Numerical study on pressure wave propagation in a mercury loop

水銀ループ中での圧力波伝播挙動に関する数値解析

粉川 広行  ; 長谷川 勝一   ; 二川 正敏  ; Riemer, B.*; Wendel, M.*; Haines, J.*

Kogawa, Hiroyuki; Hasegawa, Shoichi; Futakawa, Masatoshi; Riemer, B.*; Wendel, M.*; Haines, J.*

水銀ターゲットの圧力波問題に関して、ロスアラモス研究所の陽子加速器を用いたオンビーム実験を実施し、キャビテーション損傷評価とともにループターゲットのひずみ計測を行った。陽子ビーム照射位置から350mm離れた位置での最大ひずみは、陽子ビーム照射後5.5msで発生し、その伝播速度は、応力波や圧力波の伝播速度(それぞれ、5000m/s, 1500m/s)よりも遅い65m/sであることがわかった。数値解析を行い、伝播速度の低下は、水銀とループ壁の相互作用によることを明らかにした。

In beam test was carried out at the LANSCE-WNR to investigate pressure wave mitigation in mercury targets for the MW-class spallation neutron sources under international collaboration between SNS and JSNS. A mercury loop with micro bubble generator was used for the target. The loop target consists of the rectangular pipe which was made of stainless steel. The total length of the loop is about 2 m. Strain sensors were set on many points of loop to measure the strain on the pipe wall caused by the pressure wave. The maximum strain at 350 mm apart from the proton bombarded point appeared after 5.5 ms after the proton bombardment. The wave propagation velocity was slower than the stress wave and the pressure wave propagation velocities and became 65 m/s in the IBBTL. Numerical analysis result shows that the maximum strain at 350 mm apart from the proton bombarded point appeared at 5.5 ms after proton bombardment as well as the experimental due to interaction between liquid and solid.