AN UNSTEADY-FLOW RATE MEASUREMENT METHOD UTILIZING DYNAMIC CHARACTERISTICS BETWEEN PRESSURE AND FLOW-RATE ALONG A PIPELINE (A METHOD USING PRESSURES AT 2 SEPARATED POINTS)

This paper describes an approach for estimating unsteady flow rate through oil hydraulic pipelines and components in real time. In this method, unsteady flow rate is estimated by using the hydraulic pipeline dynamics and the measured pressures at two distant locations along the pipeline. Unsteady flow rate in the time domain is obtained by convolutions between the weighting functions and the measured values of pressure. The weighting functions are obtained from the transfer functions by application of the inverse fast Fourier transform (IFFT). By scheming the high-speed operations of convolutions, data processing in a microcomputer is achieved in real time, using exclusive precalculated tables. Under unsteady laminar oil flow conditions, the good agreement between the estimated and measured flow rate waveforms illustrates the validity of the method proposed here.