An Approach to Extend the Potential of the Remote Measurement Method for Unsteady Flow Rate using Hydraulic Pipeline Dynamics : 2nd Report, On an Extrapolation Method

Abstract

The paper describes an approach for extending the potential to estimate unsteady flow rate though oil hydraulic pipelines and components in real time. In this method unsteady flow rate at an arbitrary point along the pipeline is estimated by using the hydraulic pipeline dynamics and the only measured pressure values at two distant points along the pipeline in high responsiveness. This method has some advantages, that is, more easy and convenient to install without flow disturbance and with high responsiveness to unsteady flow rate changes. There are two minor methods, an interpolation method and an extrapolation method. This paper mainly describes the extrapolation method. In the extrapolation method, unsteady flow rate at the arbitrary external portions between two pressure measuring points is obtained by an inverse Fourier fast transform between the weighting functions and the measured pressure values. And this method is considered to be most useful for practical purpose. Under unsteady laminar oil flow conditions, the good agreement between the estimated and directly measured flow rate waveforms illustrates the validity of the method proposed here. In addition, a real time flow monitor applying this method is proposed and the validity is ascertained.