CFD analysis and environmental assessment on the heat transfer and flow of the pure water or water/silver Nano fluid coolants in a plate-fin heat sink applying two-phase mixture model

Abstract

Environmental impacts are the consequences caused by the elementary flows on human health, plants, and animals (ecological health) or by the future availability of natural resources (resource depletion). The heat transfer characteristics of a plate-fin heatsink were investigated using a 3-dimensional numerical analysis based on the two-phase mixture model. The effect of using NF, fin spacing, and fin height on the performance of the system were studied considering the constant heat flux of 100 kW/m2 at the bottom of heatsink and NF inlet temperature of 300 K. The results showed that the increase in the secondary fin height (hsf) from 5 mm to 17.5 mm leads to increase in the pressure drop by 11.6%, 52%, to improve the heat convection coefficient (h) by 32.92%-23.84%, and consequently reduces the central processing unit (CPU) mean temperature by 4.31% and 2.34% for Re=500-2000. The maximum performance evaluation criterion (PEC) was obtained as 1.11-1.05 at Re numbers of 500-2000 for heatsink with hsf=12.5 mm. In addition, the optimum location for the secondary fin was determined to be at the mid-space of two primary fins (dsf=0.5 mm) which leads to improving h by 18%-5% at Re numbers of 500-2000 as compared to other fin spacing scenarios. Moreover, the intensification of nanoparticle concentration (ψ) leads to improve h by 15.71%-17.21% for Re=500-2000. Besides, the escalation of ψ decreases the pressure drop by 14.18% for all Re numbers. The PEC of the system with hsf=12.5 mm, ψ=1%, at Re=2000 was obtained as the highest PEC of 1.226 among the other studied cases. According to the design, the heat sink has an environmental impact of 0.5233.