内包流体の温度成層化により円筒容器に生じる熱応力の評価線図

Evaluation charts of thermal stresses in cylindrical vessels induced by thermal stratification of contained fluid

古橋 一郎*; 川崎 信史 ; 笠原 直人

Furuhashi, Ichiro*; Kawasaki, Nobuchika; Kasahara, Naoto

内包流体の温度成層化により円筒容器に生じる熱応力の簡易評価の高精度化を目的に、流体との熱伝達及び熱伝導を考慮した容器の定常温度解析及びその結果を用いたシェル応力解析を行い、以下の結果を得た。ステップ状あるいはランプ状の流体温度に対し、容器の板厚平均温度は温度減衰係数bを用いて高精度に評価できる。容器の熱応力は係数比b/(シェル係数)と無次元成層区間巾Lのみに依存する。この特性を利用して、容器の最大熱応力及びその発生位置を求める線図を作成した。線図を用いることにより、容器の定常熱応力の高精度の簡易評価が可能となった。設計コストの低減と設計合理化に寄与するであろう。

Temperature and thermal stress in cylindrical vessels were analysed for the thermal stratification of contained fluid. Two kinds of temperature analysis results were obtained such as the exact temperature solution of eigen-function series and the simple approximate one by the temperature profile method. Furthermore, thermal stress shell solutions were obtained for the simple approximate temperatures. The simple temperature solution is described by one parameter that is the temperature decay factor. The thermal stress shell solutions are described by two parameters. One is the ratio between the temperature decay factor and the load decay factor. Another is the non-dimensional width of stratification. These solutions are so described by few parameters that those are suitable for the simplified thermal stress evaluation charts. These charts enable quick and accurate thermal stress evaluations of cylindrical vessel of this problem compared with conventional methods.