【摘要】 科里奥利流量计依靠振动管检测流体流动.潜在的侵蚀或腐蚀会降低管壁厚度并影响其测量性能,严重情况下甚至可能导致结构完整性问题.由于管壁厚度直接影响其刚度,因此与刚度相关的诊断参数有助于识别潜在的测量和完整性问题.在假设的单自由度(SDOF)系统基础上,使用Matlab Simulink构建仿真模型,并使用双频驱动的方法计算刚度诊断参数;基于仿真结果,在数字信号处理(DSP)开发板中实现了控制回路及相关信号处理算法;使用正交解调算法并结合特殊设计的滤波器分离共振和非共振的响应信号,并实时计算振动管的刚度参数;为了设计实验,建立了振动管的有限元仿真模型,得到了刚度与力之间的关系;利用试验机对振动管施加轴向拉力和压力验证算法.实验结果表明:双频驱动的方法可以计算出振动管的刚度诊断参数,该方法可以为实际应用提供有用的诊断信息.更多还原

【Abstract】 Coriolis flowmeters rely on oscillating tubes to sense fluid flows.However,potential erosion or corrosion can reduce the tube wall thickness and affect their measurement performance,and severe thickness reduction may even result in structural integrity issues.As the tube thickness directly affects their stiffness,a diagnostic parameter related to stiffness will aid in identifying potential measurement and integrity issues.Under the assumption of a single-degree-of-freedom system,a simulation model was constructed in Matlab Simulink,and the calculation of a stiffness diagnostic parameter using the dual-frequency excitation method was simulated.On the basis of the simulation results,a control loop,along with relevant signal processing algorithms,was then implemented in a digital signal processing development board.A quadrature demodulation algorithm combined with specially designed filters was employed to separate resonant from non-resonant response signals,and the stiffness parameter of the oscillating tube was calculated in real time.To design the experiments,a finite element simulation model of the oscillating tube was established,and the relationship between stiffness and force was obtained.By employing a test machine,axial tension and compression forces were applied to the oscillating tube to verify the algorithms.The experimental results show that the dual-frequency excitation method can calculate the stiffness diagnostic parameter of the oscillating tube and can be used in real applications to provide useful diagnostic information.更多还原