Modeling for prediction of tool-chip interface temperature in internal cryogenic turning considering film boiling

The cutting temperature model is critical for studying surface quality and tool wear. Cutting temperature models have been widely studied. When liquid nitrogen is used as a cooling medium in machining, the liquid nitrogen will inevitably appear Leidenfrost effect and film boiling will occur. However, the effect of film boiling on the cutting temperature is rarely concerned in the former temperature model. In this research, a novel model for tool-chip interface temperature considering film boiling is proposed. The new proposed model fully considered the thickness of the gas layer caused by the Leidenfrost effect compared with current models including Kesriklioglu's model and Rozzi's model. Based on the model, the effects of different gas layer thickness on the gas layer temperature and the tool-chip interface temperature were analyzed. The results indicate that thickness of the gas layer has a significant effect on the heat transfer properties and the tool-chip interface temperature of liquid nitrogen during the cooling process. The effect of film boiling must be considered in the temperature modeling of liquid nitrogen cooling machining. The new proposed model was accurately validated with a maximum error of less than 20% compared to previous studies and cutting experiments. It is also demonstrated that the developed liquid nitrogen internal cooling turning tool can control the gas layer thickness to about 5 mu. This study reveals the heat transfer mechanism of cryogenic cooling, which helps to improve the cooling efficiency and the reliability of cryogenic cooling processing in industrial applications.