ON THE LENGTH EFFECT OF THE HEAT DISPERSION PARAMETERS
Title:
ON THE LENGTH EFFECT OF THE HEAT DISPERSION PARAMETERS
Author:
Stanek, Vladimir Vychodil, Petr
Appeared in:
Chemical engineering communications
Paging:
Volume 27 (1984) nr. 1-2 pages 69-78
Year:
1984-04-01
Contents:
Considerable attention has been paid to the dispersion of heat in fixed beds passed by a flowing gas. This is best documented by ample experimental evidence and correlations available in the literature. However, the results of individual studies differ often significantly. As a possible cause of the discrepancies have been put forth various experimental techniques and data processing methods (Gunn, 1970; Froment, 1972; Li and Finlayson, 1977), particularly the use of different mathematical models. As a fact of considerable significance, however, remains the dependence of results on the geometry of the experiment. All parameters of the pseudohomogeneous one- and two-dimensional models have been found to depend on the length of the bed (Li and Finlayson, 1977; De Wasch and Froment, 1972; Bunell el al., 1949; Calderbank and Pogorski, 1957), while their values invariably decrease with the increasing length. In contrast, neither of the existing models predicts such a dependence, nor is there a satisfactory explanation for the phenomenon at hand. The aim of this work has been to carry out experimental measurements of the effective radial thermal conductivity in a fixed bed passed by flowing air and to analyze in detail the length dependence of the results. The experiments consisted of measurement of the steady state outlet temperature profiles corresponding to a radially distributed inlet profile.
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