Effect of Interference of Impinging Round Jets on the Cooling Intensity of Heat Transfer Surfaces

Abstract

Impinging round parallel jets are one of the simplest and most efficient tools of heat and mass transfer enhancement and they are applied in cooling electronic equipment, gas turbine blades, combustion chamber walls, etc. As a rule, these devices use a system of jets. One of the simple ways to study the interaction of a jet array is to study the interaction between two jets. However, even with this approach, there are a large number of parameters that affect the process of jet interaction: the distance between the jets, the ratio of diameters, the ratio of flow rates, etc., and this greatly complicates the description of characteristics of the interaction of turbulent jets with each other and with the surface. Moreover, in a jet array, each jet is surrounded by at least two jets, so in this work we investigated heat transfer of two- and three-jet cooling and looked for differences between them. In the experiments, the distances between the jets and from the nozzle to the surface were varied. Local heat transfer characteristics were analyzed using infrared thermography. It was found that at distance s/D \(=\) 1.2, the distribution of local Nu for the three-jet interaction differs significantly from the two-jet interaction, however, at s/D \(=\) 1.8, there are almost no visible distinguishing characters.