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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 0.15 wt.% nanofluid of graphene in water using a rectangular nozzle outlet of 1.2 mm 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. [ABSTRACT FROM AUTHOR]