%0 Journal Article
%T Numerical Study of Laminar Confined Impinging Slot Jets with Nanofluids
%A Giuseppe Di Lorenzo
%A Oronzio Manca
%A Sergio Nardini
%A Daniele Ricci
%J Advances in Mechanical Engineering
%D 2012
%I SAGE Publications
%R 10.1155/2012/248795
%X 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. 1. Introduction Heat transfer enhancement is a significant issue in the research and industry fields. Both active and passive techniques can be employed. The impinging jets are classified into the category of the active methods, and they have been widely used in several industrial applications as a means of providing high localized heat transfer coefficients. In fact, 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. There are numerous papers concerning this problem, and the analyses have been performed both numerically and experimentally [1¨C6]. 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¨C12]. The main configurations include circular or slot jets, and their flow and heat transfer mechanics are significantly different. It seems that more research activity on heat and mass transfer with circular impinging jets has been predominantly published [1¨C3, 13, 14]. However, investigations on heat and mass transfer with slot jet impingement have attracted more attention recently. In fact, slot jet impingements offer some benefits in cooling effectiveness, uniformity, and controllability, as underlined in [15]. These features are suitable with ones required by the modern electronic packages, characterized by increasing heat flux and decreasing dimensions [15¨C21].
%U http://www.hindawi.com/journals/ame/2012/248795/