Development and assessment of a new operating principle for the measurement of unsteady flow rates in high-pressure pipelines

Instantaneous mass flow rate measurements in high-pressure transmission pipelines under transient flow conditions can be valuable for the analysis of hydraulic power systems. However, at present no reliable commercial measuring device is available for pressure levels beyond 300 bar. A new operating principle, of general application, for measuring the flow rate in high pressure flows (from 300 to 2000 bar) was developed and assessed. The innovative device was capable of accurately evaluating the instantaneous mass flow rate on the basis of the pressure time-histories detected at two different locations by high pressure transducers. The measurement operating principle was detailed and technical indications for the flowmeter correct design were provided. For validation purposes, the flow rate measurements taken at the inlet of a Multijet Common Rail (CR) injector were compared to the theoretical data predicted by an ad-vanced numerical model of the complete fuel injection system. The developed flowmeter was then applied to characterize the flow rate ripple at the delivery of the CR high-pressure reciprocating pump.