Abstract: Multi-orifice plate, as a throttle element, has various advantages in the flow rectification, low noises, low pressure loss and stable pressure drop for flux measurements. However, the prediction method of pressure drop characteristics of multi-orifice plates is still unclear so far. This paper performed an experimental study on the pressure drop characteristic of multi-orifice plates using city water as the fluid. Five orifice plates with the hole number from 172 to 744 and the equivalent diameter ratio of hole's to pipe's from 0.544 to 0.666 were tested in the Reynolds number from 4×10⁴ to 1.6×10⁵. The results showed that compared with the single orifice plate under the same equivalent diameter ratio and flow conditions, the viscous dissipation caused by the eddy current behind plates was small, resulting in the lower pressure loss coefficient for multi-orifice plates. Using the calculation method for the standard single orifice plate to predict the pressure loss coefficient of multi-orifice plates with a corrected parameter of the equivalent diameter ratio, which was recommended by the Chinese standard HG/T 20570.15-95, would lead to a marked overestimate. Therefore, such a simple method was not suitable for multi-orifice plates. The predicted results of the pressure loss coefficient with the Holt correlation were in good agreement with the experimental results, indicating that it was suitable to take both the equivalent diameter ratio and relative thickness into consideration in the correlation. It was suggested to study further in this regard for reaching a satisfied methodology of pressure drop prediction for multi-orifice plates.

Key words: multi-orifice plate, pressure loss coefficient, throttling, flow, fluid mechanics, hydrodynamics

摘要： 多孔板作为节流元件具有整流、低噪声、低压损及压差更稳定等优点，然而多孔板压降特性的预测方法目前仍不清晰。以常温水为实验介质，在Re数为4×10⁴~1.6×10⁵范围内，对孔数为172~744、等效直径比为0.544~0.666的多孔板进行了压降特性实验研究，并将实验结果与文献中相关的关联式预测结果进行了比较。结果表明：在相同开孔直径比和流动条件下与单孔板相比，多孔板后涡流引起的黏性耗散较小，因而其压损系数明显低于单孔板；计算多孔板压损系数时，若采用等面积折算所得等效直径比按单孔板进行计算，会使得预测结果明显偏大；Holt关联式的压损系数预测结果与实验结果最为相符，表明同时考虑开孔直径比和孔板相对厚度影响的压损系数关联式预测精度较优。建议通过进一步研究建立完善的多孔板压降预测方法。

关键词: 多孔板, 压损系数, 节流, 流动, 流体力学, 流体动力学