging jet heat transfer is the air jet cooling and the other is spraying jetcooling.They are both effective and environment-friendly. And have been effectively used in thegrinding process. Investigation was carried out to illustrate some of the flow and heat transfercharacteristics that occur when a single-air jet or spraying jet impinges on a flat plate with a rotatingdisk mounted above the surface, representative of the work-piece in a grinding process.The first objective aims to assess the detailed flow and heat transfer features in the vicinity of arotating wheel with air jet impinging by numerical and experimental investigation. Rotating speed, jetimpingement speed, distance, angle, and temperature are studied which may affect the flow and heattransfer characteristics. Simultaneously, the influence of swirl and entrainment effect yielded by therotating disk on jet impinging flow is studied through employing different kinds of coolant. Thesecond objective aims to accesses the quantitative evaluation for heat transfer enhancement on agrinding workpiece surface subjected to the spraying jet impinging by experimental investigation.Influence of rotating speed and water/air ratio is discussed.The results show that it is benefit for the air jet to cool the grinding zone when the jet impingingdirection is the same as the rotating direction of rotating disk. The action of swirl air around rotatingdisk can cool the surface of the workpiece and also discourage the jet air to get to the grinding zone.As the speed increases, the phenomenon is more obvious. While increasing the speed of the jet, the jetangle and lower jet temperatures are conducive to improving the convective heat transfer on thegrinding surface. But changing the distance is the less affected. The use of spraying jet cooling canimprove the cooling effect of the heated wall significantly. Especially at higher rotating speed, muchmore water droplet will get the cooling area. Furthermore, with the increasing of water droplet in thespraying jet, its cooling ability strengthens constantly.