Abstract
A new approach using finite element method to deriving a fluid line dynamical model for fully-developed laminar flow in a duct with arbitrary shape, is presented. This approach makes it possible to apply the model-based method proposed for measuring instantaneous flow rate in a circular pipe to more general and practical cases of flow measurement.
Initially, we give a general discussion on the deriving of the finite elements fluid line model. The fluid line model is represented by the form of a state variable equation and can be easily implemented on a computer to estimate duct flow velocity profiles.
Next, we show that the model has higher accuracy than an analytical model when they have the same order, by comparing it with truncated analytical fluid line models for circular and rectangular ducts in frequency domain.
The relation between the dynamic accuracy and the system structure of the model, that is, the model order and its eigenvalue distribution, is explained by taking the case of a circular pipe as an example.
