Impact on industrial and other user communities 

The results will considerably improve the availability of measurement systems and methods for the SI-traceable calibration of CFVNs and other flow meters in whole pressures up to 100 MPa. Traceable flow standards, in particular CFVNs, will be made available to accredited calibration laboratories, test rig companies and to the R&D departments of flow meter manufacturers. 

The implementation of the CFD code will be carried out in OpenFOAM so that every interested stakeholder can use it. The code will be made available together with a documentation of the include all essential parts, including tutorials for implementation. The CFD results will provide a complex spatial and temporal view of the flow field (which would otherwise be invisible for experimental investigation) and it can significantly contribute to the analysis and understanding of flow phenomena inside CFVNs (ISO 9300). An optimised CFD solver can also extend the set of experimental data for wide ranges of specific geometrical parameters and physical properties. In combination with other results from this project, a proper CFD model will lead to a ‘dry calibration’ of CFVNs. 

The experimental speed of sound data will provide the essential validation needed to assess the quality of the equation of state. This will facilitate an immediate reduction in the uncertainty of the CFVNs for metering high-pressure hydrogen flows and it will be of fundamental importance in hydrogen flow measurement science. 

Calibration laboratories and calibration rig construction companies currently rely on CFVN calibrations with air, natural gas, or other alternative fluids. This project will acquire the knowledge needed to assess the transferability of alternative fluid nozzle calibrations to the nozzles that are used with hydrogen and it will deliver primary standards for the direct calibration of nozzles with hydrogen. This will create impact by lowering the cost of recalibration. 

This project will provide two new calibration services for the calibration of liquefied hydrogen flow meters (Coriolis, ultrasonic meter, differential pressure) at pressures up to 1 MPa, and flow rates up to 5000 kg/h. These services will be able to be directly taken up by the instrument manufacturer stakeholders that are already linked to the project (several stakeholders/partners linked to the project), and by liquefied hydrogen trailer companies for which these flow rates are of interest. These services, and the availability of high-pressure CFVN hydrogen calibration, will be a cornerstone for verifiable measurements and for trustworthy trading in gaseous hydrogen. 

This project’s outcomes will be disseminated to calibration laboratories and industrial stakeholders, such as manufacturers of flow meters, by organising workshops and presenting the project’s results at conferences and in scientific journals. Workshops aimed at collaborators and stakeholders will be organised by the project. Knowledge will also be disseminated to end users through training courses and an advisory group, consisting of industrial stakeholders, will be established and will meet regularly to exchange information with the consortium and to ensure that the project is delivering relevant outputs and information for end users. The participation of industrial partners in the project will also help to align the project with industrial needs. 

Impact on the metrology and scientific communities 

Methods will be set up for the metrological analysis of measurement systems for very high pressure gaseous and liquified hydrogen. Based on these outputs from the project, NMIs/DIs will be able to establish new capabilities and new knowledge at their institutions for use in calibrations. Calibration data will be generated for a range of nozzles and this will contribute to research on nozzle flow physics, in particular for very high Reynolds numbers as the measurement will be performed in a new pressure range. Also NMIs/DIs will be better able to understand the behaviour of CFVNs with hydrogen at high(est) pressure, and this will create impact by providing input on the most important uncertainty contributions, which will be used to reduce the calibration uncertainty. Based on the project’s results, a recommended mise en pratique for assuring traceability in the range up to 100 MPa using CFVNs will be derived. This will benefit calibration laboratories as they will be able to uptake a verified method for traceable high-pressure hydrogen calibration. 

Calibration with alternative fluids will also create impact for calibration laboratories as they will be able to use these methods to establish calibration and traceability for hydrogen with their existing infrastructure. The metrological and scientific community will benefit as they will gain a new opportunity for cross correlation to the high-pressure region and they will be able to establish new traceability and uncertainty calculation methods. 

Fundamental scientific knowledge about nozzle hydrogen flow physics will be gained, comprising a better understanding of the impact of the Joule-Thomson effect as well as the pressure and temperature dependency of the isentropic exponent. The development of a CFD modelling approach will improve simulation results by including real gas effects. The results will initiate further scientific activities, and these will strongly contribute to hydrogen flow measurement science. 

The availability of a validated equation of state for hydrogen, based on experimental data with a traceable uncertainty assessment, will enable the traceable conversion from mass to volume using a well-defined, high-accuracy density. This will lead to a smaller overall flow measurement uncertainty. Fundamental equation of state work will be performed on the conversion of parahydrogen to normal (ortho) hydrogen. High-pressure speed of sound measurements will be performed in an unknown region of density and the speed of sound data will be combined with the fundamental para hydrogen to normal (ortho) hydrogen work. This has the potential to lead to highly cited publications. 

A robust infrastructure for the calibration of CFVNs with hydrogen (Qmax = 4 kg/h), will be provided by the development of primary standards and the performance of an intercomparison. Meter types, which are suitable for the measurement of hydrogen gas flow, and their (dis)advantages in this application, will be identified.  

The flow measurement uncertainty of liquified hydrogen is currently unknown/unquantified, but it is estimated to be 1 % to 2 %. This project’s activities in liquefied hydrogen flow measurement will contribute to reducing this measurement uncertainty (target 0.3 % to 0.8 %). SI-traceable liquefied hydrogen flow measurement methods and/or standards will result from this project (1000 kg/h – 5000 kg/h flow rates, and p_max = 1 MPa). 

Impact on relevant standards 

This experienced consortium will provide input to several national and international committees dealing with hydrogen in general and with hydrogen flow metering in particular. Several partners already have strong links with the relevant committees (ISO, OIML, CEN, WELMEC) and working groups. Significant early stage input is anticipated to working group ISO/TC30 related to ISO 9300 (Measurement of gas flow by means of CFVN), ISO 10790 (Measurement of fluid flow in closed conduits - Guidance to the selection, installation and use of Coriolis flowmeters (mass flow, density, and volume flow measurements)) and ISO 5167 (Measurement of fluid flow by means of differential pressure devices). Hydrogen gas flow calibration data will be provided to be considered for use in updating the ISO 9300 standard. Furthermore, the project’s results will boost improvements in liquefied hydrogen flow measurement techniques that can either be used as possible input to update ISO 21903:2020 or as starting point for a new work item on liquefied hydrogen flow metering, addressing the calibration and installation requirements under ISO/TC 28. 

Longer-term economic, social, and environmental impacts 

The hydrogen strategy for a climate-neutral Europe is a pillar of the European Green Deal. It offers a solution to decarbonise industrial processes and economic sectors where reducing carbon emissions is both urgent and hard to achieve. In the longer term, this project will establish the necessary metrological infrastructure to decarbonise automotive and industrial sectors through hydrogen, and to enable the large-scale transport of energy in the form of liquefied hydrogen. 

The efficiency of products and processes can be improved by providing reliable flow and quantity measurements. For some applications, hydrogen may lead to CO₂-free processes, e.g. the replacement of coke by hydrogen in steel production. The process control and the acceptance of hydrogen as an alternative fuel will be improved by reducing the uncertainties of the measurement devices.  

As hydrogen fuel cell vehicles only emit water vapour, the exhaust gas is fully safe from a health perspective. However, conventional petrol and diesel engines can produce harmful levels of carbon monoxide, nitrogen oxides and particles, and in addition large amounts of carbon dioxide. In the longer term, this project will support the acceptance of hydrogen vehicles by the market, allowing consumers to opt for a vehicle that produces safe levels of emissions. 

Just like electricity, hydrogen is an energy vector which can only be produced from other sources of energy like wind, solar radiation, biogas, or fossil fuels. It can be stored relatively easily in a gaseous and liquified state, the latter one permitting a very high energy density which makes it very interesting for the transport sector. For some applications like steel production, gaseous hydrogen can be used directly as a process gas. During the development of a hydrogen-based economy, fossil fuels may be used in parallel which will allow a smooth reduction in fossil energy usage. The market launch of hydrogen has been fast. There are several strategies for hydrogen use, which each need to be investigated for their overall efficiency. An enduring evaluation requires an accurate determination of hydrogen quantities and flow rates, which this project will help to provide.