Instantaneous Liquid Flow Rate Measurement Utilizing the Dynamic Characteristics of Laminar Flow in Circular Pipes Available to Purchase

The instantaneous measurement of transient flow rates is an important problem in many fluid power applications such as the investigation of the flow ripple generated by hydraulic pumps or the measurement of flow rate changes at the ports of fast switching valves. This paper deals with the utilization of the dynamic characteristics of laminar flow in circular pipes for the indirect measurement of flow rates. A discrete time state space realization of the transmission line dynamics is computed via inverse Laplace transform and an identification and model reduction method based on the singular value decomposition. This dynamic system is used for the computation of the flow rate at one end of a pipe section. Special attention is paid to the identification of the speed of sound and the dimensionless dissipation number of the pipe section, since exact knowledge of these parameters is crucial for the reliabilty of the measurement results.