Comparisons of hazard distances and accident durations between hydrogen vehicles and CNG vehicles

Li, Zhiyong; Luo, Yiying

doi:10.1016/j.ijhydene.2018.07.074

Cited by 12 publications

(4 citation statements)

References 4 publications

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“…Thus, these structures-whatever form they take later on-are the main mechanisms that transfer hydrogen upwards, towards the ceiling (crown) of the tunnel. Similar blister-like structures can be noticed in many studies [22,[27][28][29][30]34]. The accurate shape and position of these structures depend on many physical and simulation parameters, and the particular shapes should be considered as indicative.…”

Section: First Thirty Seconds Of the Releasesupporting

confidence: 67%

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Numerical Investigation of Hydrogen Jet Dispersion Below and Around a Car in a Tunnel

Koutsourakis,

Tolias,

Giannissi

et al. 2023

Energies

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Accidental release from a hydrogen car tank in a confined space like a tunnel poses safety concerns. This Computational Fluid Dynamics (CFD) study focuses on the first seconds of such a release, which are the most critical. Hydrogen leaks through a Thermal Pressure Relief Device (TPRD), forms a high-speed jet that impinges on the street, spreads horizontally, recirculates under the chassis and fills the area below it in about one second. The “fresh-air entrainment effect” at the back of the car changes the concentrations under the chassis and results in the creation of two “tongues” of hydrogen at the rear corners of the car. Two other tongues are formed near the front sides of the vehicle. In general, after a few seconds, hydrogen starts moving upwards around the car mainly in the form of buoyant blister-like structures. The average hydrogen volume concentrations below the car have a maximum of 71%, which occurs at 2 s. The largest “equivalent stoichiometric flammable gas cloud size Q9” is 20.2 m3 at 2.7 s. Smaller TPRDs result in smaller hydrogen flow rates and smaller buoyant structures that are closer to the car. The investigation of the hydrogen dispersion during the initial stages of the leak and the identification of the physical phenomena that occur can be useful for the design of experiments, for the determination of the TPRD characteristics, for potential safety measures and for understanding the further distribution of the hydrogen cloud in the tunnel.

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Section: First Thirty Seconds Of the Releasesupporting

confidence: 67%

“…More recently, Li and Luo [27]-along with the previous work of Li et al [28]examined the dispersion around a car in the open atmosphere due to a downwards hydrogen leakage from a Thermally Activated Pressure Relief Device (TPRD) of 4.2 mm. Tank pressures of both 350 and 700 bars were examined, and the geometry of a real car was reproduced.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Hydrogen Jet Dispersion Below and Around a Car in a Tunnel

Koutsourakis,

Tolias,

Giannissi

et al. 2023

Energies

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“…However, Li et al [28] focused on releases in an open atmosphere without confinement and a relatively big TPRD diameter compared to this study. In recent work by Li and Luo [29], the same release diameters and conditions for ignited hydrogen were compared with CNG (methane) releases, and it was found that the CNG jet fire duration was twice that of the hydrogen jet fire. Their study was also in the open atmosphere without any obstructions.…”

Section: ° Release Angle With the Vertical Axismentioning

confidence: 99%

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

Hussein¹,

Brennan

Molkov

2021

Hydrogen

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Hydrogen jet fires from a thermally activated pressure relief device (TPRD) on onboard storage are considered for a vehicle in a naturally ventilated covered car park. Computational Fluid Dynamics was used to predict behaviour of ignited releases from a 70 MPa tank into a naturally ventilated covered car park. Releases through TPRD diameters 3.34, 2 and 0.5 mm were studied to understand effect on hazard distances from the vehicle. A vertical release, and downward releases at 0°, 30° and 45° for TPRD diameters 2 and 0.5 mm were considered, accounting for tank blowdown. direction of a downward release was found to significantly contribute to decrease of temperature in a hot cloud under the ceiling. Whilst the ceiling is reached by a jet exceeding 300 °C for a release through a TPRD of 2 mm for inclinations of either 0°, 30° or 45°, an ignited release through a TPRD of 0.5 mm and angle of 45° did not produce a cloud with a temperature above 300 °C at the ceiling during blowdown. The research findings, specifically regarding the extent of the cloud of hot gasses, have implications for the design of mechanical ventilation systems.

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“…Hydrogen fuel is a kind of green, renewable, clean energy source that can provide powerful output for automobiles, and it has a very huge development potential [1][2][3][4][5][6][7]. Hydrogen storage is the largest constraint on hydrogen engines and hydrogen fuel cells used in electric vehicles and hybrid electric vehicles [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Thermal Effect and Heat Control Strategy of Magnesium-Based Hydrogen Storage Alloy System for Lightweight Automobile

Li¹,

Liu²,

Jing³

et al. 2022

IJHT

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The magnesium-based hydrogen storage alloy has a very good prospect to be applied in the market of lightweight automobile due to its merits of light weight, excellent discharge performance, long cycle life, and large hydrogen storage capacity. However, existing studies on magnesium-based hydrogen storage alloy have a series of shortcomings such as the insufficient works in terms of model reasonability analysis, heat transfer behavior analysis, heat control scheme design, and comparative experiment analysis, etc. In view of these problems, this paper studied the thermal effect and heat control strategy of the Mg-based Hydrogen Storage Alloy (MHSA) system for lightweight automobile. At first, this paper constructed numerical models for the fluid-solid coupled heat exchange region and the heat conduction region in the system; then, based on the law of energy conservation, a heat transfer behavior model of the MHSA system was established and used to analyze the thermal effect of the system. After that, according to the driving process of hydrogen fuel cell electric vehicle, the working process of the MHSA system was further analyzed to study the heat control process. Next, this paper proposed a new idea for the heat control of the MHSA system, gave a few tips for the simulations, and presented the flow of the heat control scheme of the system. At last, the experimental results were given and analyzed.

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Comparisons of hazard distances and accident durations between hydrogen vehicles and CNG vehicles

Cited by 12 publications

References 4 publications

Numerical Investigation of Hydrogen Jet Dispersion Below and Around a Car in a Tunnel

Numerical Investigation of Hydrogen Jet Dispersion Below and Around a Car in a Tunnel

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

Thermal Effect and Heat Control Strategy of Magnesium-Based Hydrogen Storage Alloy System for Lightweight Automobile

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