With the stringent emission regulations and renewable energy concerns, hydrogen application either to direct injection combustion or fuel cell application attracts more attention. However, a major obstacle for vehicle utilization of hydrogen as a main fuel is onboard storage. Due to the low mass density, hydrogen has the lowest energy per unit volume among all potential fuels. One of the typical methods to store hydrogen is in very high pressure storage tanks. The high pressure (35 MPa and higher) combined with small size of hydrogen molecules makes the tanks and adjacent fittings prone to leakage, which may cause important potential safety issues, given the wide combustion range and easy ignition of hydrogen.Our research focuses on characterizing the relative importance of basic modes of hydrogen leakage at the joints of commercial stainless steel fittings. Two types of fittings that include National Pipe Thread Standard (NPT) screw treads and standard compression fitting ferrules are modeled as a capillary duct with the same hydraulic diameter (height of the duct). The flow rate through the contacting faces is determined and correlated to the differential pressure drop, thread treatment, torque, and temperature. The analytical models from the viscous flow regime to free-molecular flow regime are derived. We compare the analytical formulation in the slip flow regime with previous experimental results for nitrogen and helium, and then apply this analytical model to predict the hydrogen leakage at the high pressure ratio condition. An experiment extending these results to hydrogen is also reported in the paper, and the results are compared with the analytical prediction.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Analysis and Test of Compressed Hydrogen Interface Leakage by Commercial Stainless Steel (NPT) Fittings


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2006 World Congress & Exhibition ; 2006



    Publication date :

    2006-04-03




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Analysis and test of compressed hydrogen interface leakage by commercial stainless steel ( NPT ) fittings

    Ge,X. / Sutton,W.H. / Univ.of Alabama,US | Automotive engineering | 2006


    2006-01-0130 Analysis and Test of Compressed Hydrogen Interface Leakage by Commercial Stainless Steel (NPT) Fittings

    Ge, X. / Sutton, W. H. / Society of Automotive Engineers | British Library Conference Proceedings | 2006



    Fittings for compressed gas storage vessels

    WEXLER JASON STEIN / MORRIS KEVIN KAI / SHILLING JAMIE MARIE-LOBUE | European Patent Office | 2020

    Free access

    FITTINGS FOR COMPRESSED GAS STORAGE VESSELS

    WEXLER JASON STEIN / MORRIS KEVIN KAI / LOBUE JAMIE MARIE | European Patent Office | 2018

    Free access