Abstract

Background: Liquid coolants are generally used for increasing the heat transfer rate of electronic devices. However, the fluids such as normal chemicals like water or ethylene glycol have very low thermal properties. A nanofluid is the mixture of suspended nanoparticles in the base fluid. It is recognized as an advanced heat transfer fluid that exhibits superior heat transfer properties. The aim of this paper is to investigating the hydrodynamic and thermal behavior of silver/water nanofluid flowing in a minichannel heat exchanger. The volume concentration of silver nanoparticle is changed between 0.25% to 0.5% and the Reynolds number value varying from 1000- 100000. A heat flux boundary condition with constant value of q=10000 W/m2 is applied in the test region.

Methods: Based on the literature review, a 2-D finite volume numerical method is used for finding the heat transfer coefficient of silver/water nanofluid in a mini-channel. The continuity, momentum, energy equations are discretized and non-dimensionalzed. Based on the boundary conditions, the problem is solved iteratively under steady state condition using SIMPLE algorithm.

Results: The thermal conductivity, dynamic viscosity and convective heat transfer coefficient (CHTC) of silver–water nanofluid is found for 0.5%, 0.35%, and 0.25% volume concentration of silver nanoparticles. The viscosity, thermal conductivity increases with increase in concentration of silver nanoparticle. The CHTC has the maximum increase in the laminar region at 0.5% concentration of silver nanipartical.

Conclusion: The results prove that there is an acceptable increase in heat transfer coefficient by 45.6% with just 0.5% volume concentration of the silver nanoparticles with respect to that of the base liquid.. Moreover, the increase in heat transfer coefficient is found to be approximately 12% in the laminar regime, and 20–25% in the transition regime when compared with that of the base fluid. For higher Reynolds number, Re>10000, percentage rise in heat transfer coefficient is found to be 30 to 35% in the turbulent regime.

Keywords: Laminar, nanofluids, numerical, silver nanoparticle, turbulent.

Graphical Abstract