摘要
根据多晶硅生产中固渣浆料的处理特点和难点,设计开发了一套连续密闭的干燥机,通过一定简化后,建立了干燥机的三维模型,并应用CFD软件Fluent14.5初步模拟了干燥机内的流体流动,计算中采用RNG_(κ-ε)湍流模型。结果表明:在辐杆与螺带和旋转锥筒连接处有大量的漩涡产生,边界层分离;在旋转锥筒和内、外螺带的搅拌作用下,流体连续流动,形成轴向、径向与切向流,湍流程度加剧;锥筒外的湍流程度比锥筒内的显著。构建了连续式双螺旋干燥机小试装置实验系统,在全满流状态下,以浓盐水代替固渣浆料进行冷模实验,研究了轴向、径向和切向三维分速度的分布特征。实验结果表明:锥筒转速和循环量对流体轴向速度作用不明显,在螺带和锥筒作用下形成的涡流具有二次导流作用,带动流体切向和径向周期运动。实验结果与流体仿真结果表现出良好的一致性,均证明了连续式密闭嵌套的双螺带干燥机设计的合理性和有效性。
Considering both characteristics and difficulties in producing polysilicon slurry, a continuous air- tight dryer was designed and 3D model was established, including making use of CFD Fluent to simulate the fluid flow in the rotating dryer and adopting RNG k-ε turbulent model in the calculation. Results show that, a large amount of vortexes arise at the radius bars where helical ribbon and rotating cone joins and boundary layer separates; under agitation of rotating cones and inner and outer helical ribbons, the fluid turbulently circulates to form into axial, radial and tangential flow and the turbulence degree outside the rotating cone is more obvious than that inside the rotating cone. An experimental device for researching fluid velocity was set up. In the condition of full flow, through replacing the polysilicon slurry with strong brine, the distribution characteristics of axial, radial and tangential three-dimensional component velocities were investigated. The experimental results show that, the rotating cone＇ s speed and fluid flow＇ s circulation volume have little effect on the axi- al velocity; and the vortex formed under the action of rotating cones and helical ribbons has secondary diVer- sion effect which drives the fluid＇ s periodic motion in axial and radial direction. Experimental results and the fluid simulation results, showing a good consistency, prove the rationality and validity of the design of the continuous airtight and nested double sprial dryer.
出处
《化工机械》
CAS
2017年第2期184-189,195,共7页
Chemical Engineering & Machinery
关键词
干燥机
多晶硅
设计开发
CFD数值模拟
冷模实验
dryer,polysilicon,design development, CFD numerical simulation, cold-modeling experiment
