Machining with minimum quantity lubrication (MQL) or minimum quantity cooling (MQC) as a subset of green machining is a process in which small volume fluid of high lubrication and cooling properties alongside high pressure air is used in the material removal process. The heat generated in the grinding process has a great impact upon the workpiece quality. Serving lubrication and heat transfer functions, cutting fluids have an essential role in reducing the temperature and thus improving the process of grinding. In this research, nanofluid made of graphene nanoparticles in water-based fluid as a cutting fluid of high heat transfer is utilized to investigate the effects of nozzle number and nozzle geometry of the MQC system on the cutting temperature and surface roughness of the workpiece. The effect of geometry and number of nozzles on grinding with MQC has not been studied so far. The study findings show that the nozzle outlet cross-section of rectangular, compared to circular, decreases the surface roughness and temperature by 30% and 36%, respectively. Moreover, compared to the single nozzle, the use of three nozzles results in a decrease of 19% and 31.7% in the surface roughness and temperature. Under the same machining conditions, the MQC method by 0.15wt.% nanofluid of graphene in water using a rectangular nozzle outlet of 1.2mm width makes surface roughness and temperature reduced by 67.2% and 48.3% compared to the dry condition, whereas decreased by 13.4% and 8.8% compared to the wet method, respectively.

中文翻译：

---

喷嘴数量和出口几何形状对纳米流体微量冷却 (MQC) 磨削过程的影响

微量润滑 (MQL) 或微量冷却 (MQC) 作为绿色加工的子集的加工是在材料去除过程中使用具有高润滑和冷却性能的小体积流体以及高压空气的过程。磨削过程中产生的热量对工件质量有很大影响。切削液具有润滑和传热功能，在降低温度从而改善磨削过程中起着至关重要的作用。本研究利用石墨烯纳米粒子在水基流体中制成的纳米流体作为高传热切削液，研究MQC系统的喷嘴数量和喷嘴几何形状对工件切削温度和表面粗糙度的影响。到目前为止，尚未研究几何形状和喷嘴数量对 MQC 研磨的影响。研究结果表明，与圆形相比，矩形喷嘴出口截面的表面粗糙度和温度分别降低了 30% 和 36%。而且，与单喷嘴相比，使用三个喷嘴导致表面粗糙度和温度分别降低了19%和31.7%。在相同的加工条件下，MQC方法提高了0.15使用 1.2 的矩形喷嘴出口 wt.% 石墨烯在水中的纳米流体mm宽度使表面粗糙度和温度与干法相比降低了67.2%和48.3%，而与湿法相比分别降低了13.4%和8.8%。