中文摘要：

针对中小口径超声波流量计的弯管二次流误差问题,运用数值仿真技术,分析了弯管二次流垂直误差与水平误差,由二次流流线规律推导出了二次流误差的计算公式。结合实际的流量计测量范围,设定雷诺数的变化范围为3 000~50 000,定量分析了安装在弯管下游5D、10D、20D位置的流量计在不同雷诺数下的误差规律。提出了＂用压力差来表现二次流强度,最终结合误差规律通过测量压力差来对弯管二次流误差进行修正＂的方法。研究结果表明,在雷诺数29 000之后,10D处的二次流垂直误差超过了5D处的误差,二次流垂直误差和水平误差的最大值分别约为1.2%和0.7%,经过仿真验证结果表明,该修正方法可行。

英文摘要：

Aiming at the bending pipe error of ultrasonic flowmeter proble,numerical simulation was carried out to study the secondary flow vertical error and horizontal error. The formula of secondary flow was derived from the secondary flow line. The simulation was run in different Reynolds number, Reynolds number ranged from 3 000 to 50 000. Ultrasonic flowmeters were installed at 5D, 10D and 20D distance to bending pipe downstream. A method was proposed that the pressure difference between the top of and the bottom of bending pipe outlet could be used to present the secondary flow intensity. Through the pressure difference the bending pipe error could be corrected. The results indicate that when Reynolds number is larger than 29 000, error at 10D exceed error at 5D. The maximum value of the secondary flow vertical error and the secondary horizontal error are about 1.2%and 0.7%respectively, correction method is proved to be right.