Effect of nozzle geometry on pressure drop and heat transfer in submerged jet arrays

Abstract

In the area of concentrating photovoltaics, where replacing expensive solar cell area by less expensive concentrator material is used as a way of reducing costs, one of the principal concerns is excessive heating of the photovoltaic cells. If the cells are not cooled efficiently, an elevated cell temperature can dramatically reduce their efficiency and can also lead to irreversible cell damage. In addition, there is a need for a cooling system which delivers a high rate of cooling at a minimum pumping power requirement. Liquid jet impingement is a promising method for this purpose because of its potential for very high heat transfer coefficients [1]. This technology is widely used in areas such as the thermal treatment of metals, cooling of internal combustion engines and thermal control of high power density electronic devices [2]. Various aspects of jet impingement such as the effect of Reynolds number, Prandtl number, nozzle-to-plate spacing, nozzle pitch and nozzle geometry have been studied extensively. Comprehensive literature reviews on jet impingement in generalare given by Martin [3], Webb and Ma [2] and Han and Goldstein [4]. This technical note deals specifically with the effect of nozzle configuration in submerged, confined jet arrays. Several other studies have investigated the effect of nozzle geometry on the Nusselt number of impinging jets. Lee and Lee [5] compared the heat transfer characteristics of