带狭缝圆柱钝体流量测量特性研究

Study of Flowrate Measurement Characteristics of a Circular Cylinder with a Slit

涡街流量计的流量特性与旋涡发生体的形状和几何尺寸密切相关,提出了一种新型的带狭缝圆柱发生体结构并应用于涡街流量计。理论分析表明狭缝可以看作是一个反馈通道,可有效加快旋涡脱落并增强旋涡强度。在内径为50 mm的管道中进行实验,采集不同流量下带狭缝圆柱与梯形柱绕流产生的涡街信号,重点讨论带狭缝圆柱的小流量测量性能。实验表明,与梯形柱相比,带狭缝圆柱涡街信号更强,信噪比高,雷诺数测量范围可低至9.5×103,斯特劳哈尔数线性度更好。理论分析与实验结果表明,带狭缝圆柱具有较好的流量测量特性,可应用于涡街流量计。

The flowrate characteristics of vortex flowmeter is closely related to the size and geometry shape of vortex bluff body. A new kind of circular cylinder with a slit structure is proposed and applied to vortex flowmeter. Theoretical analysis shows that the slit can be regarded as a feedback channel, which can effectively accelerate vortex shedding and increase vortex intensity. Experiments were carried out in a water pipe with a diameter of 50 mm. Vortex signals produced by circular cylinder with a slit and trapezoidal cylinder respectively at different flowrate were collected. This paper mainly focuses on analyzing the low flowrate measurement performance of circular eylillder with a slit. Experimental results show that compared with trapezoidal cylinder circular cylinder with a slit possesses following characteristics ： vortex signal intensity is stronger, signal-to-noise ratio is higher, the Reynolds number of measurement range can be as low as 9.5 × 10^3 and linearity of Strouhal number is better as well. Theoretical analysis and experimental results manifest that circular cylinder with a slit possesses good flowrate meas- urement features and can be applied to vortex flowmeter successfully.