为研究增温搅拌系统对沼气进料池温度场的影响,采用计算流体动力学方法,以唐山某养牛场中覆盖有阳光板的方形进料池为研究对象,建立物理模型,以进料池中螺旋加热盘管的不同供水方式,搅拌器不同运行方式、倾角和池体的形状为影响因素对沼液温度场进行优化研究。通过对比模拟与实测数据验证模型的可靠性。最后,以X=0截面为基准面,绘制温度云图,并将沼液温度按不同区间分成低温区、中温区和高温区,统计3个区间所占比例。结果表明,加热盘管采用下供上回的形式有利于沼液升温,可消除低温区,并将中温区占比从原先的92.15%提升到98.01%,增长6.4%。搅拌器可改善高温沼液集中在盘管周围的情况,在此基础上采用两个不同转向的搅拌器,可将高温区占比从原来的1.99%提升到5.26%,增长166%。搅拌器的倾角不宜设置过大,设置成45°更为合适。在加热条件和搅拌器参数相同的前提下,方形池与圆形池在低温和高温区比例接近,但圆形池的中温区比例比方形池多2%。圆形池的中温区比例更高,搅拌死区更小,搅拌效果更好。
Abstract
The heating stirring system can improve the temperature and uniformity of the biogas slurry in the biogas feeding tanks, and effectively increase the biogas production. In order to study the effect of the heating stirring system on the temperature distribution of the biogas feeding tanks, using the computational fluid dynamics, the physical model was established on a square feeding tank, which was covered with hollow polycarbonate panels in a cattle farm in Tangshan. The temperature distribution of biogas slurry was optimized by using different water supply modes of helical heating coil tube heat exchangers, different operation modes and obliquity angles of agitators, and square or circle of tank body shape. The reliability of the model is verified by comparing the simulated and measured data. Finally, the temperature cloud diagrams were drawn on the base of section X=0, and the biogas slurry temperature was divided into low temperature zone, middle temperature zone and high temperature zone according to different intervals. The results show that the heating coil adopts the form of lower supply and upper return, which is beneficial to the temperature rise of biogas slurry and can eliminate the low temperature zone and increase the proportion of the middle temperature zone from 92.15% to 98.01%, with an increase of 6.4%. The agitators can improve the uniformity of the temperature. On this basis, using two agitators with different steering can increase the proportion of high-temperature zone from 1.99% to 5.26%, with an increase of 166%. The inclined angle of agitators should not be set too large, 45°is a suitable angle. Under the same heating conditions and agitator parameters, the proportion of low and high temperature zone is close between square tank and circular tank, but the proportion of middle temperature zone of circular tank is 2% more than that of square tank. The proportion of medium temperature zone is higher, the mixing dead zone is smaller and the mixing effect is better.
关键词
进料池 /
计算流体动力学 /
温度场 /
搅拌器 /
螺旋盘管
Key words
feeding tank /
computational fluid dynamics（CFD） /
temperature field /
stirrer /
helical coiled tube
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基金
山西省科技厅中央引导地方科技发展资金项目（YDZJSX2021A022）
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