低温下LNG储罐混凝土外罐的静力性能分析

Mechanical behavioral of LNG outer concrete tank under low temperature

以160 000 m3液化天然气LNG储罐混凝土外罐为研究对象,借助ANSYS有限元,针对LNG低温液体发生泄漏时,在低温作用下的受力与变形性能展开模拟研究,获得了稳态对流换热条件下的温度场及其温度应力分布.采用热-固耦合分析方法,将低温液体作用下的混凝土外罐罐壁处的温度应力与其他静力荷载作用下的内力进行了不同工况下的内力组合,确定了结构的最不利内力包络图,并以此为依据对LNG储罐混凝土外罐罐壁进行了预应力钢筋的配筋计算与布置.研究结果表明:低温液体下产生的温度应力使LNG储罐混凝土外罐发生整体向内收缩变形的趋势;罐内液体压力对结构内力及变形起主导作用;满液位泄露时LNG储罐混凝土外罐的薄弱部位位于距底板约10 m高度处.

To offer the distribution of the temperature field and thermal stress for steady state convective heat transfer condition of LNG tanks on leakage occasion, the behaviors of a 1 600 000 m^3 LNG outer concrete tank are studied by ANSYS. Via thermal-structure coupling analysis, cases combinations between the thermal stress on LNG outer concrete tank wall and different static forces are calculated. The most adverse envelope diagram under static load is obtained, and then the configuration of circumferential pre-stressed reinforcement is proposed. The numerical results show that the temperature stress makes the LNG outer concrete tank a shrinkage deformation tendency; the liquid pressure is the dominating influence factor on deformation and internal forces of the outer tank structure; the weakest part is located at about 10m from the bottom.