| A foam-filled channel having constant wall temperature and allowing convective cooling was numerically analysed to obtain the overall heat transfer coefficient and the characteristic length as the function of foam density, cell spacing, foam thickness, fluid velocity and physical properties of foam and fluid. It is found that the numerically calculated overall heat transfer coefficient shows negative deviation from one calculated by analytical model assuming constant fluid temperature along direction of foam thickness. The deviation was strong at small foam density, small cell spacing, high fluid velocity and thick foam, where heat conduction capacity through solid ligaments was low compared with solid ligament-fluid heat transfer capacity and the fluid temperature variation along direction of foam thickness was remarkable. A general expression for the characteristic length, which was proportional to mass flow rate per unit foam width, and inversely proportional to the overall heat transfer coefficient could be obtained. |
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