The prediction model for explosion overpressure in unconfined hydrogen cloud explosion

The strong blast wave in gas explosion accident could cause great casualties and property loss, which is the main threat to safety production and further popularization of hydrogen energy. This research focuses on the prediction of explosion overpressure in unconfined hydrogen cloud explosion with or without built-in obstacle. The flame acceleration caused by the obstacle causes two overpressure peaks. As the flame is accelerated by multilayer obstacle, the positive overpressure peak is reached when the flame is still in the congested region. Based on the fractal factor, the prediction for overpressure and impulse curve is achieved and a prediction model for positive overpressure and impulse peak is proposed without built-in obstacle. For congested condition, a parameter E is proposed and its value is linear with the propagation distance in the semi-logarithmic coordinate. The flame propagation process is divided into four regions according to the space position. Based on the prediction of E, the prediction of positive overpressure impulse peak and upper limit of positive overpressure peak is achieved.