1 0 0 0 OA 多孔質金属フィンの沸騰熱伝達率特性
- 著者
- 近藤 義広 越田 博之
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- 日本機械学会論文集 (ISSN:21879761)
- 巻号頁・発行日
- vol.84, no.858, pp.17-00438-17-00438, 2018 (Released:2018-02-25)
- 参考文献数
- 12
Porous metal fin was used as boiling heat transfer plate of phase change devices. The number of cells of the porous metal fin is 8 ppi, and the pore diameter of the porous metal fin is 3.1 mm. On the boiling heat transfer surfaces, the porous metal fin and the bass plate are brazed. Three samples of boiling heat transfer plates with the porous metal fin were made as prototype. For HFE7000 and HFE7100 made by 3M Company as working fluid, the boiling heat transfer coefficient of the boiling heat transfer plate with porous metal fin with surface roughing process by ultrasonic wave is 15 kW/m2・K. And the vale is 2.5 times of the boiling heat transfer coefficient of the flat plate without fin. Predicting method of the boiling heat transfer coefficient to which the expansion ratio of effective area for the flat plate was added to correlation of the boiling heat transfer coefficient of Stephan’s equation. The boiling heat transfer coefficient in the heat transfer plate with surface roughing process by ultrasonic wave can be put in order by ± 10 %.
1 0 0 0 2016 屈曲風路構造の圧力損失
We have developed a method of cooling high-power-density CPU modules within a bending duct. The method uses a jet-duct system made of an air duct and axial fans. This system has slit orifices upstream from the CPU modules. Pressure drops in this system are calculated as four values : wringing loss in the chamber, friction loss in the duct, extrusion loss from the duct, and wringing loss in the slit orifice. These loss values agree with the experimentally measured losses to within an error of ±10%. The calculation showed that when the duct width is small, the wringing loss in the chamber account for the major part of the total loss.
1 0 0 0 2016 屈曲風路構造の圧力損失
We have developed a method of cooling high-power-density CPU modules within a bending duct. The method uses a jet-duct system made of an air duct and axial fans. This system has slit orifices upstream from the CPU modules. Pressure drops in this system are calculated as four values : wringing loss in the chamber, friction loss in the duct, extrusion loss from the duct, and wringing loss in the slit orifice. These loss values agree with the experimentally measured losses to within an error of ±10%. The calculation showed that when the duct width is small, the wringing loss in the chamber account for the major part of the total loss.
1 0 0 0 OA 電子機器冷却用熱コネクタの設計手法の検討
- 著者
- 林 知生 近藤 義広 豊田 浩之 佐藤 重匡 椿 繁裕
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- 日本機械学会論文集 (ISSN:21879761)
- 巻号頁・発行日
- vol.83, no.850, pp.16-00580-16-00580, 2017 (Released:2017-06-25)
- 参考文献数
- 10
We have developed the evaluation method for two performance factors to design the thermal connector: Insertion force of thermal grease and thermal conductance. The thermal connector was comprised of a thermal plug and a thermal socket, and the thermal grease which was filled into the gap between the thermal plug and the thermal socket connected the thermal plug and the thermal socket thermally. Firstly, the insertion force was theoretically calculated using the Bingham plastic model for rheology characteristics of the thermal grease and the slip model on the surfaces of the thermal plug and the thermal socket. The calculated results were in good agreement with the experimental results. Secondly, the experimental results of the thermal conductance between the thermal plug and the thermal sockets at the first connection to the 20 times connection were -1 to +26 percent greater than the theoretical value. The reason why some experimental results exceed the theoretical results is the eccentricity between the thermal plug and the thermal socket. In addition, the filling status of the thermal grease in the gap was visualized by ultrasonic testing. The results after the 20 times connections showed there were some voids in the thermal grease and the area of voids was 4 percent of the heat transfer area. Therefore, the thermal conductance was mostly not influenced by the voids. Finally, it was found that the proposed methods to predict the insertion force and thermal conductance were reasonable.
1 0 0 0 OA 多孔質金属フィンの圧力損失と熱伝達率の予測法
- 著者
- 近藤 義広 越田 博之
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- 日本機械学会論文集 (ISSN:21879761)
- 巻号頁・発行日
- vol.82, no.844, pp.16-00173-16-00173, 2016 (Released:2016-12-25)
- 参考文献数
- 10
- 被引用文献数
- 1
In order to evaluate the cooling performance of the porous metal fins, both the friction factor and heat transfer coefficient were taken into account. In this study, we compared six porous metal fins and four kinds of heat exchangers made of porous material. Moreover, we proposed a new model which predicts the cooling performance of the porous metal fins. Friction loss factor of porous metal fins became predictable in less than ±10% error by using effective cross-sectional flow area and Ergun coefficient in Forchheimer-extended Darcy model. Heat transfer coefficient of porous metal fins can be predicted within an error of 10% by our model. The predictive model has two assumptions. One is that the perimeter in the porous metal fin per cross-sectional area of porous metal fin is independent of the heights of fins and number of porous cells. Another assumption is that heat transfer coefficient of porous metal fin is also independent of the heights of fins and number of porous cells as long as the velocity is same.