دانلود رایگان مقاله انگلیسی جریان سیال و انتقال حرارت نانوسیال ها در جاذب حرارت میکروکانال با چیدمان ورودی و خروجی - الزویر 2017

Abstract

The fluid flow and heat transfer characteristics of laminar nanofluid flow in microchannel heat sink (MCHS) with V-Type inlet/outlet arrangement are numerically studied. A constant heat flux boundary condition is applied on the base plate of MCHS and all the other surfaces of MCHS are insulated. Four different kinds of nanofluids are utilized as working fluids which are SiO2, Al2O3, ZnO and CuO dispersed in pure water as a base fluid. Three different volume fractions of 1%, 1.5% and 2% and three distinctive nanoparticle diameters of 30 nm, 40 nm and 60 nm were employed. The results specify that the SiO2 nanofluid has the uppermost heat transfer rate compared to other tested nanofluids. Increasing the nanoparticles volume fraction together with decreasing the nanoparticles diameter enhances the Nusselt number value. The pressure drop coefficient did not change significantly by using nanofluid with various volume fractions and varied nanoparticle diameters. Moreover, the results indicate that nanofluid can enhance the performance of MCHS with V-shaped inlet/outlet arrangement.

4. Conclusions

A numerical simulation of laminar forced convection heat transfer in MCHS with V-Type inlet/outlet arrangement was performed. The current study focused on flow field and heat transfer improvement caused by different parameters, such as different kinds of nanofluids including SiO2, Al2O3, ZnO and CuO, different volume fractions of nanoparticles (0, 1, 1.5 and 2%) and different nanoparticle diameters (30, 40 and 60 nm). FVM was used to solve and discretize the governing equations. It was found that SiO2, Al2O3, ZnO and CuO nanofluids in water base fluid had better heat transfer augmentation compared to pure water. The results show that SiO2 nanofluid presents the maximum Nusselt number value among tested nanofluids and pure water. The increase of nanoparticle volume fraction enhanced the average Nusselt number. Moreover, the Nusselt number had a small enhancement with decreasing the nanoparticle diameter. Besides, the flow fluid shows that SiO2 nanofluid had the uppermost pressure drop among tested nanofluids and pure water. Following this, the larger volume fraction and smaller nanoparticle size increase the pressure drop. No considerable effect was detected on the pressure drop coefficient in the case of using nanofluid in comparison with pure water. SiO2 nanofluid with volume fraction of 2% and nanoparticle diameter of 30 nm had the best performance among other tested nanofluids.