Study On The Effect Of Three Dimensional Graphene Nanofluid On The Cooling Performance Of Automobile Radiator

Nowadays energy efficient utilization have always been an important topic.The development of new nanotechnology and graphene industry provides strong support for the preparation and development of new coolant.Compared with the traditional coolent,graphene nanoparticles coolent has better heat transfer performance.This new coolant provides a new way to improve engine cooling performance.In this paper,the convective heat transfer performance of graphene nanoparticle solution in engine radiator is studied by experiments and simulations.First,four different mass fractions(0.1 wt%,0.2wt%,0.3wt%,0.4wt%)of graphene nanoparticle coolant were prepared using a 50%ethylene glycol aqueous solution as the base fluid.Then,a test bench consisting of a fan,an engine radiator,a heating circulation device,a temperature and pressure sensor,a flow meter,etc.is designed and built,and different inlet temperatures,flow rates,particle mass fractions,and air flows of the radiator are tested and measured on the gantry.Wait for the exit temperature and pressure and the wall temperature of the radiator.Finally,the three-dimensional fluid simulation software was used to simulate the outlet temperature of the radiator and the pressure drop at the inlet and outlet,which verified the rationality and accuracy of the experiment.The main conclusions are as follows:(1)Increasing the flow rate of the graphene nanoparticle coolant can enhance heat transfer.At an inlet temperature of 85?,the convective heat transfer coefficient of the 0.1 wt%nanoparticle solution at the flow rate of 1.2m3/hincreased by 14.3%compared to 0.6m3/h.(2)Increasing the inlet temperature of the graphene nanoparticle coolant can enhance heat transfer.At a flow rate of 1.2m3/h,the convective heat transfer coefficient of the 0.1 wt%nanoparticle solution at 85? and 75? increased by 24%and 13%,respectively,relative to the base fluid.(3)Increasing the mass fraction of graphene nanoparticles can significantly increase the convective heat transfer coefficient of the solution.At an inlet temperature of 80?,the convective heat transfer coefficient of the 0.1 wt%nanoparticle solution at 1.2m3/h increased by 17%compared to the base fluid.the convective heat transfer coefficient of 0.4wt%nanoparticle solution compared to 0.1 wt%nanoparticle solution only increased by 15%.(4)The fan can drive the air near the radiator to conduct forced convection,increase the convection heat transfer,and increase the convective heat transfer coefficient of the coolant.At an inlet temperature of 85 °C and a flow rate of 1.2 m3/h,the convective heat transfer coefficient of the 0.1 wt%nanoparticle solution was 40.8%higher when the fan speed was 1200 r/min compared to no wind.(5)Adding graphene nano-particles can increase the viscosity of the cooling liquid,thereby increasing the flow resistance of the cooling liquid,weakening the convective heat transfer intensity of the coolent,and resulting in a decrease of the convective heat transfer coefficient.The experimental data show that the addition of graphene nanoparticles can significantly increase the convective heat transfer coefficient of the coolant.This shows that the addition of graphite dilute nanoparticles has a positive effect on increasing the convective heat transfer coefficient of the coolant far more than the negative effect.