Conjugate Heat Transfer From a Flat Plate With Shower Head Impinging Jets

Abstract

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) κ-ω 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.

Effect of surface thickness on the wetting front velocity during jet impingement surface cooling

“…Nevertheless, even if the conjugate heat transfer is taken into account, there is some temperature gradient that exist between bottom and the top of the hot surface. The amount of temperature gradient will be larger for thick surface as compared to the thin surface [29]. Hence, the quenching of thin surface is much faster than the thick surface or the surface of 1 mm thickness attains the rewetting state much earlier than the surface of 3 mm thickness.…”

“…For a certain coolant flow rate and coolant temperature, the amount of energy available to be removed with thicker surface is larger as compared to the energy available with thinner surface. Several investigators have analytically evaluated the process of jet impingement surface quenching by considering the effect of conjugate heat transfer under transient and steady state condition [28][29][30]. The heat transfer characteristics of convective boundary layer flow over a flat plate are very much affected by the type of the thermal boundary conditions imposed at the top of the surface, which, is in contact with the fluid.…”

Development of a low thermal resistance water jet cooled heat sink for thermoelectric refrigerators

“…Behnia et al [13] reported that in the case of a single jet impingement, confined and free-surface jets provide nearly similar heat transfer coefficient when the jet exit to target spacing is more than the jet diameter. Confined or submerged multi jet configurations are also most suited for a closed loop system and such heat exchangers have been designed and tested by various researcher [14][15][16]. Fundamental studies on the thermohydraulics of a single submerged jet have been performed by Garimella and coworkers [17][18][19].…”

“…Panda and Prasad [14] compared the performance of a five jet heat sink with a single jet with air as the heat transfer medium. For a fixed Reynolds number of 9500, the five jet heat sink gave more uniform surface temperature distribution than a single jet.…”

Coupled Laminar Natural Convection and Surface Radiation in Partially Right Side Open Cavities

“…Gnanasekaran and Balaji (2011) developed a correlation for Nusselt number under turbulent mixed convection using transient heat transfer experiments. Panda and Prasad (2011) studied conjugate heat transfer from a flat plate with shower head impinging jets. Gonzalez et al (2012) made a numerical study of heat transfer by natural convection and surface thermal radiation in an open cavity receiver.…”