低温储罐大流量回液冲击液面过程的数值模拟研究

Numerical investigation on submerged hydraulic jumps of cryogenic tank with large flow

针对某3000 m^(3)液氮储罐在2000 m^(3)/h的大流量回液与排液工况,建立了该储罐及其排液管路的计算流体力学(CFD)模型,着重分析了液氮回液冲击液面过程中的复杂气液界面演变与液体流动情况,并研究了防涡板和回液分流斗对液面波动的抑制作用。结果表明,大流量回液冲击液面过程易产生液面凹陷,若低于临界液位高度则导致排液中夹带气体。对临界液位高度影响因素的分析表明,设置防涡结构和削弱回液冲击是降低临界液位高度的主要优化方向。采用分流斗和防涡板结构可分别削弱回液冲击并抑制液面波动,最终可将临界液位高度降低到0.6 m以下。

For a 3000 m^(3)liquid nitrogen storage tank with a large flow rate of 2000 m^(3)/h,the computational fluid dynamics(CFD)model of the storage tank and its drainage pipeline was established.The evolution of complex gas-liquid interface and liquid flow in the process of liquid nitrogen impacting the liquid level were emphatically analyzed,and the inhibition effect of antivortex plate and diversion structure on liquid level fluctuation was studied.The results show that the liquid surface depression will be generated in the process of the large flow of liquid impacting the liquid surface,and if the liquid level is lower than the critical liquid level,gas will be entrained in the discharge liquid.Analysis of the influencing factors of the critical liquid level shows that setting the anti-vortex structure and weakening the liquid impact are the main optimization directions to reduce the critical liquid level.The use of diversion structure and anti-vortex plate structure can respectively weaken the liquid impact and suppress the liquid level fluctuation,and finally the critical liquid level height can be reduced to below 0.6 m.The research in this paper can provide guidance for the stable operation of the large flow drainage system of large cryogenic storage tanks.