【摘要】 利用由高速数字摄影设备及大功率激光构成的测试系统在一截面为200mm×200mm、高为4m的冷态循环流化床实验台上进行了床内颗粒旋转特性的实验研究.对在距布风板3·54m高度的稀相区的1/4截面内13个测试点拍摄获得的图像序列利用Matlab、PhotoShop和ACDSee软件进行分析处理,采用人工直接判别获得颗粒转速,用双帧频验证法进行颗粒转速校验.结果表明:循环流化床气固两相流中固相颗粒普遍存在旋转现象,截面边壁区内的颗粒平均转速高于中心区域;粒径小或径向速度大的颗粒,其平均转速较大,反之亦然;不规则颗粒的平均转速明显高于球形颗粒;当空截面气体速度Vg=5m·s-1,固体质量循环流率Gs=1·5kg·m-2·s-1,玻璃珠颗粒平均粒径dp=0·5mm时,颗粒转速最高可达2000r·s-1,平均转速300r·s-1.更多还原

【Abstract】 By using an advanced measurement system composed of a high-speed digital video camera and a high-power laser sheet, an experimental research was carried out on the particle rotation characteristics in a cold Circ ulating Fluidized Bed (CFB) riser with square cross-sectional area of 200 mm×2 00 mm and height of 4 m.Particle movement images were analyzed with Matlab, Phot oShop and ACDSee software, captured at 13 measurement points in a quarter of a c ross-section in the upper dilute phase area of the CFB riser.Particle rotation speed was observed and checked by the dual-frequency method. The results showe d that the particle rotated when moving along the riser in gas-solid two-phase flow of the CFB riser, and the average particle rotational speed in the wall ar ea was higher than that in the center area in the testing cross-section. Those particles, with either relatively smaller diameter or higher radial component o f velocity,were inclined to have a higher rotational speed. The average rotatio nal velocity of irregular particles was obviously higher than that of regular on es.Average particle rotational velocity in the CFB riser was 300 r·s-1 and maximum rotational velocity was 2000 r·s-1 at superficial gas velo city V_g=5 m·s-1,recycling solids mass flux G_s=1.5 kg·m- 2·s-1 and particle average diameter d_p=0.5 mm.更多还原