Numerical investigation of the dispersion features of hydrogen gas under various leakage source conditions in a mobile hydrogen refueling station

The operation of mobile hydrogen refueling stations will be popular for hydrogen energy supply in the future, and the investigation includes the hydrogen diffusion behavior of hydrogen leakage and the potential risk of explosion is pivotal to commercializing the mobile hydrogen refueling station. The dispersion of hydrogen leakage and the minimum safe distance of explosion of the mobile hydrogen refueling station are studied by simulation. The 3D full-scale geometry is established. Experimental data verifies the numerical models. The effects of the ventilation scenarios of the truck container and the ambient wind (wind speeds and wind directions) on hydrogen volume and diffusion distance are analyzed. By calculating the severe working conditions results, the hydrogen volume in the open space and the hydrogen concentration in the four 3-way corners of the ceiling in the truck container are obtained. Finally, the overpressure caused by hydrogen explosion is evaluated, and the minimum safe distance under different damage effects is predicted. The obtained results reveal that the conditions included that the side door and side window are open, low ambient wind speed, and wind direction from front to rear of the mobile hydrogen refueling station increase the risk of hydrogen leakage and diffusion. Based on severe working conditions, the average hydrogen volume is 87.9 m3 in the air in stable status. In the case of a hydrogen explosion, the minimum safe distance is 313.2 m. The investigation provided a valuable reference for evaluating and preventing hydrogen leakage accidents of the mobile hydrogen refueling station. 

Safety analysis of hydrogen leakage accident with a mobile hydrogen refueling station

Experimental study on the effect of diluent gas on H2/CO/air mixture turbulent premixed flame

With the widespread use of substations around the world, oil jet fire accidents from transformer oil-filled equipment in substations caused by faults have occurred from time to time. In this paper, a series of transformer oil jet fire experiments are carried out by changing the external heat source (30 cm and 40 cm) and the inner diameter of the container (5 cm, 8 cm and 10 cm) to study the axial centerline temperature distribution of the transformer oil jet fire plume of the transformer oil-filled equipment in the substation. The experiment uses K-type thermocouple, electronic balance and CCD to measure and assess the temperature distribution of the axial centerline of the fire plume of the transformer oil jet. The result demonstrates that the axial centerline temperature of the fire plume increases with the external heat release rate and the inner diameter of the container. In addition, a novel axial temperature distribution prediction model of the transformer oil jet fire plume is established. This model can effectively predict the oil jet fire plume temperature of transformer oil- filling equipment in substations, and provide help for substation fire control.

Kewei Jiang

Papers

Macroscopic characteristics and prediction model of horizontal extension length for syngas jet flame under inclined conditions