Excitation of Piezoelectrically Actuated Nozzle-Flapper Valve and Its Potential for Fuel Flowmeter Dynamic Calibration

In this article, a piezoelectrically actuated flow excitation approach is presented for producing short rise time flow rate changes. This is a crucial requirement from flowmeter dynamic calibration. A single nozzle-flapper valve (NFV) is adopted as excitation flow generator. A commercially available piezo stack drives the flapper. Time-domain comparison between pressure difference across the reference restrictor and the indicated value of tested flowmeters in the circuit is made for the current dynamic performance of the tested flowmeter. Computational fluid dynamics (CFD) simulation is implemented for the pipeline system to investigate the excitation characteristics based on the dynamic pressure distribution. The experimental device is designed, using a turbine flowmeter in a fuel pipeline. The excitation experiments are conducted, with varying voltages applied to the piezo stack and fuel supply pressure. The experimental dynamic pressure in the control chamber agrees well with that obtained by CFD simulation. And the pressure gain on null position of the single NFV is slightly smaller than the theoretical value, whose correction factor is derived. This article demonstrates that a piezoelectrically actuated NFV can be effectively used in generating short rise time flow rate changes under different operating conditions, avoiding disturbance to the upstream flow field of the tested flowmeters. The flow excitation device is applicable to flowmeter dynamic calibration.