大型绕管式换热器气液均布器流体分配特性试验研究

Experimental study on fluid distribution characteristics of gas-liquid distributor in large wound tube heat exchanger

针对LNG/FLNG大型绕管式换热器壳侧空间气液两相流体不均匀性造成的换热性能衰减问题,提出了一种适用于大型绕管式换热器的环管式均布器,并设计搭建了均布特性研究试验平台,研究不同流动条件下,沿径向、周向每个通道流量的比例系数和离散系数,并对有无均布器条件下的流体分配情况进行了对比。结果表明,流体分布随着流量增大而更加均匀,气相分布均匀性优于液相,气液两相周向分布均匀,径向分布由内至外两相质量流量逐渐减少,最内圈流量约为外圈流量的1.2倍,两相体积流量由内至外有所增大,最外圈流量约为内圈流量的1.5倍;放置均布器后,两相体积流量离散系数最大可以减小64%,两相质量流量离散系数最大可以减小57%。研究成果可为LNG/FLNG大型绕管式换热器均布器结构设计提供参考,有利于进一步提高均布效果。

The uniformity of gas-liquid two-phase fluid and the flow distribution relationship in the shell side space of LNG/FLNG large-scale wound tube heat exchanger directly affect its heat transfer performance.To solve this problem,a ring tube distributor suitable for large-scale wound tube heat exchanger was proposed,and an experimental platform for studying the uniformity characteristics was designed and built to study the proportion coefficient and dispersion coefficient of flow in each channel in radial and circumferential directions under different flow conditions,and the fluid distribution under the condition without distributor was compared.The results show that the fluid distribution is more uniform with the increase of flow rate,the uniformity of gas phase distribution is better than that of liquid phase,the circumferential distribution is uniform,the radial distribution decreases from inner to outer two-phase mass flow,the flow rate of the innermost ring is about 1.2 times of that of the outer ring,the volume flow rate of the two phases increases from the inside to the outside,and the flow rate of the outermost ring is about 1.5 times of that of the inner ring.After placing the distributor,the two-phase volume flow dispersion coefficient can be reduced by 64%and the two-phase mass flow dispersion coefficient can be reduced by 57%.The research results can provide a reference for the structural design of the distributor of LNG/FNG large wound tube heat exchangers in order to further improve the uniformity effect.