A study on thermal performance of revolving heat pipe grinding wheel

• Published in: Applied thermal engineering 2021-01, Vol.182, p.116065, Article 116065
• Main Authors: Chen, Jiajia, Fu, Yucan, Qian, Ning, Ching, Chan Y., Ewing, Dan, He, Qingshan
• Format: Article
• Language: English
• Subjects: Acceleration; Coolants; Cooling; Cooling effects; Crystal defects; Environmental effects; Evaporation; Evaporators; Film boiling; Film condensation; Grain refinement; Grinding; Grinding wheels; Heat flux; Heat pipes; Heat transfer coefficients; Heat transfer performance; High temperature; Laminar heat transfer; Natural convection; Nucleate boiling; Pipes; Plastic deformation; Revolving heat pipe; Studies; Two phase flow; Workpieces
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2020.116065

•Boiling is superseded by laminar convection as increasing the rotational speed.•Film condensation is the heat transfer mechanism in the condenser.•Suitable heat flux from 2500 to 50,000 W/m2 and filling ratio of 17% was found.•Revolving heat pipe shows better cooling effect than coolants in grinding process. The heat generated in the grinding process can result in high temperatures in the grinding contact zone, and result in defects to both the workpiece and the grinding wheel. Typically, coolants are used to transfer heat from the contact zone. This process, however, is not satisfactory as coolants often lose efficacy due to film boiling and can result in adverse health and environment effects. A novel cooling method that incorporates a two phase revolving heat pipe within the annular disk of the grinding wheel has been proposed. In this paper, the heat transfer mechanism in the evaporator section and the condenser section was analyzed using the volume of the fluid (VOF) model in ANSYS/FLUENT. The influence of different evaporator geometry, input heat flux, filling ratio and rotational speed on the heat transfer performance are reported here. In the evaporator, nucleate boiling is suppressed and replaced by laminar convection heat transfer as the rotational acceleration exceeds 1033g. The ideal filling ratio is about 17% with a corresponding heat transfer coefficient of 6091 W/(m2·K) and the appropriate heat flux is in the range 2500 to 500,000 W/m2. Grinding experiments with both revolving heat pipe cooling and coolant cooling are performed, and the results analyzed in terms of grinding temperature and workpiece quality. The average grinding temperature was found to be under 120 °C with revolving heat pipe cooling, while temperature spikes as high as 800 °C with severe plastic deformation and grain refinement beneath the workpiece surface was found with coolant cooling.