Improvement on Superconducting Magnet Performance using Fountain Effect of Superfluid Helium

利用超流氦喷泉效应改进超导磁体性能

• 批准号: 12650193
• 负责人: OKAMURA Tetsuji
• 金额: $ 2.3万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650193/
• 关键词: Superfluid helium; Fountain effect; λ-transition; Porous material; Cooling channel; Superconducting magnet; λ転位; 超伝道磁石

Heat transport characteristics of superfluid helium (He n) in channel segmented by different types of spacer having several holes have been investigated on the basis of both experiment and numerical analysis. The heat transport performance has been examined for the following spacers : (a) FRP spacer without any hole, (b) FRP spacer with several holes of 2 or 4 mm diameter, (c) porous spacer made of fine powder of sintered Al_2O_3, (d) porous spacer made of high density polyethylene (HDPE) which is more flexible than Al_2O_3. The average diameter of the porous is about 1μm. It is expected that helium flow is induced in the channel because of a fountain effect when the porous spacer is applied.The λ-transition heat flux when we use the spacers having holes of diameter 2 mm and 4 mm is almost the same. This value is about 1.5 times larger than that in the case of using spacer without any hole. The λ-transition heat flux depends on the porosity of the spacer. A relatively high cooling performance can be realized when the porosity is only about 5%. These results lead to the understanding that the introduction of some holes in the spacer is a very effective way to suppress local temperature rise in the He II channel.The λ-transition heat flux increases remarkably when the porous spacer is used instead of the FRP spacer with holes of 2 or 4 mm in diameter, because Hen flow is induced in the heated channel by a fountain effect. It is also found that the use of porous spacers between Hell channels is effective to suppress a steep temperature rise in the heated channel not only when the channel is filled with He II entirely but also when normal helium (He I ) is generated in the channel.

基于实验和数值分析，研究了由不同类型的具有多个孔的间隔件分割的通道中的超流氦（He n）的热传输特性。已经检查了以下间隔件的热传输性能：（a）FRP。无孔隔板，(b) 具有多个直径为 2 或 4 mm 孔的 FRP 隔板，(c) 烧结 Al_2O_3 细粉制成的多孔隔板，(d) 高密度多孔隔板比 Al_2O_3 更柔韧的聚乙烯 (HDPE) 多孔的平均直径约为 1μm。当使用多孔间隔件时，由于喷泉效应，预计会在通道中引起氦流。λ 跃迁热通量。当我们使用直径为 2 mm 和 4 mm 的垫片时，该值几乎是使用没有任何孔的垫片时的值的 1.5 倍。热通量取决于间隔件的孔隙率，当孔隙率仅为5%左右时，可以实现相对较高的冷却性能。这些结果表明，在间隔件中引入一些孔是抑制局部的非常有效的方法。 He II 通道中的温度升高。当使用多孔垫片代替直径为 2 或 4 mm 的 FRP 垫片时，λ 跃迁热通量显着增加，因为通过喷泉效应在加热通道中引起 Hen 流。这是还发现，不仅当通道完全充满 He II 时，而且当通道中产生普通氦气 (He I) 时，在地狱通道之间使用多孔隔离物也能有效抑制加热通道中的急剧温度升高。

项目成果

先崎綾衣, 高橋雅人, 岡村哲至, 福田研二: "HeIIの鉛直流路内での伝熱解析"第65回低温工学・超電導学会予稿集. 157 (2001)

Aya Senzaki、Masato Takahashi、Tetsuji Okamura、Kenji Fukuda：“HeII 垂直通道中的传热分析”日本学会第 65 届低温工程和超导学会会议记录，157（2001）

関口基之, 末包哲也, 岡村哲至, 平井秀一郎: "λ転移を伴う液体ヘリウムの対流・伝熱シミュレーション"第37回目本伝熱シンポジウム講演論文集. 497-498 (2001)

Motoyuki Sekiguchi、Tetsuya Suekane、Tetsuji Okamura、Shuichiro Hirai：“液氦中对流和传热的 λ 跃迁模拟”第 37 届传热研讨会论文集 497-498 (2001)。

M.Takahashi, A.Senzaki, T.Murakami, T.Okamura: "Improvement on Cooling Performance in Hell Channel Using Fountain Effect"Proc. of 17^<th> International Conference on Magnet Technology. 131 (2001)

M.Takahashi、A.Senzaki、T.Murakami、T.Okamura：“利用喷泉效应改进地狱通道的冷却性能”Proc。

先崎綾衣, 高橋雅人, 岡村哲至, 福田研二: "HeIIの鉛直流路内での伝導解析"第65回低温工学・超電導学会予稿集. 157 (2001)

Aya Senzaki、Masato Takahashi、Tetsuji Okamura、Kenji Fukuda：“HeII 垂直通道中的传导分析”第 65 届日本低温工程和超导学会会议记录，157 (2001)

T.Okamura, M.Takahashi, D.Muramatsu: "Effect of Superfluid Helium Channel Configuration on the Heat Transport Characteristics"Proc. of the 6^<th> Cryogenics 2000 IIR International Conference. 38-41 (2000)

T.Okamura、M.Takahashi、D.Muramatsu：“超流氦通道配置对热传输特性的影响”Proc。