(A) study on the flame propagation arrest using the quenching mesh during hydrogen combustion

Abstract

The flame arrest function using the quenching mesh for hydrogen gas that is generated during severe accidents is studied for the purpose of arresting DDT and maintaining the equipment’s survivability. When considering safety, the metallic mesh with a gap distance of 0.3 mm is finally designed from the results of the quenching distances measurement. The performance test is carried out to check the flame arrest function between the compartments of the quenching mesh that is designed based on the measured quenching distance. In the quenching mesh performance test of the small-scale experimental facility (Sub-atmospheric pressure, 30% hydrogen concentration), the quenching mesh played a role of flame quenching below 0.4Bar. The flame is quenched or not quenched at 0.3Bar depending on the flame velocity. The medium-scale tests (Over atmospheric pressure, 8-10% hydrogen concentration) are carried out at the conditions over the atmospheric pressure (1.1-2.2Bar) for various hydrogen concentrations (8-10%). From the flame images and the temperatures and pressures measured during combustion, it is confirmed that the quenching mesh played a role of flame quenching up to a 10% hydrogen concentration at 1.0Bar. The quenching mesh played a role of quenching the flame with a flame velocity of 1.65m/s at 1.8Bar. However, the quenching mesh could not play a role of quenching the flame over 2.0Bar. In the medium-scale test facility, the equipment survivability test is carried to check the equipments protection in a containment using the quenching mesh. The model equipment (10cmx10cmx10cm) is located at the center of the flame passage. At an atmospheric pressure, the temperature of 100℃ at the surface of the model equipment during the hydrogen combustion is maintained at near the atmospheric pressures. The mesh played a role of protecting the equipment during the hydrogen combustion. However, the temperature at the surface of the model equipment increases to over 200℃ when the in...