engleski

Heat Transfer Coefficient Analysis between Fluidised Bed and Horizontaly Immersed Coil

Values of heat transfer coefficients measured at the surface of a spirally shaped pipe coil, horizontally immersed into an air-corundum fluidised system, are presented in the paper. During the experiments, the fluidised bed was operating in the optimal range of gas velocities where maximum bed side heat transfer coefficients are obtained. The pipe coil is fed with hot water which is cooled by the fluidised bed, in which the coil was fully submerged. The tests were performed using three different corundum granulations: 0.185, 0.370 and 0.745 mm. For comparison, the measurement of the heat exchange for the same model and pure gas convention, when the pipe coil is cooled only with pure air was also performed. The measured maximum heat transfer coefficients are in accordance with the values calculated by means of the often-used Zabrodsky formula. Nondimensional correlation function for the investigated fluidization ranges was obtained by means of mathematical computation.

heat transfer coefficient; immersed coil; fluidised bed

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