The fueling of hydrogen vehicles in three minutes enabling
ranges above 500 km offers a significant advantage over other types
of electric powertrain vehicles. SAE J2601, published in 2010,
offers the first and only worldwide guideline to standardize
fueling methodology. Due to the properties of hydrogen and
compressed storage, each type and geometry tank heats up
differently. Therefore, a hydrogen fueling methodology needs to
take into account the range of storage anticipated from all
automakers. This paper will describe a simulation tool developed in
order to be able to assist in the development of a fueling
procedure for General Motors Company; SAE J2601 team and the
validation thereof.
A reduced numerical simulation model has been developed that
simulates the thermal response of a compressed gas storage tank
operated under transient conditions. The stored gas is represented
as a lumped mass with a spatially uniform temperature and pressure
distribution inside the cylinder; a real gas model is employed to
calculate the gas properties. The heat transfer through the
cylinder wall is modeled by one-dimensional heat conduction in
radial direction. The heat transfer coefficient from stored gas to
the inner cylinder wall was provided by detailed three-dimensional
transient computational fluid dynamics (CFD) simulations. These CFD
simulations resolved all solid material layers as well the gas
volume utilizing a real gas model. An instrumented tank with
thermocouples inside both gas and cylinder walls was built and
tested over a wide range of operating conditions to evaluate the
quality of the simulation results. The test series included
refueling and defueling at hydrogen gas flow rates ranging from 0.5
to 30 g/s at ambient temperatures from -40 to +40°C. The reduced
simulation model predicts the average gas temperature evolution
during refueling to an accuracy of approximately 1°C.