锥形流量计下游支撑及取压位置的试验研究

Experimental Research on Downstream Strut and Pressure Tapping Location of Cone DP Flow Meters

锥形流量计应用广泛,其国际标准正在起草中。锥形流量计发展过程遇到两个问题:安全性和制造一致性差,具有双支撑结构的锥形流量计可解决此问题。为保证增加的双支撑结构不会影响锥形流量计的测量性能和较短的表体长度,需要研究下游支撑和下游取压位置。根据锥形流量计尾流流场的速度分布和压力分布的状况设计相关的改进试验,选择合适的下游支撑和下游取压位置。试验使用的锥形流量计经过特殊设计:锥体、下游支撑位置、下游取压位置都可以按照要求变换位置。试验得到适用于不同直径管道的下游取压位置和支撑位置的选取规律。不同管径和等效直径比下的锥形流量计试验数据显示:改进后的双支撑形式的锥形流量计样机比悬臂梁锥形流量计具有更好的流出系数不确定度。

Cone flow meter is applied extensively and the international standard for cone flow meter is being drafted. There are two problems in developing of cone flow meters： Poor machined identity and safety performance. The problems can be solved by a cone flow meter with dual support struts. The position of the low pressure tapping and the downstream strut should be studied to ensure the cone flow meters with good measurement performance and short tube. A series of optimization experiment choosing the appropriate downstream support position and low pressure tapping location have been designed according to the velocity and pressure distribution of cone flow meter wake flow. The cone flow meters with special design-the cone, the downstream support position, the low pressure tapping position can be transformed in accordance with requirements-have been used in process of experiment. A method to choose the low pressure tapping position and downstream strut location of different diameter cone flow meters has been found. The cone flow meters with dual support struts optimized by the method have been verified with good measurement performance after experimental validation.