The effect of Total flowrate on the cooling performance of swirling coaxial impinging jets

Abstract

Thermal management ability of swirling coaxial confined impinging air jets (SCCIAJ) are experimentally studied for different total flowrate. the coaxial structure of the jet is provided by a nozzle which is a cylindrical material having an inner round flow passage and three circumferential helical flow passages. Experiments are conducted for various values of dimensionless nozzle-to-plate distance (H / D = 0.5, 1.0, 1.5 and 2.0) and total flowrate (40, 50 and 60 LPM (liter per minute)). During the experiments, flowrate ratio (Q*) and heating power are set to constant values of 0.75 and 18.2 W, respectively. It is revealed that both the heat transfer rate and radial uniformity are improved by increasing total flowrate, while increasing spacing between the nozzle outlet and the target plate adversely affects the magnitude of Nusselt numbers. in this context, the condition of Q(tot) = 60 LPM with H / D = 0.5 presents the optimum case for heat transfer. the results obtained are also compared with the ones of the classical circular jet (Q* = 0) depending on the temperature distribution of the impingement surface. It is concluded that swirling coaxial jets with appreciate working conditions can be used as an effective tool for electronics cooling.