Numerical and Experimental Study on the Deflagration Characteristics of Premixed CO in a Tube with Obstacles

Abstract

As the main by-product of converter steelmaking process, converter gas has significant potential for energy recovery due to its high calorific value. However, there is a significant risk of explosion during the recycling process. In order to ensure the process safety of converter gas recovery and achieve efficient energy utilization, it is necessary to study the process of CO deflagration in the tube and prevent it. This article combines experiments and numerical simulations to study the effects of obstacles inside tube, water content in the air, and the length of the smooth section on CO deflagration characteristics. The results show that the propagation characteristics of flames in the smooth section are related to the flow field and have periodicity. The length of the smooth section does not significantly affect the maximum deflagration pressure. During the propagation of flames in the obstacle section, the acceleration effect of each obstacle on the flame is similar, and the deflagration becomes more and more intense as the number of obstacles increases. The peak value is reached at the last obstacle, about 0.72 MPa, and the flame speed can reach 672 m/s. The water content in the air has a significant impact on the maximum deflagration pressure of CO, as H₂O triggers a series of chain branching reactions. When the water content increases to 0.39%, the maximum deflagration pressure reaches its peak. In terms of numerical simulation, the reliability of the open-source combustion solver XiFoam was verified. The combustion, transport, and thermodynamic property parameters for premixed gas of CO and humid air were provided using Cantera. Finally, in order to avoid the occurrence of deflagration during the converter gas recovery process, it is necessary to strictly control its moisture content.