基于外差式随机共振的涡街频率检测方法

A Method Based on Heterodyne Stochastic Resonance to Detect Vortex Shedding Frequency

涡街频率检测是涡街流量计的关键技术问题,也是当前的研究热点。分析非线性双稳系统在噪声和单一频率信号、多频率信号作用下的随机共振特性,将外差式频谱分析与随机共振原理相结合,提出基于外差式随机共振的涡街频率检测方法。理论分析、数值仿真和试验结果表明,含噪的涡街信号通过随机共振能有效地提高涡街信号信噪比,准确获取涡街频率。该方法在涡街频率检测中的应用是可行和有效的,为提高涡街流量计现场适应性及小流量弱涡街信号频率检测提供了一种新的方法。

The detection of vortex shedding frequency is a key technical problem of vortex flowmeter, and also a main subject of present research. The stochastic resonance characteristics of non-linear bistable system under the noise, single frequency and multi frequencies action are analyzed. With the combination of heterodyne power spectrum and stochastic resonance, a method based on heterodyne stochastic resonance to detect vortex shedding frequency is proposed. The theoretical analysis, numerical simulation and experimental results manifest that the SNR of vortex signal can be improved effectively and the vortex shedding frequency can be obtained accurately with the stochastic resonance applied to vortex signal. The method is feasible and effective in the detection of vortex shedding frequency. It is also a new method to improve the adaptability of vortex flowmeter in practical application and measure the low and weak vortex signal frequency accurately.