Abstract
Owing to the rapid development of a number of technological and industrial sectors, high-performance electronic devices are now ubiquitous in modern engineering and industrial applications. Effective heat management is crucial to the smooth operation of such devices, and sometimes conventional methods of heat transfer fail to deliver the required performance. Recent advances in the field of nanofluids are a promising route to improve heat-transfer performance, and this is our motivation. We propose two computational fluid dynamics models for a rotor-stator cavity operating at Reω = 1.0 × 105 and filled with a fluid that consists of different volume fractions of Al2O3 nanoparticles. The first model simulates the nanofluid mixture using a single-phase transport model, and the second approach uses a two-phase transport model that allows for the relative velocity between the particle and fluid phases. All simulations are conducted using the second-order accurate solver, OpenFOAM®, that is based on the finite volume method and using Large eddy simulation methods. Our results show that the higher volume fractions of Al2O3 nanoparticles can achieve higher heat transfer rates, and at the same time, dilute nanoparticle concentrations have subtle effects on the momentum transport of the system. This is an advantage over micro-particle dispersion. Furthermore, we consider the effects of particle forces in the two-phase model, such as Brownian and thermophoresis forces, and suggest that the thermophoresis forces are the dominant effect within the cavity geometry.
Highlights
The non-isothermal fluid flow over a rotating disk has been investigated thoroughly in the previous literature.1–5 As a result, we know that the induced fluid motion due to the disk’s surface rotation is a critical driving force of the heat transfer properties of the resulting boundary-layer flow
We propose two computational fluid dynamics models for a rotor-stator cavity operating at Reω = 1.0 × 105 and filled with a fluid that consists of different volume fractions of Al2O3 nanoparticles
This study considered the development of two computational models to evaluate rotor-stator cavities filled with nanofluids
Summary
The non-isothermal fluid flow over a rotating disk has been investigated thoroughly in the previous literature. As a result, we know that the induced fluid motion due to the disk’s surface rotation is a critical driving force of the heat transfer properties of the resulting boundary-layer flow. Mushtaq and Mustafa studied a nanofluid flow over a stretching rotating disk with an axial magnetic field using the Buongirno model for the Brownian diffusion and thermophoresis forces These prior investigations on rotating disk boundary layers are based on the theoretical solutions of the von Karman similarity velocity profiles which, while accurate, require underlying assumptions that are too restrictive compared to full-fledged numerical methods. The flow fields are assumed to be fully laminar, and no indication of the turbulent behavior of the flow has been given, nor has consideration been given to particle diffusion due to Brownian and thermophoresis effects In this current study, we propose finite volume method (FVM)-based LES computational models for the rotor-stator flow. The local and the mean Nusselt number distributions will be presented to show the quantitative increases in the heat transfer performance of the rotor-stator cavities filled with Al2O3 based nanofluid
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