Abstract
In the present study, we report the results of the experiments conducted on the convective heat transfer of graphene nano-platelets dispersed in water-ethylene glycol. The graphene nano-suspension was employed as a coolant inside a micro-channel and heat-transfer coefficient (HTC) and pressure drop (PD) values of the system were reported at different operating conditions. The results demonstrated that the use of graphene nano-platelets can potentially augment the thermal conductivity of the working fluid by 32.1% (at wt. % = 0.3 at 60 °C). Likewise, GNP nano-suspension promoted the Brownian motion and thermophoresis effect, such that for the tests conducted within the mass fractions of 0.1%–0.3%, the HTC of the system was improved. However, a trade-off was identified between the PD value and the HTC. By assessing the thermal performance evaluation criteria (TPEC) of the system, it was identified that the thermal performance of the system increased by 21% despite a 12.1% augmentation in the PD value. Furthermore, with an increment in the fluid flow and heat-flux applied to the micro-channel, the HTC was augmented, showing the potential of the nano-suspension to be utilized in high heat-flux thermal applications.
Highlights
With the advancement in the thermal process engineering, efficient cooling technologies with the capability to dispossess heat from high heat-flux areas are highly demanded, and this is the main driver for developing various types of heat exchangers for different cooling applications [1,2].Heat exchangers have a vital role in chemical and mechanical processes by providing an opportunity to exchange a large amount of heat between a heat source and a cold fluid within a confined space [3,4].Depending on the application of the heat exchanger, available space, and the type of the heat transfer fluid, various configurations of the heat exchangers have been designed
To evaluate the potential influence of the chemical synthesis on the physical properties, and the thermal performance of the systems, Sarafraz et al [17] performed several experiments to evaluate the pumping power, thermal performance, and the fluid behavior of a biologically-produced nanofluid inside a micro-channel heat exchanging block. They assessed the system in laminar heat and fluid-flow and noticed that the presence of the synthesized silver nanoparticles can improve the performance of the system, while adding small increments to the pressure drop (PD) value
At can be concluded that the thermal performance of the system enhances with the Reynolds number augmentation, such that the largest thermal performance evaluation criteria (TPEC) is recorded for the enhances with
Summary
With the advancement in the thermal process engineering, efficient cooling technologies with the capability to dispossess heat from high heat-flux areas are highly demanded, and this is the main driver for developing various types of heat exchangers for different cooling applications [1,2]. Manay et al [21] studied the potential impact of the micro-channel height and the volumetric concentration of titanium oxide nanoparticles on the thermal performance and fluid-flow specifications of the nanofluid They found that the convection heat transfer mechanism was promoted, while a small increase in the PD value was registered, which slightly augmented the pumping power. To evaluate the potential influence of the chemical synthesis on the physical properties, and the thermal performance of the systems, Sarafraz et al [17] performed several experiments to evaluate the pumping power, thermal performance, and the fluid behavior of a biologically-produced nanofluid inside a micro-channel heat exchanging block They assessed the system in laminar heat and fluid-flow and noticed that the presence of the synthesized silver nanoparticles can improve the performance of the system, while adding small increments to the PD value.
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