LNG沉浸式气化器的数值模拟  

Numerical simulation on LNG submerged vaporizer

作　　者：毕明树[1] 窦兴华[1] 

机构地区：[1]大连理工大学化工学院

出　　处：《天然气工业》2009年第1期109-110,113,共3页Natural Gas Industry

基　　金：辽宁省高校重点实验室基金(编号:20060129)的资助

摘　　要：液化天然气调峰系统中常用沉浸式气化器。与普通换热器相比,LNG沉浸式气化器有很多特殊性。为实现LNG沉浸式气化器的合理设计,必须掌握其内的两相流动流场及其传热特性,而LNG沉浸式气化器内流体流动和换热方面的数值模拟尚未见报道。在分析、组合其他模型的基础上,建立了LNG气化器内流动与传热过程的物理和数值模型,用标准湍流模型描述流体的湍流流动,用混合物模型处理多相流动,用离散相模型描述射流气体与水浴的相间耦合计算,用UDF函数添加源项方法描述液体气化过程,对LNG沉浸式气化器进行了三维数值模拟。获得了管程LNG气化过程中气、液相分布和流动情况,讨论了换热管倾斜角、射流气体雷诺数、射流喷嘴与换热管相对位置对气化过程的影响。结果表明,换热管向上倾斜2°以上可避免产生气阻现象;喷嘴射流气雷诺数在50000左右、喷嘴与换热管同位布置换热效率最高。The submerged vaporizer,commonly used in peaking system of LNG,has many different features compared to the conventional heat exchanger. It is necessary for engineers to have a full knowledge of heat transfer and two-phase flow field in order to have perfect design on the submerged vaporizer,but till now there is no published documents about numerical simulation on this case. Therefore,this study built up a physical and mathematical model of LNG submerged vaporizer,in which the turbulent flow was described with standard k-ε model,and the multiphase flow with mixture model,the couple calculation between the gas phase and the water phase with discrete phase model,the process of vaporization with UDF function. In this way,a 3D numerical simulation on flow and heat transfer process in LNG submerged vaporizer was carried out. The vapor and liquid phase distributions during vaporizing of LNG along pipes are described. The effects of sloping angle of tube,Reynolds number of jetting gas and the relative array between nozzles and tubes on vaporizing are discussed. The results provide foundation for the design of LNG Submerged vaporizer. The results show that the vapor choke can be avoided by sloping the pipes up to 2°and above; and the heat exchanging efficiency reaches its maximum when the Reynolds of jet gas from nozzles is about 50000 with arranging nozzles in the same line with heat pipes.

关 键 词：液化天然气 气化 两相流动 数值模拟 

分 类 号：TU996[建筑科学—供热、供燃气、通风及空调工程]