微小口径涡街流量计设计与测量特性研究

Research on design and measurement characteristics of micro-bore vortex flowmeter

涡街流量计是基于流体振荡原理对流量进行测量的流量计,但在低流速下输出的信号很微弱,在实际测量过程中会叠加各种现场产生的噪音。并且目前工业上使用小口径涡街流量计在小流量工况下存在测量局限性,一般最小口径仅到DN15。针对目前涡街流量计存在的问题对DN10及以下的微小口径涡街流量计结构及参数进行研究,以满足工业上的测量新需求。基于模拟仿真计算平台,建立不同尺寸参数的微小口径涡街流量计数值计算模型并进行仿真计算,提出优化的涡街流量计结构尺寸。通过对不同压力监测点的压力波动强度及频率的研究,分析传感器的最佳布置位置。最后以电磁流量计为标准表对所研制的微小口径涡街流量计在微量程段进行了测试,对该被检流量计的误差、精度等参数进行实验,同时对雷诺数与斯特劳哈尔数之间的关系及仪表系数进行分析,结果表明,仿真所获的测量特性与实验测得的特性具有较好的一致性,且该微小口径涡街流量计相对误差优于0.5%,重复性等指标能够满足微量程段内的测量标准。

Vortex flowmeter is a flowmeter based on the principle of fluid oscillation to measure the flow rate,but the output signal at low flow rate is very weak,in the actual measurement process will superimpose a variety of on-site noise.At present,the small diameter vortex flowmeter used in industry has measurement limitations under small flow conditions,and the minimum diameter is generally only DN15.Aiming at the existing problems of vortex flowmeter,the structure and parameters of small diameter vortex flowmeter DN10 and below are studied,to meet the new measurement requirements in industry.Based on the simulation calculation platform,the numerical calculation model of the micro-diameter vortex flowmeter with different size parameters is established and the simulation calculation is carried out,and the optimized structure size of the vortex flowmeter is proposed.By studying the intensity and frequency of pressure fluctuation at different pressure monitoring points,the best position of sensor is analyzed.Finally,the electromagnetic flowmeter is used as the standard table to test the developed micro diameter vortex flowmeter in the micro range.The error and accuracy of the flowmeter are tested,and the relationship between Re and St and the instrument coefficient are analyzed.The results show that the measurement characteristics obtained by simulation are in good agreement with those measured by experiment.The relative error of the micro diameter vortex flowmeter is better than 0.5%,repeatability and other indicators can meet the measurement standards in the micro-range.