Numerical simulation on sonic nozzle up to 5 MPA covering hydrogen and air to support potential traceability chain

Coriolis flow meter was the mainly flow meter used in the hydrogen dispenser related to the trade of hydrogen refueling station. To be satisfied with the requirement of OIML R139, the potential traceability chain with expected uncertainty was presented for Coriolis flow meter, in which sonic nozzle was treated as master meter and traceable to the pVTt facility in NIM with air. To achieve the expected uncertainty for the potential traceability chain, numerical simulation for sonic nozzle was conducted within the Reynolds number (1.03 × 10 4 ∼1.12 × 10 6 ) up to 5 MPa with hydrogen and air. The preliminary results showed that the additional uncertainty resulted from working fluid change was less than 0.23 % within the capability of the pVTt gas flow standard facility in NIM with air, which supported the expected uncertainty 0.35 % for hydrogen traceable from 0.20 % for air in the potential traceability chain.