热管砂轮通过将环形热管与磨削工具砂轮相结合,利用环形热管的高导热性,达到降低磨削弧区温度,避免工件烧伤的目的.虽然已开展的研究已经充分验证了热管砂轮应用于难加工材料高效磨削时强化弧区换热的可行性,但对其换热机理和具体换热性能还有待更深层次的研究.通过对热管砂轮的换热性能开展试验研究,探究相关因素(砂轮转速、磨削弧区热流密度、充液率和冷端条件)对热管砂轮换热性能的影响,优化出热管砂轮的使用参数.

In order to figure out the burnout problem during grinding process, a novel method about enhancing heat transferring in the contact zone by incorporating a revolving heat pipe inside the wheel disk has been proposed. By designing the structure and analyzing the heat transfer process of heat pipe grinding wheel (HPGW), factors as working fluid kind, fluid loading and rotating speed are determined to be the main factors that may affect its heat transfer capacity. Heat transfer analysis experiments were complemented on a self-designed experiment platform, on which the influences of different factors are investigated. According to the results of the heat transfer analysis experiments, a CBN HPGW injected with 18 g distilled water is fabricated and applied in creep feed grinding of Inconel 718. The results are compared with non-HPGW in terms of the average temperature in the contact zone, workpiece surface quality, microstructure and micro-hardness of the ground workpiece surface and the grinding wheel surface. Results show that the temperature in the contact zone can be controlled below 60℃ when using HPGW, while sever burnout happened when using non-HPGW at the same conditions, which confirmed the excellent heat transfer performance of HPGW.

A vertical rotating heat pipe was incorporated in the abrasive-milling tool to help dissipate heat during the machining process and realize green machining of difficult-to-machine materials. In this study, a simulation is performed to investigate the heat transfer mechanism in the evaporator and condenser section of the rotating heat pipe abrasive-milling tool (RHPAMT) at a rotational speed of 1600 rpm. The results indicate that natural convection boiling heat transfer occurs in the evaporator. Film condensation is the heat transfer regime in the condenser section. The heat transfer performance of the RHPAMT is investigated in dry abrasive-milling of Ti-6Al-4V with different cooling conditions, filling ratio and feed speed. Dry machining without rotating heat pipe is also performed and compared with RHPAMT. The optimal heat transfer performance can be obtained with a cooling pressure of 0.36 MPa and a filling ratio of 16.4%. The temperature in the evaporator section can be lowered by approximately 65.7% compared to the same machining process without heat pipe. (C) 2016 Elsevier Ltd. All rights reserved.

Defects caused by high grinding temperatures on both workpieces and grinding wheels become more significant with the development of difficult-to-machine materials and creep-feed grinding procedures. The coolants normally used to dissipate heat can cause harm to the environment as well as increase machining costs. A novel idea that incorporates a revolving heat pipe into the grinding wheel has been proposed to enhance heat transfer in the contact zone. In this study, a simulation is performed to investigate the heat transfer mechanism in the evaporator and condenser section of a revolving heat pipe grinding wheel (RHPGW) at a wheel velocity of 45 m/s. The results indicate that natural convection heat transfer and film condensation occur under this condition. The heat transfer and startup performance of the RHPGW are investigated in further experiments with different working fluids, fluid loadings and rotational speeds. Finally, experiments on creep-feed grinding of Inconel 718 are performed using a RHPGW and a grinding wheel without a revolving heat pipe, without application of any coolant. The results show that grinding temperatures can be maintained below 100 degrees C with a RHPGW and both the workpiece and grinding wheel show better quality than those when grinding is performed without a revolving heat pipe. (C) 2016 Elsevier Ltd. All rights reserved.