不同结构粒化器表面高炉渣液膜的流动特性

在高炉渣离心粒化热回收工艺中,粒化得到的颗粒尺寸对余热回收效果至关重要,而颗粒尺寸又与粒化器表面液膜的流动特性息息相关,因此增进对粒化器表面液膜流动特性的认识可为离心粒化技术提供指导。采用数值模拟方法研究了离心粒化过程中粒化器结构对液膜流动的影响;讨论了半径、倾角、深度等参数对粒化器表面液膜厚度的影响及其作用机理,并获取了流体在粒化器表面运动轨迹与液膜厚度的关系。结果表明:转杯粒化器的内倾角介于40°~60°之间或深度介于10~12mm之间时粒化效果最佳,其相应液膜厚度约为0.300mm。与等径的转盘粒化器相比,其液膜厚度减小约32%。粒化器结构对液膜厚度的影响可归因于粒化器表面流体运动轨迹长度的变化,当流体运动轨迹长度增大时,其对应的液膜厚度就越小,二者呈非线性负相关关系。

Flow characteristics of molten blast furnace slag film on rotary atomizers with various configurations

In the process of centrifugal granulation integrated with heat recovery from blast furnace slag,granula-tion manufacturing blast furnace slag particles in small size is important for subsequent heat recovery.Meanwhile, the particle size depends on the film characteristics of molten slag on the atomizer.Therefore,a good understand-ing of the slag film flow can provide good guidance for centrifugal granulation.The effect of atomizers with differ-ent configurations on slag film flow was investigated by numerical simulation.The influences of atomizer radius, atomizer angle and atomizer depth on slag film thickness were discussed in detail.Moreover,the mechanism of the film flow variation caused by atomizer configuration has been theoretically explored,which aimed to obtain the re-lationship between slag film traj ectory and slag film thickness.The results showed that the rotary cup atomizers with either the inner angle ranging from 40°to 60°or the depth ranging from 10 mm to 12 mm can produce slag film of 0.300 mm.The rotary cup atomizers have been considered more suitable for centrifugal granulation for its abili-ty to decrease the film thickness by 32% in comparison with that formed on rotary disc atomizers with the same ra-dium.The influences of atomizer configurations on slag film thickness can be ascribed to the variation of liquid traj ectory length on the atomizer.Namely,the slag film thickness trends to decrease nonlinearly with increasing the liquid traj ectory length on the atomizer.