并联管组流量分配特性研究

Study on Flow-rate Distribution Characteristics of Parallel Pipes

并联管组主要由分流集箱、汇流集箱和多个并联支管构成,与单一管路相比,其结构更加复杂,流体在集箱内的流动情况以及各支管中的流量分配受到多种因素的影响。流体流量分配存在不均匀性,这给并联管组的换热特性等造成不利影响,甚至给工业生产带来安全隐患。利用Fluent软件模拟流体在并联管组内的流体力学特性,探索了入口方式、流体流速、集箱及支管规格等因素对并联管组流量分配不均匀性的影响,得到流体以径向方式流入、增大集箱直径和减小支管直径或通过降低流体入口流速的方式均可提高流体分配均匀性的结论,并提出通过增大集箱的直径以减小流体流速;增加支管的长度、减小支管直径,或在某些板加节流孔板或隔板以增大支管内摩擦阻力改善流量分配不均匀性等措施,以提高相关设备运行的经济性和安全性。该研究结果对于实际生产中并联管组的优化提供指导意见。

The parallel pipe group is mainly composed of distributing header, collecting header and several parallel pipes. Compared with a single pipe, the structure of the parallel pipe group is more complex. The flow situation of fluid in the collecting header and the flow-rate distribution of branch pipes are affected by many factors. The non-uniformity of the flow-rate distribution has an adverse impact on the heat transfer characteristics of parallel pipe group, and even brings potential safety hazards to industrial production. The mechanical characteristics of fluid in parallel pipe group are simulated by FLUENT software, and the effects of inlet mode, fluid velocity,the size of collecting header and parallel pipes on the flow-rate distribution non-uniformity of parallel pipe group are discussed. The results show that the flow-rate distribution uniformity can be improved by radial inflow, increasing the diameter of the collecting header,reducing the diameter of the branch pipes or reducing the fluid inlet velocity. It is proposed to increase the diameter of the collecting header to reduce the fluid velocity, increase the length of branch pipes and reduce the diameter of branch pipes, or add orifice plate or diaphragm on some plates to increase the friction resistance in the branch pipes, so as to improve the non-uniformity of flow distribution and improve the economy and safety of relevant equipment operation. The research results can provide guidance for the optimization of parallel pipe group in practical production.