The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway...The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test system.We investigated the release characteristics of main energy sources in coal seam,and obtained the dynamic characteristics of outburst two-phase flow in a roadway.Additionally,we established a formation model for outburst impact flow and a model for its flow in a bifurcated structure.The results indicate that the outburst process exhibits pulse characteristics,and the rapid destruction process of coal seam and the blocking state of gas flow are the main causes of the pulse phenomenon.The outburst energy is released in stages,and the elastic potential energy is released in the vertical direction before the horizontal direction.In a straight roadway,the impact force oscillates along the roadway.With an increase in the solid–gas ratio,the two-phase flow impact force gradually increases,and the disaster range extends from the middle of the roadway to the coal seam.In the area near the coal seam,the disaster caused by the two-phase flow impact is characterized by intermittent recovery.In a bifurcated roadway,the effect of impact airflow on impact dynamic disaster is much higher than that of two-phase flow,and the impact force tends to weaken with increasing solid-gas ratio.The impact force is asymmetrically distributed;it is higher on the left of the bifurcated roadway.With an increase in the solid-gas ratio,the static pressure rapidly decreases,and the bifurcated structure accelerates the attenuation of static pressure.Moreover,secondary acceleration is observed when the shock wave moves along the T-shaped roadway,indicating that the bifurcated structure increases the shock wave velocity.展开更多
TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition...TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H-600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently. Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.展开更多
为研究气流对扩散层输水性的影响,构建二维模型表征扩散层纤维结构特征;联合VOF(Volume of Fluid)方法、N-S方程、Darcy定律及毛细压力方程,建立多孔介质内气液控制方程,跟踪气液流动界面,分析气流压力、温度和输入模式与不同孔隙率扩...为研究气流对扩散层输水性的影响,构建二维模型表征扩散层纤维结构特征;联合VOF(Volume of Fluid)方法、N-S方程、Darcy定律及毛细压力方程,建立多孔介质内气液控制方程,跟踪气液流动界面,分析气流压力、温度和输入模式与不同孔隙率扩散层水输运状态的关系,阐明气流与孔隙结构耦合作用对扩散层水分布的影响机理。结果表明:扩散层内气流分布直接影响水的输运,而气流状态与扩散层孔隙结构特征密切相关;增大气体输入间隔对于增进扩散层排水效果显著。该研究对于提升扩散层的输水性具有借鉴意义。展开更多
为提高苦荞粉面制品的适口性及保健性,选取西农9940为原料,采用新型磨粉设备气流分级式冲击磨(ACIM)对苦荞籽粒进行微粉处理,考察微粉处理对苦荞粉及其挂面品质的影响。结果表明:ACIM微粉处理有利于苦荞粉营养物质及生物活性成分的释放...为提高苦荞粉面制品的适口性及保健性,选取西农9940为原料,采用新型磨粉设备气流分级式冲击磨(ACIM)对苦荞籽粒进行微粉处理,考察微粉处理对苦荞粉及其挂面品质的影响。结果表明:ACIM微粉处理有利于苦荞粉营养物质及生物活性成分的释放,改善了苦荞粉理化特性和加工性能。其中微粉处理的苦荞粉中基本营养物质脂肪、蛋白和纤维以及功能性成分总酚、总黄酮的含量均显著上升(P<0.05);而苦荞微粉粉糊的衰减值(161 c P)和回升值(979 c P)较低,粉糊热稳定性好、不易老化。此外,ACIM微粉处理降低了苦荞挂面的体外消化速率及估计血糖生成指数(EGI)值,并改善了苦荞挂面的感官品质。采用ACIM对苦荞籽粒进行微粉加工,既保证了苦荞挂面的良好品质及感官接受度,又提高了苦荞粉中基本营养物质和功能性物质的含量,使挂面具有良好的保健功能,为提高苦荞面制品适口性和保健性以及为后续苦荞主食化的研究提供了一种可实现的加工处理方法。展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.51874055,52074047,and 52064016).
文摘The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test system.We investigated the release characteristics of main energy sources in coal seam,and obtained the dynamic characteristics of outburst two-phase flow in a roadway.Additionally,we established a formation model for outburst impact flow and a model for its flow in a bifurcated structure.The results indicate that the outburst process exhibits pulse characteristics,and the rapid destruction process of coal seam and the blocking state of gas flow are the main causes of the pulse phenomenon.The outburst energy is released in stages,and the elastic potential energy is released in the vertical direction before the horizontal direction.In a straight roadway,the impact force oscillates along the roadway.With an increase in the solid–gas ratio,the two-phase flow impact force gradually increases,and the disaster range extends from the middle of the roadway to the coal seam.In the area near the coal seam,the disaster caused by the two-phase flow impact is characterized by intermittent recovery.In a bifurcated roadway,the effect of impact airflow on impact dynamic disaster is much higher than that of two-phase flow,and the impact force tends to weaken with increasing solid-gas ratio.The impact force is asymmetrically distributed;it is higher on the left of the bifurcated roadway.With an increase in the solid-gas ratio,the static pressure rapidly decreases,and the bifurcated structure accelerates the attenuation of static pressure.Moreover,secondary acceleration is observed when the shock wave moves along the T-shaped roadway,indicating that the bifurcated structure increases the shock wave velocity.
基金Project(50372047) supported by the National Natural Science Foundation of China
文摘TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H-600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently. Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.
文摘为研究气流对扩散层输水性的影响,构建二维模型表征扩散层纤维结构特征;联合VOF(Volume of Fluid)方法、N-S方程、Darcy定律及毛细压力方程,建立多孔介质内气液控制方程,跟踪气液流动界面,分析气流压力、温度和输入模式与不同孔隙率扩散层水输运状态的关系,阐明气流与孔隙结构耦合作用对扩散层水分布的影响机理。结果表明:扩散层内气流分布直接影响水的输运,而气流状态与扩散层孔隙结构特征密切相关;增大气体输入间隔对于增进扩散层排水效果显著。该研究对于提升扩散层的输水性具有借鉴意义。
文摘为提高苦荞粉面制品的适口性及保健性,选取西农9940为原料,采用新型磨粉设备气流分级式冲击磨(ACIM)对苦荞籽粒进行微粉处理,考察微粉处理对苦荞粉及其挂面品质的影响。结果表明:ACIM微粉处理有利于苦荞粉营养物质及生物活性成分的释放,改善了苦荞粉理化特性和加工性能。其中微粉处理的苦荞粉中基本营养物质脂肪、蛋白和纤维以及功能性成分总酚、总黄酮的含量均显著上升(P<0.05);而苦荞微粉粉糊的衰减值(161 c P)和回升值(979 c P)较低,粉糊热稳定性好、不易老化。此外,ACIM微粉处理降低了苦荞挂面的体外消化速率及估计血糖生成指数(EGI)值,并改善了苦荞挂面的感官品质。采用ACIM对苦荞籽粒进行微粉加工,既保证了苦荞挂面的良好品质及感官接受度,又提高了苦荞粉中基本营养物质和功能性物质的含量,使挂面具有良好的保健功能,为提高苦荞面制品适口性和保健性以及为后续苦荞主食化的研究提供了一种可实现的加工处理方法。
