社団法人日本機械学会 Acta Medica Okayama 0387-5016 62 596 1996 比較的大きな球状粒子を充填した下面加熱・上面冷却を受ける水平粒子層の対流熱伝達 : 第2報, 充填層厚さの影響 208 215 EN Koichi Ozaki Hideo Inaba Convection heat transfer and pressure drop measurements were performed with a rectangular duct, having a cooled upper and a heated lower surface, which was packed with spherical particles. Air was used as the test fluid and four kinds of spherical particles having different diameters and thermal conductivities were used as the packing materials. The ratio of the diameter of the spherical particle to the distance between the cooled and the heated surfaces, d/H, was varied from 0.173 to 1. The thermal conductivity of the particle layer was also measured under the still air condition. The thermal conductivity of the particle layer was not affected by the value of d/H. In the case of the one stage arrangement of spherical particles (d/H = 1), the flow resistance took on a remarkably small value compared with the flow resistance of a homogeneous spherical particle layer. Moreover the flow resistance of the particle layer formed with some layers of particles was able to be predicted by combining the flow characteristic of the one stage particle layer and that of the homogeneous spherical particle layer. The heat transfer coefficient of the particle layer was larger than that of turbulent air flow on a flat plate. At a constant superficial air velocity, there existed the value of d/H which gave a maximum value of the average heat transfer coefficient. Nondimensional heat transfer correlation equations were derived in terms of parameters expressing the average characteristics of the spherical particle layers. No potential conflict of interest relevant to this article was reported.

社団法人日本機械学会 Acta Medica Okayama 0387-5016 62 596 1996 平板状形状安定化潜熱蓄熱材充填矩形蓄熱槽の非定常熱特性 : 蓄熱過程における諸因子の効果 296 303 EN Hideo Inaba Ping Tu Transient characteristics of a ractangular latent heat storage vessel packed with shape-stabilized phase change (solid-liquid) material(PCM) are investigated numerically with the finite difference technique. It is found that the heat storage characteristics are greatly affected by the flow direction of the heat transfer medium since the natural and forced convection coexist in the heat storage vessel, That is, it is clarified that the effective thermal efficiency of the latent heat storage system is obtained with downward flow along a vertical PCM for the heat storage process. The effects of the inlet velocity and the inlet temperature of the heat transfer medium on transient heat characteristics of the latent heat storage system are also revealed in the present study. No potential conflict of interest relevant to this article was reported.