Heat Transfer of Granular Catalysts
VIII Experiments on the cases of various packings
1953 Volume 17 Issue 7 Pages 276-283
Details
1953 Volume 17 Issue 7 Pages 276-283
Theoretical equations of heat transfer between the gas flowing through granular solids and the cylindrical wall, has already been studied and checked by experiments, using cylindrical catalysts both. with and without chemical reaction. (Rep. I-VII) The present paper deals with the experiments on various types of packings.
Hot air (ca. 200°C) was passed through a cylindrical packed tower whose wall was kept at constant temp. by boiling water, and the axial temp. distribution within the layer as well as the average temps. of the gas at the inlet and the outlet were measured. The turbulent conductivity (effective cond.) λ, the film coeft. based upon the true film temp. of the wall h' and that based upon the average temp. h were calculated. The experimental ranges were as follows (length in mm):
From, these the following results were obtained.
1) In regard to these packings, the observed temps. of the average tm and the center tc at the exit of the packed layer varied appreciably according to some incidental changes of the packed condition, and λ/k, 1/b, and h∞D/k, could not be satisfactorily correlated by any nondimensional formula but what are given in Table 8·2 and eq. (48) (length in [m]). 2) Assuming D is constant, λ/k and h∞D/k have the maximum value for an optimum value of dk/D. These values of dk/D are 0.227-0.325 for λ/k and 0.13-0.273 for h∞D/k. 3) dk/D, the wall effect, has an effect upon h∞D/k, 1/b and also upon λ/k (which was not effected in the case of cylindrical packing).
