The present paper deals with what we have studied about the heat transfer between the gas flowing through the granular layer and the wall surface of the following types of the apparatvs: (1) the annular type, where heat transfer occurs both through the inner and the outer walls, and (2) the outer-catalyst type, which is also annular, but in which heat transfer occurs only through the inner wall, the outer wall being thermally insulated.
The theoretical temperature distributions were calculated mathematically, and Eqs. (13) and (17) were obtained for the annular type and the outer-catalyst type, respectively. Fig 1, and Fig. 2 represent the axial temperature distribution, when no chemical reaction takes place calculated by Eqs. (8) and (19) respectively, while Fig. 3 and Fig. 4 represent the same calculated byEqs. (13) and (17), taking the temperature of the wall and the inlet gas as equals.
In Fig. 5 maximum temperature rises in the following types of apparatus are shown in comparison: (1) the annular type, (2) the outer-catalyst type, and (3) the cylindrical type. Since the figure shows the effects of various factors upon the maximum temperature rises for these three types, when the maximum temperature in one type is experimentally determined, those for the other two types wlll be successfully predicted, facilitating us in designing the apparatus of different types.
Applying the similar method to our study previously reported (Chem. Eng., Japan, 12 58 (1948)), the heat transfer in the annular type layer was experimentally studied.
λ, 1/b(=h'R/λ) and h were calculated, and they were compared with those for the simple cylindrical type. The results were as follows;
(1) λ/k can be represented by Eqs. (25) and (26) like in the cylindrical type.
(2) b can also be represented by Eq. (29) like in the cylindrical type, taking the equivalent dia.as (D
eq.=D
2-D
1). In the previous paper b was represented by Eq. (30), which was not perfectly nondimensional; but now we have found that Eq. (29) can also be applied in the case of the cylindrical type.
(3) For (h
∞D/k), Eqs. (31) and (32) were obtained; they were found to be about 30-50% greater than those for the cylindrical type in the conditions, Re
k=100 and d
k/D
eq.=0.1-0.03.
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