Hydrogen is an environmentally cleaner source of energy,
particularly in transportation applications,
without release of pollutants or greenhouse gases.
The problem with using hydrogen as a fuel is the storage.
Compared to natural gas, hydrogen has smaller energy content
per mole. This implies that hydrogen should be stored at
higher pressures in comparison to natural gas so that a
reasonable amount of fuel in the vehicle is reserved.
For safety issues, it is important to determine how the gas
is released in the case of failure.

Hydrogen release from a high-pressure chamber (up to 700
bar), formation of underexpanded supersonic jet and eventual
impingement of the jet onto a surface located at a certain
distance from the nozzle is to be modelled in this paper.
Different Equations Of State (EOS), such as Ideal-Gas,
Abel-Noble, Redlich-Kwong and Beattie-Bridgeman, are
considered for highly compressed gas inside the chamber and
a mathematical model is developed to calculate the release
of hydrogen by applying conservations of mass and energy to
the control volume containing the gas inside the chamber.
The variables at the nozzle obtained using different EOS
are taken as boundary conditions for the compressible
solver, and their effect is assessed in terms of Mach disk
location and the level of the pressure load at the
stagnation area on the surface. It is shown that
pressure signals have highly oscillatory behaviour,
therefore certain techniques should
be used in order to observe certain difference
between the results corresponding to real- and ideal-gas EOS.