Mehdi Ashjaee; Hossein Shokouhmand; Mehdi Amiri; Touraj Yousefi
Abstract
Laminar free convection heat transfer from vertical and inclined arrays of horizontal isothermal cylinders in air was investigated experimentally and numerically. Experiments were carried out using Mach-Zehnder interferometer and the FLUENT code was used for numerical study. Investigation was performed ...
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Laminar free convection heat transfer from vertical and inclined arrays of horizontal isothermal cylinders in air was investigated experimentally and numerically. Experiments were carried out using Mach-Zehnder interferometer and the FLUENT code was used for numerical study. Investigation was performed for vertical and horizontal cylinder spacing from 2 to 5 and 0 to 2 cylinder diameters respectively. The Rayleigh number based on the cylinder diameter varied between 103and 3×103.The effect of vertical and horizontal cylinder spacing and Rayleigh number on the local heat transfer from each individual cylinder was investigated. It was seen that the local heat transfer coefficient of each cylinder strongly depends on its position relative to the others. This variation of the local heat transfer coefficient was explained by the interaction of plume's temperature and velocity profiles.
Mehdi Ashja'ee; Touraj Yousefi; Hossein Shokouhmand
Abstract
An experimental and numerical study of free convection heat transfer from a channel consisting of a vertical sinusoidal wavy surface and a vertical flat plate has been carried out. The vertical wavy surface was maintained at a constant temperature, while the flat plate is adiabatic. A Mach-Zehnder Interferometer ...
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An experimental and numerical study of free convection heat transfer from a channel consisting of a vertical sinusoidal wavy surface and a vertical flat plate has been carried out. The vertical wavy surface was maintained at a constant temperature, while the flat plate is adiabatic. A Mach-Zehnder Interferometer was used to determine the local heat transfer coefficients of sinusoidal wavy surface. FLUENT code was used for numerical simulation. The numerical results are in good agreement with experimental data. The amplitude-wavelength ratio, , in this investigation is kept constant at .The effects of Rayleigh number and wall spacing are investigated as well. Experiments were carried out for eight different Rayleigh numbers and thirteen different wall spacing. Results indicate that the frequency of the local heat transfer rate is the same as that of the wavy surface. The average heat transfer coefficient increases as the Rayleigh number, increases. For each Rayleigh number there is an optimum wall spacing where the heat transfer rate from the wavy sinusoidal surface reaches its maximum value. This optimum wall spacing depends on Rayleigh number and decreases with increasing Rayleigh number.