To develop and investigate methods for the calibration of critical flow Venturi nozzles (CFVNs) and master meters to be used as primary calibration standards for gaseous hydrogen at high pressure (pmax = 100 MPa) and flow rates up to 10 kg/min. To enhance the methods available for air and inert gases (N2) to be used with hydrogen (e.g. gravimetric method). This includes a comparison of nozzle calibration results, and the determination and validation of uncertainty budgets.
To study CFVNs and perform dimensional characterisation. To develop and optimise an equation of state (EoS) for the foreseen pressure (100 MPa) range. To test toroidal and cylindrical CFVNs with different size and surface roughness, using alternative fluids up to 3.6 kg/min and to assess the feasibility of using alternative methods / fluids to perform hydrogen flow meter calibrations with CFVNs and to analyse nozzle behaviour (e.g. discharge coefficient) in comparison with the dependencies described in ISO 9300. To contribute amendments and restrictions, related to the use of nozzles with hydrogen, for possible inclusion in ISO 9300.
To evaluate the applicability of currently available models for nozzle flow and to develop a CFD model in OpenFOAM for high pressure (100 MPa) hydrogen flows through CFVNs., which takes relevant real gas effects into account. Furthermore, rough CFVN surfaces as well as non-adiabatic CFVN walls will be considered in this model.
To design and develop primary standards for use in the calibration of CFVNs and a rig for testing the suitability of master meters for use under medium pressure (i.e. p max = 3 MPa; Q N,max = 4 kg/h or about 100 kW fuel cell power) gaseous hydrogen flow conditions. To quantify the SI-traceable uncertainty of liquefied hydrogen flow measurement using alternative fluid calibrations under medium pressure conditions (i.e. vaporisation method: p max = 0.4 MPa, Q N,max = 4 kg/h; other methods: p max = 1 MPa, Q N,max = 5000 kg/h). To assess the performance of potential master meters, such as Coriolis flow meters, USM's and differential pressure devices, in the previously stated conditions. This project aims to improve the liquid hydrogen flow measurement uncertainty to 0.3 % - 0.8 %.
To facilitate the take up of the technology and measurement infrastructure developed in the project by
the measurement supply chain (calibration laboratories, NMIs, DIs), standards developing
organisations (ISO 9300, ISO 5167) and end users (hydrogen industry e.g. mobility, fuel cell, grid,
industry, storage and generation).
The project will be managed by the coordinator from PTB.