The interaction between two radial jets

Abstract

Arrays of impinging jets are used in industry for heat and mass transfer processes. A new type of jet was recently developed which could be utilized in such arrays. This jet is the radial jet and it offers the advantages of variable net force on an impingement surface with high surface heat and mass transfer. The objective of this study was to characterize the flow, surface pressure, and heat transfer for two radial jets as a function of nozzle geometry, in order to be able to design arrays of radial jets. Two negative force radial jet reattachment (RJR) nozzles were designed with -10 deg exits. Also a support structure that permitted adjustable nozzle spacing was designed. A flow visualization facility was used to identify four major flow types as a function of RJR nozzle spacing. Each of the four flow types corresponded to a unique surface pressure coefficient distribution and local convection coefficient distribution. The local heat transfer results were used to determine the average heat transfer as a function of impingement area. Nusselt number and Stanton number correlations were developed for the impingement surface. The correlations were functions of Reynolds number, nozzle geometry, and flow type. These correlations may be used to estimate the surface heat transfer with a RJR nozzle array with -10 deg exits.