Thermal performance of a radial-rotating oscillating heat pipe and its application in grinding processes with enhanced heat transfer

Grinding difficult-to-machining materials can generate massive heat. The heat generated by grinding easily accumulates in the grinding zone (the contact area between workpiece and wheel), leading to high temperatures, which harms the grinding quality and efficiency. Radial-rotating oscillating heat pipe (RR-OHP) can achieve high thermal performance and can potentially to apply in grinding with enhanced heat transfer. The RR-OHP is supposed to be designed in the grinding wheel to improve the heat transport ability, in this case, grinding heat can transfer out directly via the grinding wheel. RR-OHP needs to obtain high thermal performance under radial rotations, while the related research is still insufficient. In this paper, the influence of centrifugal acceleration (0 – 1620 m/s2), working fluid properties (methanol, DI water), and heat flux (1.5 × 104 – 4 × 104 W/m2) on the heat transport capacity are studied. A prototype of a grinding wheel combined with RR-OHPs is developed. A grinding simulation by the wheel is built to demonstrate the enhanced heat transfer of RR-OHPs in grinding process. Results show that the increment of heat flux and centrifugal acceleration can improve the thermal performance of RR-OHPs. The thermal resistance of RR-OHP filled with methanol is smaller than that of RR-OHP filled with DI water. In addition, under the condition that grinding speed of 12 m/s, infeed speed of 360 mm/min, and 1 mm depth of cut, the grinding wheel embedded with 16 RR-OHPs can transfer out 79% of total heat and control the temperature under 262 °C, based on the grinding simulation. On the contrary, the grinding wheel without RR-OHPs transfers only 34% of the total grinding heat, and the temperature reaches up to 766 °C.