巻号一覧
15 巻 (1998)
- 4 号 p. 305-
- 3 号 p. 185-
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15 巻, 3 号
選択された号の論文の13件中1～13を表示しています
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論文
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平田 哲夫, 石川 正昭, 長坂 恒次1998 年 15 巻 3 号 p. 185-191
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーExperimental studies for freezing phenomena of ethylene glycol solution on cooled plate have been performed. A polyvinyl chloride as well as an acrylic resin plates are used for the cooled plates. It is found that the crystal ice formed at the cooled plate is removed from the plate due to buoyancy force acting the crystal ice. It means that ice formation on a cooled plate without deposit ice layer is possible by the present method. It is shown that the cooled plate surface is under cooled about 1.0~1.5 degree below the freezing temperature of the solution during the crystal ice formation and its removal phenomena. The degree of under cooled temperature is unaffected by the cooling temperature of the plate. For higher concentration of solution, it is found that the number of the removed crystal ice per unit time is increased and the volume of each removed ice is decreased.抄録全体を表示PDF形式でダウンロード (417K) -
河部 弘道, 福迫 尚一郎, 山田 雅彦, 柳田 弘毅1998 年 15 巻 3 号 p. 193-201
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーAn experimental study was conducted to investigate the continuous production characteristics of slush ice by use of a horizontal oscillating coo1ed wall immersed in a ethylene-glycol aqueous solution. Experiments were carried out for a variety of conditions such as acceleration velocity, motion stroke, and initial concentration of solution. It was found that two types of separating mechanisms of ice layer were observed due to the concentration of solution and the oscillation motion of the coo1ed wall, which suggests the possibility of continuous slush ice formation by the present method. The operating conditions for continuous production of slush ice were a1so determined.抄録全体を表示PDF形式でダウンロード (598K) -
斎藤 彬夫, 大河 誠司, 石井 剛人1998 年 15 巻 3 号 p. 203-212
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーIn relation to the transportation of supercooled water, transient solidification phenomena of supercooled water flow was studied, experimentally. Time dependency of the pressure, temperature and flow rate after appearing of ice in a pipe were measured. At the same time, ice growth phenomenon in a pipe was observed from the outside. The initial ice was set using a trigger port. When ice appeared in a pipe, it was found that ice grew on the inner surface towards the upstream direction. In the upstream, dendrite ice or ice similar to fleecy clouds were formed opposing the direction of flow. On the other hand, ice did not form at downstream at the beginning, but after appearance of ice-flake floating from the upstream sticking the inner wall at downstream. Relationship among freezing progress rate in the upstream direction, mean f10w velocity and temperature were examined. It was found that freezing progress rate depends only on the temperature at the inner surface and not the mean flow velocity. Finally, the mechanism of ice growth in a pipe until blockade was discussed.抄録全体を表示PDF形式でダウンロード (642K) -
水滴内部からの沸騰現象による過冷却解除効果佐藤 勲, 伏信 一慶, 橋本 優1998 年 15 巻 3 号 p. 213-220
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーIn this study, the feasibility of cooling/freezing of phase change.. materials(PCMs) due to evaporation for cold storage systems was experimentally examined. A pure water was used as the test PCM, since the latent heat due to evaporation of water is about 7 times larger than that due to freezing. A water droplet, the diameter of which was 1-4 mm, was suspended in a test cell by a fine metal wire (O. D.= 100μm),and the cell was suddenly evacuated up to the pressure lower than the triple-point pressure of water, so as to enhance the evaporation from the water surface. Temperature of the droplet was measured by a thermocouple, and the cooling/freezing behavior and the temperature profile of the droplet surface were captured by using a video camera and an IR thermo-camera, respectively. The obtained results showed that the water droplet in the evacuated cell is effectively cooled by the evaporation of water itself, and is frozen within a few seconds through remarkable supercooling state. When the initial temperature of the droplet is slightly higher than the room temperature, boiling phenomena occur in the droplet simultaneously with the freezing due to evaporation. Under such conditions, it was shown that the degree of supercooling of the droplet is reduced by the bubbles generated in the droplet.抄録全体を表示PDF形式でダウンロード (567K) -
大河 誠司, 斎藤 彬夫, 深尾 剛1998 年 15 巻 3 号 p. 221-228
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーThe effect of applying the electric charge on the freezing of supercooled water was investigated using a pair of spherical electrodes, facing to each other in the test water. The reason for using a spherical end surface was to minimize unexpected high electrical density on the surface due to the existence of a singular point. After getting a uniform temperature, D. C. voltage was applied to the test section. Temperature, distance between two electrode sand the voltage applied were varied. It was found that supercooled water freeze in a few seconds after applying the electric charge. It was also found that the freezing is a statistical phenomenon. There are some tendencies, however, that the higher the value of D. C. voltage applied or the closer the distance between two electrodes are, the easier the water freeze. The electrical current was measured for every 0.05 seconds and it was found that the value increased while the voltage was being applied. The idea of a probability of freezing while a specific current flows for a time interval of Δt was introduced. The probability of freezing was calculated under two different conditions and the results were compared to each other to confirm the assumption. As a result, it was concluded that the probability depends only on the past record of current flow.抄録全体を表示PDF形式でダウンロード (413K) -
岡田 昌志, 姜 〓東, 沖山 晴彦1998 年 15 巻 3 号 p. 229-236
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーA mushy region was formed by solidifying NaCl aqueous solution in a circular tube or a rectangular tube. The measurements of permeability were performed by changing volume fraction of liquid region in the mushy region. The dendritic ice in the solidification process was observed with a CCD microscope. The following results were obtained. The permeability increases with the volume fraction of liquid phase, and decreases with increasing the super-cooling degree of the solution or increasing the initial concentration of the solution, and is constant after the mushy region was formed. The arm space of dendrite becomes narrower as the super-cooling degree of the solution increases.抄録全体を表示PDF形式でダウンロード (401K) -
谷野 正幸, 小澤 由行, 井上 剛良, 高木 周1998 年 15 巻 3 号 p. 237-248
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーFor an air-conditioning system with ice storage, a calculation model taking into account of the physical processes of ice melting is necessary to predict the performance of peak-shift of the electric power. We already investigated experimentally the characteristics of ice storage and melting processes in a dynamic-type ice storage system by using super-cooled water. In this paper, we have proposed the calculation model of ice melting process applicable to practical uses. This model has taken into account of mass and heat balances in the ice-rich layer, and estimated quantitatively the effects of porosity, permeating water velocity in the layer and side wall of an ice storage tank. It has been confirmed that the time histories of outlet water temperature calculated by this model have agreed well with those obtained in real-scaled ice storage tanks. Moreover, the thermohydraulic behavior in the ice-rich layer has been able to be analyzed qualitatively in the ice melting process.抄録全体を表示PDF形式でダウンロード (607K) -
平田 哲夫, 石川 正昭, 北川 一栄1998 年 15 巻 3 号 p. 249-255
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーExperimental and analytical studies of ice formation process in water flow on a cold flat plate with heat conductor plates (HCP) have been performed. The HCP made of copper were located on the cold plate with clearance in parallel to water flow direction. The resulting ice thickness, which was affected by the heat conduction of HCP, was measured in a steady-state condition for the ranges of ReOH= 4330-32000 and cooling temperature ratio of θ=1.26-6.32. An analytical method for ice formation associated with comparatively large HCP spacing with convective water flow is proposed. The effects of spacing, thickness, height, and thermal conductivity of HCP on the ice volume fraction are investigated analytically. It is found that the HCP plays a role of either an augmentation or suppression of ice-accumulation in dependence on the experimental conditions.抄録全体を表示PDF形式でダウンロード (364K) -
平澤 良男, 中山 豊, 竹越 栄俊1998 年 15 巻 3 号 p. 257-263
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーThe authors have studied the phase change process of composite materials containing conductive solids in order to improve the heat transfer characteristics of phase change materials. In this study, numerical calculations using a finite differential method are carried out for solidification and melting processes of water in a tube-bank-type thermal energy storage vessel. The phase change volume, temperature distribution and flow field in the water are predicted. As a result, the solidification and melting processes are promoted considerably by heat conduction in fins, and it is found that the natural convection around the fins has large effects on the temperature profile in the water. The ice shape formed around the tube can be controlled by the dimension of the fins and the ice packing ratio can be increased by choosing an approximate dimension of the fins.抄録全体を表示PDF形式でダウンロード (519K) -
三戸 大介, 小澤 由行, 谷野 正幸, 斎藤 斉1998 年 15 巻 3 号 p. 265-274
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーEffects of ice bridging phenomena on ice-making characteristics of an ice-on-coil type thermal storage apparatus has been clarified, taking into account of two and three dimensional heat flow in analysis. These analytical results have agreed well with the experimental ones. Moreover, it has been possible to explain quantitatively not only both effects of geometrical and thermofluid dynamic conditions on the thermal performance after incipience of ice bridging, but also the development of ice bridging area. In the case of direct expansion type ice making, the ice making ability is strongly affected by the arrangement of the heat transfer tubes. On the other hand, in the case of brine type, though the local ice making ability is determined by the ice layer profile along the brine flow direction, the ability averaged in a whole of the ice storage tank is not so affected by the tube arrangement.抄録全体を表示PDF形式でダウンロード (525K) -
熊野 寛之, 斎藤 彬夫, 大河 誠司, 山田 雄一, 柴田 康二1998 年 15 巻 3 号 p. 275-283
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーIn this study, direct contact melting with asymmetric load is investigated experimentally and analytically. In experiment, rectangular parallelepiped PCM and rectangular heating plate were used so that the flow in the thin liquid film could be treated as the two dimensional problem in rectangular coordinates. The PCM on the heating surface was melted under various asymmetric loads, while total load acting on the PCM and brine temperature were kept constant. Then, time dependency of the height and the inclination of the PCM were measured. In analysis, the system was formulized and calculation was carried out, while the moment, the total load, the brine temperature ware set at constant values that were similar to the experimental conditions. The melting process progressed keeping the force balance between the pressure in the liquid and the loads at all times. As the result, it was found that an average heat flux into the PCM was independent of the moment acting to the solid and it was decided by the total load and the brine temperature, experimentally and analytically Moreover, analytical results of the time dependency of the melting amount and the inclination of the PCM coincided with experimental one for all conditions.抄録全体を表示PDF形式でダウンロード (453K) -
山田 雅彦, 福迫 尚一郎, 呉 〓1998 年 15 巻 3 号 p. 285-296
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーIn this paper the effects of flow separation both on the freezing heat transfer characteristics and on the pressure drop of a duct flow have been investigated. Under some condition of temperature and flow separation an ice-water interface in the presence of a turbulence has been observed to be complexed. The degree of flow separation was varied by employing the orifices of various heights at the inlet of the duct. In this study, the range of Reynolds number ReH coveredfrom 2.61×103 to 1.36×l04 and cooling temperature ratios to the water temperature from 2.0 to 30.0. Velocity profile and turbulence intensity distribution in the flow passage were measured using a Laser Doppler Velocimeter. The measurement results showed that the first and the second space of ice layer were strongly related to the flow separation by an orifice and that the stepped ice pattern after 2nd spacing ice-bands was very similar to the patterns which was observed in the case of pie flow.抄録全体を表示PDF形式でダウンロード (604K) -
直交一次元の解の性質とキーパラメータ浜松 照秀1998 年 15 巻 3 号 p. 297-303
発行日: 1998年
公開日: 2011/09/08
ジャーナル フリーA theoretical approach to heat conduction in phase changing solid with convective surface heat transfer has been tried to disclose the effect of the heat transfer, and to get the governing equation for the phase-changing front movement and the transient temperature field.
As a result of the analytical work in the rectangular heat conduction field, the quasi-theoretical solutions containing the Stefan's problem for the phase change front movement and the transient temperature distribution have been obtained, and in addition one of the key parameters newly introduced is a non-dimensional heat transfer factor. HTF (convective heat tranferrability vs. latent heat capacity) which can indicate the acceleration of phase change and the difference from the Stefan's solution.抄録全体を表示PDF形式でダウンロード (298K)
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