Dispersion of hydrogen release in a naturally ventilated covered car park

Abstract

Highlights Hydrogen release from onboard storage in a covered car park is numerically investigated  Release and dispersions from a range of TPRD diameters is simulated  A 0.5 mm diameter TPRD was found to be inherently safer for 700 bar storage  The angle of TPRD release was shown to have implications for passenger egress  Results support the inherently safe design of hydrogen fuel cell vehicles *Highlights (for review)

Hydrogen Fuel Cell Road Vehicles and Their Infrastructure: An Option towards an Environmentally Friendly Energy Transition

“…The efficiency depends of course of the environmental operating conditions. In any case, this system permits to involve not more than a few per cent of the tank available energy which dramatically reduces the consequences of a catastrophic tank rupture [76,77]. To reinforce the FCV security, two projects are under study.…”

Numerical Simulation of Hydrogen Leakage from Fuel Cell Vehicle in an Outdoor Parking Garage

“…CFD methods have also been performed to numerically evaluate the behavior of hydrogen dispersion so that emergency measures can be taken immediately to reduce the hydrogen concentration under a lower flammable limit (LFL) [22][23][24]. H. Hussein et al [25] numerically assessed the impact of various conditions by varying leakage orifice, direction, and angle of flammable hydrogen cloud. It was concluded that a larger orifice contributes to a massive flow rate, leading to a severe pressure-peaking phenomenon.…”

Hydrogen Jet Fire from a Thermally Activated Pressure Relief Device (TPRD) from Onboard Storage in a Naturally Ventilated Covered Car Park

“…Even unignited release from TPRD in a garage-like enclosure with limited vent size may lead to the pressure peaking phenomenon [4][5][6]. In a naturally ventilated covered car park, if there is no ignition, then understanding the release and dispersion of hydrogen and subsequent formation of a flammable cloud is the primary concern to define inherently safer conditions for TPRD release from passenger vehicles; this has been the focus of a previous study by the authors [7]. However, there is a need to understand how ignition impacts upon requirements for a safer release.…”

“…It is recommended by existing standards that the ventilation rate is such that in the case of hydrogen the concentration does not exceed 1% by volume i.e., 25% of the LFL within the car park; this is specified in ISO/DIS 19880-1 [12], NFPA 2 [13] and IEC (60079-10) [14]. This was the focus of previous work by the authors where an unignited release was considered within the same covered car park geometry presented here [7]. The British Standard BS 7346-7:2013 [15] defining the code of practice for underground car parks is used as a reference for the natural ventilation requirements in [7] and in this work.…”

“…This was the focus of previous work by the authors where an unignited release was considered within the same covered car park geometry presented here [7]. The British Standard BS 7346-7:2013 [15] defining the code of practice for underground car parks is used as a reference for the natural ventilation requirements in [7] and in this work. The same code of practice provides recommendations on equipment performance in the case of mechanical ventilation as follows: "All fans intended to exhaust hot gases used within a car park ventilation system should be tested in accordance with BS EN 12101-3 to verify their suitability for operating at 300 • C for a period not less than 60 min (class F300)".…”