流れを伴う充填層の伝熱に関する研究

抄録

In order to know the effects of wall temperature and thermal conductivities of packings on heat transfer mechanisms in packed beds, effective thermal conductivities k and overall heat transfer coefficients h_o were observed in packed beds of several kinds of solid, usinga calorized steel tube whose inner diameter was 52.9mm.
Packings
iron sphere llmm, insulating fire-brick granule 10mm,
cemenent clinker 6mm, 3.5mm; glass sphere 6mm
Range of experiments
wall temperature t_w=100-500°C
modified Reynolds number D_pG/μ=40-500
According to the experimetal result, the effective thermal conductivities in packed beds were found to depend upon both the mean temperature of bed and the thermal conduities of packings, as shown in Fig. 7, and the experimental data could be predicted fairly well from the author's theoretical equations [Eqs. (1) and (2)].
Overall heat transfer coefficient seemed not to be influenced so much by the wall temperature as shown in Fig.9.
Then, simplifying themechanisms of latcrial heat transfer in packed bed, approcximate equations [Eqs. (16) and (17)] were obtained, by means of which to discuss the relations among the effective thermal conductivity, film heat transfer coefficient and overall heat transfer coefficient. The adequacy of the above equations were proved by comparing (A) the values of film heat. transfer coefficient, calculated from the data on overall heat transfer by means of Eqs. (16) and (17), with (B) the data on film heat transfer coefficient ever repord a shown in Fig.10
Equation (19) for film heat transfer coefficient coincided fairly well with the data presented for packed beds of solid spheres.