CONJUGATE HEAT TRANSFER FROM A FLAT PLATE WITH SHOWER HEAD IMPINGING JETS

Conjugate heat transfer from a flat circular disk is investigated both computationally and experimentally with a constant heat flux imposed on its bottom surface and a shower head of air jets impinging on the top surface. The shower head consists of a central jet surrounded by four neighboring perimeter jets. Measured temperature data at twelve locations within the plate are compared with the conjugate heat transfer result obtained at the same locations computationally by Shear Stress Transport (SST) - turbulence model. The spacing to orifice diameter ratio (H/d = 1 to 4), the jet Reynolds number (7115 to 10674) and the plate thickness to diameter ratio (0.25, 1 and 2) are varied. Measured temperature data within the solid plate agrees well with the computationally obtained conjugate heat transfer result. Primary peaks of the Nusselt number at the stagnation point and secondary peaks at the interaction points of the wall jets are observed. Local variation of heat transfer rate with varying H/d is significant but found to be less sensitive to the thickness ratio. When compared with a single jet of equal mass flow rate and Reynolds number, the shower head jets provide more uniform temperature distribution with higher heat transfer rate.