天然液化气储罐中Rayleigh-Benard细胞流的形成及流动分析

Formation of Rayleigh-Benard cell stream and flow analysis in natural liquefied gas storage tank

为了研究在天然液化气储罐内Rayleigh-Benard(RB)细胞流的形成过程以及流动情况,以宽长比为1∶4的矩形来表征液化气储罐横切面,采用数值模拟方法在矩形中形成RB流。分析模拟结果表明:用流函数等值线变化来表征RB对流从无到有的形成过程;RB对流稳定条件为中心点流体速度达到最大并不发生变化;随着Ra增大,等温线弯曲程度越大,所以对流强度用Ra大小来表示;旋涡形成规律为无论矩形宽长比是奇数或偶数,旋涡总是成对出现,并且涡的大小分别为大于1小于2的单位长度或一个单位长度;在逆时针旋涡中心流体速度最大,顺时针旋涡中心流体速度最小,速度分布具有一定周期性。结论可给天然气液化储罐的安全运输与储存的防爆提供有效措施。

In order to study the formation of Rayleigh-Benard （RB） cell flow and liquidity situation in natural liquefied gas storage tank, and to characterize the liquefied gas storage tank rectangular cross-section of 4 ： 1 ratio of length to width, RB was formed by numerical simulation flow in the rectangle. Analysis of the results showedthe following conclusions： with changes in stream function contours to characterize the flow cell formation process from scratch; RB convection stable condition is that the center point of the fluid reaches the maximum and speed is not changed; as Ra increases, the greater the degree of bend isotherms so convection intensity is represented by Ra size; formation law of vortex is that whether rectangular aspect ratio is odd or even, vortex always appear in maximum velocity of the fluid is in the counter-clockwise vortex center, the minimum velo pairs; the city of the fluid is in the clockwise vortex center; velocity distribution has a certain periodicity; and the size of the vortex is greater than one less than two or equal to one. Analysis results and then provide effective anti-explosion measures for safe transport and storage of liquefied natural gas storage tanks.