Assessment of Dynamic Properties of Variable Area Flowmeters

In previous works, a non-linear equation describing variable area (VA) flowmeters in transient was presented. The use of a full nonlinear equation, despite giving accurate results, can be difficult and time-consuming and it requires having specific software and knowledge at one’s disposal. The goal of this paper was to simplify the existing model so that it could be used in applications where ease of use and ease of implementation are more important than accuracy. The existing model was linearized and simple formulae describing natural frequency and damping coefficients were derived. With these parameters, it is possible to assess the dynamic properties of a variable area flowmeter. The step response form can be identified and natural frequency and settling time can be estimated. The linearized model and the experiment were in reasonable agreement. The step response type was captured correctly for each of the six VA meter types. The error in the undamped natural frequency was not larger than 15%, which means that the VA meter sensor’s dynamic properties can be predicted at the design stage with sufficient precision.