复杂通道内流体压降与流量分配特性研究

Research on the Distributions of Differential Pressure and Mass Flowrate of Fluid in Complex Pipeline System

以中原乙烯公司运行的由意大利CTIP公司提供的换热器水进口复杂通道为例,对多通道、多分支系统进行了初步研究,建立了一维数学模型,用数值求解得出流动分布情况.进一步用数值方法求出两平行平板间流体绕流圆柱形障碍物时沿圆柱周向的速度分布和压力分布,并同实际的炉管失效情况进行了比较.结果表明:各管道中接近入口端支路中的流量分别是远端支路中流量的2倍以上;压力较低的区域集中在滞止点后圆心角θ为60°～120°和-60°～-120°范围内的管壁附近,此区域压力低,可使该区域流体沿环缝轴向分流的流速减小,造成环缝内的轴向速度沿管周向分布不均匀,这是炉管失效的主要因素之一.

A one dimensional mathematic model for profile of flow rate distribution is presented and the description of the profile in the complex flow system is obtained. The profile in the model of two parallel plates with columns between them is obtained by dynamic numerical method. Analysis is carried out by comparing the calculated profile along the perimeter of the column with the failure of tubes in practice. The conclusions are as follows: The flux in the subpipeline close to channel inlet is more than two times of the flux in the one close to channel outlet. The area with lower pressure locates mainly at the range from 60～120 degrees and -60～-120 degrees. The lower pressure in the above area decreases the velocity in the direction of tube axis and results in a nonuniformity profile in interspace along the direction of circumference. And the nonuniformity distributions of pressure in the direction of circumference and the distributions of velocity in the direction of tube axis are among primary factors resulting in tube invalidation.