The traditional flood cooling method applied in the internal turning process has disadvantages, such as having a low cooling efficiency and being environmentally unfriendly. In the present work, an internal spray cooling turning tool was designed, and the performance was numerically and experimentally accessed. The heat transfer simulation model of the internal spray cooling turning tool was established by ANSYS Fluent, and the tool cooling structure parameters were optimized by the Taguchi method based on the CFD simulations, and obtains the diameters of the upper and lower nozzles of 3 mm and 1.5 mm, respectively; the distance between the upper nozzle and the tool tip of 18.5 mm. To evaluate the cutting and cooling performance of the optimized tool, internal turning experiments were conducted on QT500-7 workpieces. Results show that the optimized tool with internal spray cooling led to lower workpiece surface roughness and chip curling, compared to the conventional tools.

Aiming at the demand of high efficiency green cooling cutting of difficult-to-machine materials, a novel composite cooling turning tool design concept based on circulating internal cooling combined with spray cooling is proposed in this paper. Thermal-fluid-solid coupling simulation models were developed based on FLUENT software, which are applied to investigate the cooling performance of two type of composite cooling tool which are single-nozzle type and double-nozzle type, and the circulating internal cooling tool. Simulations results shown that the tool-chip interface temperatures of the three tools are from low to high under the same conditions, followed by the composite cooling turning tool with double-nozzle, the composite cooling tool with single-nozzle and the circulating internal cooling tool. The double-nozzle type of the composite cooling tool exhibits a better cooling and lubrication performance.