Nanofluid Implementation in Heat Exchanger Geometries

Abstract

In recent years, nanotechnology has evolved as an important field that employs sophisticated "green" nanoparticles incorporated in conventional engineering resources. The heat transfer performance of nanofluids is superior to that of traditional heat transfer fluids. Suspending nanoparticles in nanofluids increases the ratio of contact surface to volume. Consequently, they can be placed evenly to maximize heat transfer without incurring a significant decrease in pressure. In the cooling and heating sectors, nanofluids are a preferred heat transfer fluid due to these benefits. The considerable increase in heat conductivity that nanoparticles provide has made nanofluids highly desirable for a variety of energy applications. In the past decade, thermal effects of nanofluids in both forced and free convection flows have been of great interest to researchers. In our current study, we investigated the influence of nanofluid coolants in spherical dimpled surfaces on heat transfer and pressure drop. The primary purpose of this research is to assess the thermal performance of nanofluids with regard to varying Reynolds numbers and nanoparticle volume concentrations in a dimpled channel flow. Assuming a constant and uniform heat flux of 10000 w/m2, the simulations are performed at Reynolds numbers from 10000 to 30000. The computational fluid dynamics solver ANSYS Fluent is used to analyze the effective properties of nanofluids based on models presented in the literature. There is a discussion on the results of heat transfer coefficient, temperature distributions, Nusselt number, pressure drop, and friction factors for all the scenarios. Different nanoparticle compositions were shown to have a 20-25% higher heat transfer coefficient for dimpled channels compared to smooth ones. With increasing volume fractions, it was found that heat transfer and pressure drop values did go up. Nusselt number grows as more complex corrugations are being used. Because the performance evaluation factor (PEF) for corrugated geometries is greater than unity, they can surpass smooth pipes. In addition to the decrease in PEF values, both Re and PEF advances show a decreasing trend as well.