Numerical Study of Laminar Confined Impinging Slot Jets with Nanofluids

Giuseppe Di Lorenzo,Oronzio Manca,Daniele Ricci,Sergio Nardini

doi:10.1155/2012/248795

Abstract

A solution to obtain efficient cooling systems is represented by the use of confined or unconfined impinging jets. Moreover, the possibility of improving the thermal performances of the working fluids can be taken into account and the introduction of nanoparticles in a base fluid can be considered. In this paper, a numerical investigation on confined impinging slot jet working with a mixture of water and Al2O3 nanoparticles is described. The flow is laminar and a uniform temperature is applied on the target surface. The single-phase model approach has been adopted. Different geometric ratios, particle volume concentrations, and Reynolds numbers have been considered in order to study the behaviour of the system in terms of average and local Nusselt number, convective heat transfer coefficient and required pumping power profiles, temperature fields, and stream function contours.

Highlights

Heat transfer enhancement is a significant issue in the research and industry fields
The dimensionless stream function contours showed that the vortex intensity and size depend on the confinement, Reynolds number, and particle concentration values
The introduction of nanoparticle produces an increase of fluid bulk temperature because of the elevated thermal conductivity of nanofluids

Summary

Introduction

Heat transfer enhancement is a significant issue in the research and industry fields. Both active and passive techniques can be employed. Impinging jets are applied to drying of textiles, film, and paper, cooling of gas turbine components and the outer wall of combustors, freezing of tissue in cryosurgery and manufacturing, material processing, and electronic cooling. Several studies have been developed on impinging air jets [1, 2] but liquid jets have been recently studied because they have possible application to the cooling of heat engines [5, 7], thermal control in electronic devices [8, 9], and the thermal treatment of metals and material processing [10,11,12]

Methods

Results

Conclusion