Book Description
This research investigation examines the thermal behaviour of single and arrays of fluid jets impinging at heated surfaces, and formulates enhancement schemes for the jet impingement heat transfer processes for high-intensity cooling applications. The proposed techniques are numerically modelled and analysed over a wide parametric range to identify flow characteristics leading to thermal enhancement and optimum performance. The first scheme applies to a single fluid jet and incorporates a protruding object at the impingement surface to improve heat transfer. In this, a conical protrusion of high thermal conductivity is attached to the heated surface directly beneath the jet. Three different aspect ratios of 0.5, 1 and 2 are investigated for the protrusion while the inclusion of a fillet at the base of the cone is also studied. Jet Reynolds numbers between 100 and 30,000 are modelled. The observed thermal performance is compared with a reference case having no surface attachment. With this arrangement, the heat transfer rate typically varies between 10 and 40 percent above the reference case although depending on certain parametric combinations, the heat transfer may increase above or decrease below the reference performance. The highest indicated increase in heat transfer is about 90 percent while 15 percent below is the lowest. Careful selection of cone surface profile creates potential for further thermal enhancement.
