Mixed convection in a square cavity due to heat generating rectangular body

Abstract

Flow in the cavity with heat generating body finds wide domestic and industrial applications. The heat transfer characteristics and the irreversibility generated in the cavity depend on mainly the cavity size, aspect ratio of the heat generating body, and inlet/exit port locations. In the present study, effect of exit port locations on the heat transfer characteristics and irreversibility generation in a square cavity with heat generating body is investigated. A numerical simulation is carried out to predict the velocity and temperature fields in the cavity. To examine the effect of solid body aspect ratio on the heat transfer characteristics two extreme aspect ratios (0.25 and 4.0) are considered in the analysis. Fifteen different locations of exit port are introduced while air is used as an environment in the cavity. It is found that non-uniform cooling of the solid body occurs for exit port location numbers of 13 and beyond. In this case, heat transfer reduces while irreversibility increases in the cavity. These findings are valid for both aspect ratios of the solid body. Nomenclature A = cross-sectional area of solid body (m 2 ) a = aspect ratio b = length of protruding body (m) c = height of protruding body (m) h = heat transfer coefficient (W/m 2 K) I = irreversibility (W/m 3 ) k = thermal conductivity (W/mK) l = hydraulic radius of the solid body (m) Nu = Nuselt number P = pressure (Pa) P T = wetted perimeter of solid body (m) Ra = Rayleigh number HHH = volumetric entropy generation (W/ m 3 K) T = temperature (K) u = velocity in x-axis (m) v = velocity in y-axis (m) x = distance in x-axis (m) y = distance in y-axis (m) Greek symbols = thermal diffusivity (m 2 /s) = expansion coefficient (K ±1 ) " = viscosity (N.s/m 3 ) ) = kinematic viscosity (m 2 /s) & = density (kg/m 3 ) Subscripts F = fluid s = solid w = wall o = reference IntroductionMixed convection in a cavity receives considerable attention due to its importance in many engineering applications. Some of these include energy transfer in rooms and units, and cooling of industrial machines and electronic

Simulation of mixed convection heat transfer in a horizontal channel with an open cavity containing a heated hollow cylinder

“…They concluded that both the heat transfer coefficient and the dimensionless temperature in the body center strongly depend on the configurations of the system. Shuja et al [4] numerically studied mixed convection in a square cavity due to a heat generating rectangular body and investigated the effect of exit port locations on the heat transfer characteristics and irreversibility generation in the cavity. They showed that the normalized irreversibility increased as the exit port location number increased and the heat transfer from the solid body was enhanced while the irreversibility was reduced.…”

Pulsating flow and convective heat transfer in a cavity with inlet and outlet sections

“…For this geometry, the authors performed a series of computations covering a rather wide range of Strouhal numbers (from 0.1 to 10) and they report that, in all cases, heat transfer is enhanced when inlet flow oscillation is enforced. Steady mixed convection inside a cavity where a heated rectangular cylinder is present has been analysed by Shuja et al [11]. In particular, these authors focussed on the influence of the heated body size and the position of the exit port.…”

Effective cooling of stacked heat-generating bodies in a large room: Comparison between floor and side-wall air injection

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