Kuibin Zhou

Bio: Kuibin Zhou is an academic researcher from Nanjing Tech University. The author has contributed to research in topics: Jet (fluid) & Heat flux. The author has an hindex of 6, co-authored 9 publications receiving 98 citations.

Effect of wire mesh on double-suppression of CH4/air mixture explosions in a spherical vessel connected to pipelines

Abstract: Most inlets or outlets of tanks and reactors are linked vessels consisting of the tank or reactor itself and pipelines. In this study, a series of experiments was conducted to study the double-suppression effect of a multi-layer wire-mesh structure on methane-air mixture explosions in a spherical vessel connected to pipelines. The double-suppression effect was analyzed using explosion-suppression structures with different number of layers and meshes, and in particular, the effect was compared with the suppression of single-wire mesh. The results show that the explosion suppression effect primarily depends on both the number of layers and number of meshes. The number of layers plays a positive role in suppression when enough layers are used, and the number of meshes also has a significant effect on explosion suppression. It appears that the position of the wire mesh only has a slight effect on explosion suppression. The results provide a fundamental basis for actual explosion protection designs.

Effects of metal foam meshes on premixed methane-air flame propagation in the closed duct

Abstract: In many practical applications, the comprehensive measures are needed to suppress the gas explosions, and lining the channel walls with porous materials before a special installation for flame resistance is an effective choice. The aim of the present work is to investigate the effect of porous materials on the premixed flame propagation process in a closed combustion tube. Experiments are carried out to examine the flame dynamics for the stoichiometric methane/air mixtures both in the empty tube and in the presence of porous materials. The results demonstrate that the flame propagation can be divided into five typical stages, and a tri-tulip flame is observed during the development of the classic tulip flame. The inversion distance L of the flame front is selected to characterize the tulip flame evolution. It is worth to notice that the flame tip fronts travel faster with smaller porous densities PPI(pores per inch) from the finger shape stages to flat shape stages. The explosion severity parameters, including peak pressure and maximum pressure growth rates, are compared for all configurations, and the porous density plays an important role on the explosion severity. The maximum rate of pressure rise decreases linearly with the porous densities. It is deduced that the metal foam meshes with the larger porous densities PPI have more significant impacts on suppressing the tulip formation. The coupling of the flame front with the pressure wave plays a significant role in the onset and evolution of the tulip flame. As a whole, the metal foam meshes can reduce the overpressures can reduce the overpressures by33.3%–46.6%, while they have little effect on the flame tip speeds and shapes.

Brief review on passive and active methods for explosion and detonation suppression in tubes and galleries

Abstract: Gaseous and dust (including hybrid) explosions often occur in mines, grain elevators, and industrial plants, and always lead to severe damage. Strategies for suppressing or mitigating explosions are developed based on an understanding of their physical mechanism. This study briefly summarized previous studies on explosions, detonations, and the deflagration-to-detonation transition (DDT), and then discussed potential passive/active or hybrid methods for suppressing explosions and detonation in tubes and galleries. Suppression can be achieved using methods that are focused on eliminating or mitigating factors that can either promote the reactive process or break down the DDT process. These methods involve lowering temperature and pressure, diluting the mixture concentration, and venting the closed system. The method of tuning wall materials (using aerogel) is also validated for the effectiveness of detonation suppression. By using various sensors to detect propagating flames or pressure increases in tubes or galleries, active systems can disperse a suppressing agent to extinguish combustion in a timely manner. It is commonly regarded that the active systems are superior to passive methods that operate without additional control units in some ways, but there are always limitations on the application due to reasons such as the cost of equipment, regular maintenance as well as reliability of the complicated integrated-systems. Practice applications show that there is no method of explosion prevention is absolutely safe. In reality, people must consider various factors in the development of an explosion/detonation suppression system to reduce the risk to an acceptable level.