Dynamic hazard evaluation of explosion severity for premixed hydrogen-air mixtures in a spherical pressure vessel

To evaluate dynamic explosion severity levels of premixed hydrogen-air mixtures, pressure sensors were used to test explosion pressure in a spherical pressure vessel (inner diameter: 0.34 m). ANSYS Fluent 19.0 three-dimensional software was used to simulate the explosion process. The results revealed that when the hydrogen volume fraction was 30 vol%, the explosion pressure and pressure rise rate reached maximum values at 1.0 atm. As the initial pressure increased, the explosion pressure, and pressure rise rate increased gradually. At initial pressures of 1.0, 1.2, 1.5, and 2.0 atm, the peak pressure levels were 0.85, 0.87, 0.92, and 0.99 MPa and the pressure rise rates were approximately 198, 241, 302, and 558 MPa/s, respectively. The initial pressure exerted greater effects on the pressure rise rate than did the explosion pressure. The simulation results were consistent with the experimental findings. Moreover, the simulation yielded multi-dimensional transient explosion parameters-such as turbulent kinetic energy distribution-that are difficult to obtain in experiments. The findings pertaining to the physical experiments, numerous simulations, and influence of initial pressure on the explosion reaction mechanism of premixed hydrogen-air mixtures were discussed.