Improvements of Functions in a Cylindrical-Choke-Type Instantaneous Flowmeter

Abstract

Instantaneous flowmeters are indispensable to analyze dynamic behavior of pipelines and hydraulic systems. Therefore, it is very important theme to establish the method to measure accurately and easily unsteady flowrate of liquid through pipelines and hydraulic systems in real time. Recently we developed a simple instantaneous flowrate sensor making use of cylindrical chokes. In this system, the dynamic relationship between the pressure drop across the choke and the flowrate through the choke is utilized and calculated by a micro computer system. The numerical operation in real time is performed by newly devised exclusive hardware circuits, in which sampling period is set at 78μs. In this report, we proposed a new improved method to provide some advantages on the numerical operation for the instantaneous flowrate measuring system. Introducing tables on memories (RAM) which are set in advance and applying Runge Kutta method give following advantages: unnecessity of another expensive hardware circuits, improvements of accuracy in high frequency region and capability of correspondence to system parameter changes.