文丘里粉体喷射器内部颗粒运动特性的联合仿真
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摘要
采用计算流体力学-离散单元法(CFD-DEM)耦合方法,对文丘里粉体喷射器内部5种不同粒径球形颗粒组成的颗粒群的气力输送过程进行数值模拟;分析颗粒的运动轨迹,发现部分颗粒在吸收室的底部聚集,颗粒在文丘里喷射器内部的运动集中分布在输送管道的中下部位,小尺寸颗粒速度较快,颗粒尺寸越大,颗粒与颗粒碰撞次数越多,颗粒与壁面碰撞次数越少;采用离散单元法-有限单元分析(DEM-FEA)耦合方法对颗粒与壁面碰撞引起的壁面应力变化进行分析。结果表明,喷射器在喷嘴出口处附近和吸收室底部出现应力峰值。
The pneumatic conveying process of Venturi powder injector was simulated by using the method of computational fluid dynamics-discrete element method(CFD-DEM) coupling,internal particle group was composed of five different diameters particles. The trajectories of particles were analyzed, part of particles gather together at the bottom of the absorption section.Most of the particles distribute in the middle and lower parts of pipelines in venturi powder ejector, small size particles are faster.The greater the particle size is, the more particle-particle collisions are and the less particle-wall collisions are. Analysis of the wall stress change due to the impact of particles was carried out by using the method of discrete element method-finite element analysis(DEM-FEA) coupling. It results that there is peak stress near the nozzle exit and the bottom of the absorbed section.
The pneumatic conveying process of Venturi powder injector was simulated by using the method of computational fluid dynamics-discrete element method(CFD-DEM) coupling,internal particle group was composed of five different diameters particles. The trajectories of particles were analyzed, part of particles gather together at the bottom of the absorption section.Most of the particles distribute in the middle and lower parts of pipelines in venturi powder ejector, small size particles are faster.The greater the particle size is, the more particle-particle collisions are and the less particle-wall collisions are. Analysis of the wall stress change due to the impact of particles was carried out by using the method of discrete element method-finite element analysis(DEM-FEA) coupling. It results that there is peak stress near the nozzle exit and the bottom of the absorbed section.
引文
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[2]WANG X F,JIN B S,XIONG Y Q,et al.Flow behaviors of gassolid injector by 3D simulation with kinetic theory of granular flow[J].Chinese Journal of Chemical Engineering,2008,16(6):823-831.
[3]TRIPATHI N,SHARMA A,MALLICK S S,et al.Energy loss at bends in the pneumatic conveying of fly ash[J].Particuology,2015,21:65-73.
[4]KRUGGELl-EMDEN H,OSCHMANN T.Numerical study of rope formation and dispersion of non-spherical particles during pneumatic conveying in pipe[J].Powder Technology,2014,268:219-236.
[5]HIROTA M,SOGO Y,MARUTANIC T,et al.Effect of mechanical properties of powder on pneumatic conveying in inclined pipe[J].Powder Technology,2002,122:150-155.
[6]朱步范,贾德刚,黄晓军.粉体机械输送设备与气力输送设备应用比较[J].工程建设与设计,2005(10):48-50.
[7]ZHOU Y M,SUN Z N,GU H F,et al.Structure design on improving injection performance for Venturi scrubber working in self-priming mode[J].Progress in Nuclear Energy,2015,80:7-16.
[8]JI D,ZHANG M L,XU T G,et al.Experimental and numerical studies of the jet tube based on Venturi effect[J].Vacuum,2015,111:25-31.
[9]LIU K,LU H F,GUO X L,et al.Experimental study on flow characteristics and pressure drop of gas-coal mixture through Venturi[J].Powder Technology,2014,268:401-411.
[10]谢菲,吴占松.文丘里管内气固两相流流动的数值模拟和实验[J].动力工程,2007,27(2):237-241.
[11]董宝川,刘雪东,苏世卿.基于CFD-DEM耦合法的固定床管式反应器流体流动特性数值模拟[J].中国粉体技术,2015,21(4):11-14.
[12]喻黎明,邹小艳,谭弘,等.基于CFD-DEM耦合的水力旋流器水沙运动三维数值模拟[J].农业机械学报,2016,47(1):126-132.
[13]杜俊,胡国明,方自强,等.弯管稀相气力输送CFD-DEM法数值模拟[J].国防科技大学学报,2014,36(4):134-138.
[14]吴健伟.粉煤灰气力输送喷射器的设计及应用[J].应用能源技术,2010(10):40-42.
[15]XIONG Y Q,ZHANG M Y,YUAN Z L.Three-dimensional numerical simulation method for gas-solid injector[J].Powder Technology,2005,160:180-189.