Powder compaction is one of the most crucial processes in initiating explosive device manufacturing. The quality of powder compaction may influence the performances of product directly. Traditional powder compaction m...Powder compaction is one of the most crucial processes in initiating explosive device manufacturing. The quality of powder compaction may influence the performances of product directly. Traditional powder compaction mainly makes use of manual gravitational spiral loading machine or lever loading machine. Potential accident by the strike in powder compaction of initiating explosive device could risk life, property and the environment. To prevent this risk, automatic control system and control strategy can be used to guarantee no strike in pressing process. The scope of this paper is to analyze and review the control strategy for powder compact and discuss the experimental results for the application of the proposed strategy.展开更多
Using a 20 L spherical explosion suppressing test system, the largest gas explosion pressure and maximum pressure rising rate with additives of ultra-fine ABC dry powder and diatomite powder were tested and compared, ...Using a 20 L spherical explosion suppressing test system, the largest gas explosion pressure and maximum pressure rising rate with additives of ultra-fine ABC dry powder and diatomite powder were tested and compared, and the explosion suppression effect of the two kinds of powder was analyzed. Experimental results show that both powders can suppress gas ex- plosion and ABC dry powder is superior to diatomite powder. Adding two powders under the same experimental conditions, when methane concentration is 7.0%, the maximum explosion pressure decreased 39% and 4%, respectively, while the rising rate of the maximum pressure decreased 80% and 53%, respectively. When methane concentration is 9.5%, the maximum ex- plosion pressure decreased 14% and 12%, respectively, the rising rate of maximum pressure decreased 62% and 27%, respec- tively, the maximum explosion pressure decreased 23% and 18%, respectively, while the rising rate of the maximum pressure decreased 77% and 70%, respectively. When methane concentration is 12.0%, the explosion suppression effect of ultra-fine ABC dry powder is not affected by the methane concentration, and the explosion suppression effect of diatomite powder under high methane concentrations is more obvious.展开更多
The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm an...The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm and 75 μm aluminum powders were investigated by using a 20 L spherical explosion cavity and a horizontal pipe whose cross-section area is 80 mm × 80 mm and length is 8 m. The results show that the maximum explosion pressure and its rising rate of 100 nm aluminum powder gradually increase with increasing concentration of aluminum-powder at the beginning. When aluminum-powder concentration is I kg/m3, the maximum explosion pressure reaches its maximum, and then gradually decreases. While when the concentration is 1.25 kg/m3, the maximum rate of pressure rise obtains its maximum, and then decreases. After 100 nm aluminum powder is exploded in pipes, the peak overpressure of blast wave first decreases and then increases to the maximum at a distance of 298 cm from the ignition source, and then gradually decreases. The most violent concentration is about 0.4 kg/m3 which is lower than 0.8 kg/m3 of 75 μm aluminum powder, so 100 nm aluminum powders are more easily exploded. The change laws of maximum explosion pressure, maximum rate of pressure rise and blast-wave peak overpressure of 100 nm aluminum powders with concentration are similar to those of 75 ktm aluminum powders, but these values are much higher than 75 Bm aluminum powders under the same concentration, so the aluminum-powders explosion of 100 nm will produce more harms. In the process of production, storage and transportation of aluminum powder, some relevant preventive measures can be taken to reduce the loss caused by aluminum-dust explosion according to nano-aluminum dust.展开更多
文摘Powder compaction is one of the most crucial processes in initiating explosive device manufacturing. The quality of powder compaction may influence the performances of product directly. Traditional powder compaction mainly makes use of manual gravitational spiral loading machine or lever loading machine. Potential accident by the strike in powder compaction of initiating explosive device could risk life, property and the environment. To prevent this risk, automatic control system and control strategy can be used to guarantee no strike in pressing process. The scope of this paper is to analyze and review the control strategy for powder compact and discuss the experimental results for the application of the proposed strategy.
基金Supported by the Natural Science Foundation of China （50904049） the Development Fund Project of Xi＇an University of Science and Technology （2010047） the Shaanxi Provincial Scientific and Technological Fund （2010KJXX-08）
文摘Using a 20 L spherical explosion suppressing test system, the largest gas explosion pressure and maximum pressure rising rate with additives of ultra-fine ABC dry powder and diatomite powder were tested and compared, and the explosion suppression effect of the two kinds of powder was analyzed. Experimental results show that both powders can suppress gas ex- plosion and ABC dry powder is superior to diatomite powder. Adding two powders under the same experimental conditions, when methane concentration is 7.0%, the maximum explosion pressure decreased 39% and 4%, respectively, while the rising rate of the maximum pressure decreased 80% and 53%, respectively. When methane concentration is 9.5%, the maximum ex- plosion pressure decreased 14% and 12%, respectively, the rising rate of maximum pressure decreased 62% and 27%, respec- tively, the maximum explosion pressure decreased 23% and 18%, respectively, while the rising rate of the maximum pressure decreased 77% and 70%, respectively. When methane concentration is 12.0%, the explosion suppression effect of ultra-fine ABC dry powder is not affected by the methane concentration, and the explosion suppression effect of diatomite powder under high methane concentrations is more obvious.
基金supported by the Major State Basic Research Development Program of China (No. 2011CB201205)the Open Fund Program of the State Key Laboratory of Explosion Science and Technology (No. KFJJ10-19M)
文摘The explosive characteristics of aluminum powder have great significance in preventing and controlling aluminum-dust explosion accidents, especially the nano-aluminum powder. The explosion characteristics of 100 nm and 75 μm aluminum powders were investigated by using a 20 L spherical explosion cavity and a horizontal pipe whose cross-section area is 80 mm × 80 mm and length is 8 m. The results show that the maximum explosion pressure and its rising rate of 100 nm aluminum powder gradually increase with increasing concentration of aluminum-powder at the beginning. When aluminum-powder concentration is I kg/m3, the maximum explosion pressure reaches its maximum, and then gradually decreases. While when the concentration is 1.25 kg/m3, the maximum rate of pressure rise obtains its maximum, and then decreases. After 100 nm aluminum powder is exploded in pipes, the peak overpressure of blast wave first decreases and then increases to the maximum at a distance of 298 cm from the ignition source, and then gradually decreases. The most violent concentration is about 0.4 kg/m3 which is lower than 0.8 kg/m3 of 75 μm aluminum powder, so 100 nm aluminum powders are more easily exploded. The change laws of maximum explosion pressure, maximum rate of pressure rise and blast-wave peak overpressure of 100 nm aluminum powders with concentration are similar to those of 75 ktm aluminum powders, but these values are much higher than 75 Bm aluminum powders under the same concentration, so the aluminum-powders explosion of 100 nm will produce more harms. In the process of production, storage and transportation of aluminum powder, some relevant preventive measures can be taken to reduce the loss caused by aluminum-dust explosion according to nano-aluminum dust.
