A numerical simulation of the flow of LNG stored in a small-sized cylindrical tank is presented. The main scope of this work is to characterize the heat ingress to the tank as well as the boil-off rate, depending on the filling level and the insulation layer thickness. The tank is assumed to be in a state of inactivity, such that the fluid phases are initially quiescent and are not released to the exterior. The proposed mathematical model consists of a conjugate heat transfer problem coupled with the SST $K-\omega$ turbulence model for the fluid phases. The free surface separating liquid and vapor in the tank is tracked using the Volume of Fluid method (VOF). The model is solved using the software ANSYS Fluent. It is shown that the filling level of the tank substantially influences the boiling rate and the degree of stratification, as well as the flow structures generated by free convection. The relation among the insulation thickness and total heat leak is established, showing that the obtained increased heat ingress due to lower insulation thickness values leads to a rise in pressurization and boil-off rates.

提出了存储在小型圆柱形罐中的液化天然气流量的数值模拟。这项工作的主要范围是根据填充液位和绝缘层厚度来表征进入罐的热量以及蒸发率。假定储罐处于不活动状态，因此流体相最初是静止的，不会释放到外部。所提出的数学模型包括与SST耦合的共轭传热问题$ķ-\omega$流体相的湍流模型。使用液体体积法（VOF）跟踪罐中分离液体和蒸气的自由表面。该模型使用软件ANSYS Fluent求解。结果表明，储罐的液位显着影响沸腾速率和分层程度，以及自由对流产生的流动结构。建立了绝缘厚度和总热泄漏之间的关系，表明由于较低的绝缘厚度值而获得的增加的热量进入导致加压和沸腾速率的增加。