抗振动涡街流量仪表的研究与设计

Vortex flowmeter is a kind of fluid vibration flowmeter. The external vibration noise has always been an important factor affecting the precise measurement of the vortex flowmeter. This project aims to improve the anti-vibration performance of vortex flowmeter. The innovative work for the vortex flowmeter in the design and testing of key theory and technology is listed as followed. The core components of the vortex flowmeter are sensors and converters. On one hand, the structure of the sensor is intensive studied, and the structure parameters of vortex sensor are optimized by analytical methods of multi-physics coupling to reduce the noise signal and improve the quality of vortex signal. On the other hand, the amplitude-frequency characteristic of 1/f^2 is deduced based on the principle of momentum consistency of vortex signal. According to the amplitude-frequency characteristics between the vortex signal and the vibration noise, the digital filtering algorithm of momentum tracking performance is designed. In this project, the complete vortex flowmeter system will be built and the prototype will be made. Then, the performance of the vortex flowmeter will be tested, including accuracy, range ratio and so on. According to the design of the anti-vibration test scheme, the anti-vibration performance will be tested and vibration test indicators of vortex flowmeter will be proposed innovatively.

涡街流量计是流体振动型仪表，外界振动噪声一直是阻碍仪表精确测量的一个重要原因。本项目以提高涡街流量仪表的抗振动性能为研究目标，在其设计与测试的关键理论与技术上进行以下创新工作：涡街流量仪表的核心部件是传感器和转换器，一方面通过对传感器结构的深入研究，从多物理场耦合的分析计算角度对涡街传感器结构参数进行优化，减少噪声信号进入传感器并获得高质量的涡街信号；另一方面，根据涡街信号动量一致性原理，分析其1/f^2的幅频特性与振动噪声之间存在的统计规律，设计具有动量跟踪性能的数字滤波算法。进而搭建具有抗振动性能的涡街流量计样机，对仪表的精度和量程比等性能进行综合测试，设计抗振动测试方案并在国内首创性地提出涡街流量仪表的振动测试指标。

涡街流量计具有量程范围大、测量精度高、测量的稳定性及可靠性好等优点，因而被普遍应用于流体计量检测。但由于涡街流量计在本质上属于流体振动型流量计，测量过程易受噪声干扰的影响。尽管滤波器组频谱分析法已使涡街流量计在抗干扰能力上得到了充分的提升，但其还存在频带内噪声滤除的问题，这也是滤波器组频谱分析法应用在实际中的关键。本项目研究了滤波器组频谱分析法的原理与特点，在滤波器组频谱分析法的基本框架下，依据涡街信号的集中趋势特性，提出了一种集中趋势综合分析方法。通过理论分析和仿真实验验证该方法表征了涡街信号的集中趋势特征，具有众数特性且能适应各种干扰情况下产生的非对称数据分布，同时解决了滤波器组频谱分析法的频带内噪声滤除问题。另外，根据涡街信号动量一致性原理，分析其1/f^2的幅频特性与振动噪声之间存在的统计规律，设计具有动量跟踪性能的数字滤波算法。最后，在浙江迪元仪表有限公司和实验室分别完成了实流标定实验和实流抗干扰实验。实验结果表明，本项目的信号处理系统具有较高的测量精度和抗干扰性，能够较好地克服瞬态冲击振动干扰的影响，可以满足涡街信号的频率测量和滤波要求。