液舱旋转射流惰化模拟及优化

Inerting Simulation and Optimization of Swirling Jet in Tank

为探究气体惰化机理,提高惰化过程效率,对卧式椭球状LNG液舱的气体惰化过程进行数值模拟与优化。采用从椭球状液舱端部直流射流、旋转射流和混合射流的进气方式,分析气体射流流场结构和惰化效果,探究不同进气方式对惰化过程影响的机理,并提炼其惰化优化方案。结果表明:在进气流量一定时,旋转射流的惰化效果优于直流射流和混合射流,这是由于旋转射流会产生更大的进气扩张角,可大幅减少惰化死角的存在,有利于在储罐内部形成推移式惰化;旋转射流相对直流射流可节省40.4%氮气量和惰化时间,相对混合射流可节省26.2%氮气量和惰化时间。旋转射流优化方案可减少氮气耗量并节省惰化时间,提高惰化过程效率,具有较高的经济性,对于实际LNG液舱的气体惰化过程具有重要指导意义。

In order to explore the gas inerting mechanism and improve the inerting process efficiency,the numerical simulation and optimization of gas inerting process in the horizontal ellipsoid LNG tank is performed.With the gas inlet modes of direct-current jet,swirling jet and mixed jet at the end of the ellipsoid tank,the flow field structure and inerting effect of gas jet are analyzed,the influence mechanism of different gas inlet modes on the inerting process is explored,and their inerting optimization schemes are refined.The results show that:the inerting effect of swirling jet is better than that of direct-current jet and mixed jet when the gas inlet flow is fixed,this is because the swirling jet generates a larger gas inlet divergence angle,which can greatly reduce the presence of inerting dead angle,and is conducive to forming the displacive inerting inside the tank;compared with the direct-current jet,the swirling jet can save 40.4% nitrogen and inerting time,while compared with the mixed jet,the swirling jet can save 26.2% nitrogen and inerting time.The swirling jet optimization scheme can reduce the nitrogen consumption,save the inerting time,improve the inerting process efficiency,possess the higher economy,and be of important guiding significance for the gas inerting process of actual LNG tank.