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• 1. [Article] An analytical model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed

  A steady gas convection model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed is presented. Contributions due to flow within attached bubbles as well as the interstitial voids ...

  Citation × Citation Citation Abstract Copy Title: An analytical model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed Author: Adams, Ronald Lynn A steady gas convection model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed is presented. Contributions due to flow within attached bubbles as well as the interstitial voids are included. The interstitial flow is approximated as flow within a series of double cusped channels and the resulting three-dimensional boundary layer flow is analyzed using a Stokes approximation for the corner flow which is simply matched to a two-dimensional integral analysis of the central region. Effects of interstitial turbulence are included but gas property variations are neglected. Radiation heat transfer from the hot particle surfaces is included so that results at combustion temperatures can be obtained. A computer program is developed and used to obtain results for the case of a horizontal cylinder immersed in a bubbling two-dimensional atmospheric pressure bed. The interstitial gas flow for this case is obtained using complex analysis to determine the pressure field near the cylinder with bubbles present. Generally, the presence of a single bubble, having a diameter equal to the cylinder diameter, has a relatively small effect on the total heat transfer but significantly affects the local Nusselt number distribution. The heat transfer coefficients calculated using the model were found to be within the range of experimental results obtained by others, but more detailed experimental work is required to completely validate the model. The assumptions of the model are expected to be valid for mean particle diameters greater than 2-3 mm. Title: An analytical model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed Author: Adams, Ronald Lynn A steady gas convection model of heat transfer to a horizontal cylinder immersed in a gas fluidized bed is presented. Contributions due to flow within attached bubbles as well as the interstitial voids are included. The interstitial flow is approximated as flow within a series of double cusped channels and the resulting three-dimensional boundary layer flow is analyzed using a Stokes approximation for the corner flow which is simply matched to a two-dimensional integral analysis of the central region. Effects of interstitial turbulence are included but gas property variations are neglected. Radiation heat transfer from the hot particle surfaces is included so that results at combustion temperatures can be obtained. A computer program is developed and used to obtain results for the case of a horizontal cylinder immersed in a bubbling two-dimensional atmospheric pressure bed. The interstitial gas flow for this case is obtained using complex analysis to determine the pressure field near the cylinder with bubbles present. Generally, the presence of a single bubble, having a diameter equal to the cylinder diameter, has a relatively small effect on the total heat transfer but significantly affects the local Nusselt number distribution. The heat transfer coefficients calculated using the model were found to be within the range of experimental results obtained by others, but more detailed experimental work is required to completely validate the model. The assumptions of the model are expected to be valid for mean particle diameters greater than 2-3 mm. Close