HEAT TRANSFER ENHANCEMENT INVESTIGATION IN JET IMPINGEMENT SYSTEM OF A SINGLE AND ARRAY OF SQUARE JETS USING NUMERICAL TOOLS

Abstract

Computational fluid dynamics (CFD) techniques can predict complex fluid flow structures and the thermal performance of jet impingement systems. Numerical studies can complement extensive and time-consuming experimental studies where local parameter measurements are difficult and costly to obtain. In the current work, a combination of one, four, and nine square jets impingements are numerically investigated with CFD for mass flow rate (m) ranging from 2.71 &times; 10^-4 to 7.40 &times; 10^-4 kg/s. The effects of the jet's outlet-to-target plate distance (<i>Z</i>) are assessed as a function of the width of a single square nozzle (<i>B</i>). The flow field features of different nozzle configurations are also studied. It is shown that the Nusselt number increases as the mass flow rate increases, but increases inversely as the dimensionless jet's outlet-to-target plate spacing <i>Z/B</i> increases. The numerical investigation also demonstrates that when increasing the number of nozzles under a constant mass flow rate, the Nusselt number significantly increases. The effect of nozzle configuration is not that significant at <i>Z/B</i> &#62; 7. It is found that the present impinging jet system offers about 63&#37; enhancement in thermal efficiency, while the pumping power increases by 3.7 times. All simulations are successfully validated with experimental data.