板翅式换热器不同入口方式的气液分配抗倾斜性能对比

Comparison of Tilt Resistances and Distribution in Entrances of Plate-fin Heat Exchangers under Tilt Angles

恶劣的海况环境引起的船体晃动倾斜会严重影响换热器内部流场的分布,降低换热器的换热效率,甚至会导致海上平台整个LNG流程停产等严重后果。通过CFD方法模拟研究板翅式换热器入口结构对单通道内的气液流场分布,研究了两种结构的("先混合、后分配"的传统封头结构,Model A;"先分配、后混合"的新型分配器结构;Model B)气液分配方式在倾斜条件下流量变化的规律。对比分析了不同倾角(3°、6°、9°和15°)作用下的两种结构的流量分配不均匀程度。研究结果发现:不同程度的倾斜,对结构内部流场的气液分配影响不同;倾角越大,气液分配均匀性所受影响越明显。在相同的倾斜条件下,Model B比Model A的流量变化率范围小,不均匀度标准方差变化范围也较小,Model B的抗倾斜性能更好,分配性能受倾斜影响小。综合结果表明,气液通过分配器"先分配、后混合"的方式(Model B)得到的流场分布能够更有效的抵抗倾斜条件带来的影响,该结构方式更适合在海上恶劣条件下工作。

Tilt motions could lead to flow maldistribution in plate-fin heat exchangers and cause safety problems in LNG processing. The gas-liquid distribution of the entrance structures in plate-fin heat exchangers is simulated.One structure is designed by the traditional method ＂mixing prior to distribution＂（ hereafter referred to as Model A）; the other structure is designed by the method ＂distribution prior to mixing＂（ hereafter referred to as Model B）. This study compared their gas-liquid distribution characteristics,and analyzed the differences of the flow changing rules under tilt conditions. The results shows that the range of βk,i,θin Model B is much more narrow when they encounter the same tilt angle,and STDmix,θ. in Model B is less than Model A,so the gas-liquid flow is distributed more uniformly in Model B,which structure has higher tilt resistance. The structure of Model B can decline the influence of tilt conditions to the flow distributions and work more effectively under the tilt condition.