摘要
在厌氧消化反应器中,机械搅拌是广为应用的搅拌方式,但机械搅拌在运行过程中存在设备维修困难、能耗高等问题。基于前期的研究,利用Ansys 17.2软件平台,构建3 000 m~3液-液射流搅拌厌氧消化反应器1∶1仿真模型,为考察液液射流装置对热水解污泥在反应器内的搅拌混合效果,模拟得出速度云图、速度矢量图、剪切速率图以及死区分布图,并对搅拌性能、搅拌机理进行分析。结果表明:流场区域流速范围0~1.50 m·s~(-1),剪切速率范围0~200 s~(-1);依据斯托克斯定律计算出该流场中沉降速度阈值0.30 m·s~(-1),低于该速度值的部分形成死区,死区主要分布在流场中心区域,其体积为600.88 m~3,占总体积20.58%;相对于流场中心区域,流场内其他区域流速均值为0.60 m·s~(-1),得到较好的搅拌混合。
In the anaerobic digestion reactor,mechanical agitation is a widely used method of mixing,but there are difficulties in equipment maintenance and high energy consumption during the operation. Based on the previous research and Ansys 17. 2 software platform,1 ∶ 1 simulation model was constructed by simulating 3 000 m~3 anaerobic digestion reactor,equipped with liquid-liquid jet device in a sludge centralized treatment station. Velocity vector,shear rate,and dead zone profiles were used to investigate the mixing effect of liquid jet device for thermal-hydrolyzed sludge. The mixing performance and stirring mechanism are also analyzed. As a result,the velocity range of the flow field is from 0 to 1. 50 m·s~(-1) and the shear rate range is from 0 to 2. 00 s~(-1). The sedimentation velocity threshold is 0. 30 m·s~(-1) according to Stokes' s law and the volume of the part below this velocity is 600. 88 m~3,reaching 20. 58% of the total volume. Compared with the center of the flow field,the mean velocity of other regions is 0. 60 m·s~(-1) and the mixing is much better.
引文
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