Numerical simulation of thermal hydraulics around a beam window in accelerator-driven system

加速器駆動未臨界システムにおけるビーム窓周りの熱流動解析

山下 晋   ; 吉田 啓之  

Yamashita, Susumu; Yoshida, Hiroyuki

加速器駆動未臨界システムのビーム窓周りの詳細な熱流動場を解析するために、多相多成分熱流動解析コードJUPITERを用いて非定常解析を実施した。その結果、流れ場は、従来の定常流を仮定した解析結果と比較して、ビーム窓周りの流れ場とノズル間の流れ場において非常に乱れた乱流場が形成されることを確認した。この乱れた流動場に応じて、ビーム窓における温度分布も同様に複雑な分布を示すことを確認した。したがって、複雑な流動場がビーム窓の温度分布に影響を与えることが確認でき、かつ流れ場が温度場に与える影響を評価しなければならないことが示唆された。

To investigate detailed flow behaviors around the beam window of accelerator driven system (ADS), large scale simulation for unsteady thermal hydraulics around the beam window was performed using JUPITER. The input data, such as the beam window and nozzle, is designed as accurate as possible using the computer aided design software. As a result, the flow pattern around the beam window is quite different from previous results in which the steady flow is assumed. The flow pattern of the Lead-Bismuth Eutectic around the beam window and the exit of the nozzle were very complicated. According to complicated flow around those structures, the temperature distribution on the beam window is also complicated. Thus, it is confirmed that the complicated flow around structures will affect to the temperature distribution in the structures and the effect of flow field on the temperature must be evaluated.