An Experimental Study on the Heat Transfer and Flow Characteristics of Aluminum Heating Elements Coated with Graphene

With the rapid development of clean heating, electric heating has received increasing attention. As a common electric heating device, heaters are also widely used in residential and industrial heating, as well as in other fields. In order to improve the reliability and heat transfer flow characteristics of the electric heating element of the heater, a new type of structural electric heating element was designed and developed based on the surface heat transfer enhancement and pit drag reduction characteristics of graphene. The heat transfer and flow characteristics of the electric heating element were analyzed through experiments, and the results showed that the average surface emissivity increases from 0.25 with the non-graphene-coated sample to 0.94 with the graphene-coated one, and the surface temperature of the electric heating element decreased from 289 °C to 237.5 °C. Through wind-tunnel experiments, it was found that the PEC value of the electric heating element with pits was 1.0693, and the Nusselt number increased by 6.22% compared with the smooth surface. Furthermore, after coating with graphene, the Nusselt number increased by 30.3% compared with the smooth surface.