Instantaneous flowrate measurements in high-pressure liquid flows

A new flowmeter suitable for high-pressure flows and with a prompt dynamic response is presented. It is constituted by two pressure transducers installed on the monitored high-pressure pipe at a fixed distance one from the other, together with a low-pressure flowmeter that provides a time-averaged flowrate. The measurement algorithm consists of an ordinary differential equation obtained by combining the mass conservation partial differential equation and the momentum balance one applied to the considered piece of pipe comprised between the two pressure transducers. Due to the absence of a master instrument that can be employed as reference to verify the consistency of the measured flowrate, the flowmeter accuracy has been demonstrated by means of numerical models of various hydraulic components, rigorously validated through pressure measurements. The flow ripple of gear pumps has been measured, as well as the flowrate entering a Common Rail injector. For all these cases, the measured flowrate and the one obtained by means of the numerical model are in very good agreement, leading to a robust validation of the presented measurement device.