基于VOF模型的水平管蒸发器液膜流动数值研究
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摘要
在水平管降膜蒸发器液体分布器的设计中,布液管结构参数影响着液体的成膜质量,为了简化设计计算,提出了利用有限元数值计算软件研究开孔间距与其他结构参数的关系。开孔间距的大小与液膜在蒸发管外壁面形成的宽度有关。而影响蒸发管外壁面液膜宽度的主要因素有2个:布液孔孔径和布液孔穿孔流速。因此,课题组采用VOF模型,模拟蒸发管外壁面液膜流动形态,探讨不同孔径和穿孔流速下的液膜宽度值,利用中心复合实验得出液膜宽度Lm(开孔间距l)关于穿孔流速v和孔径d的关系式。结果表明:通过得到的关系式可以建立3者之间的内在关系,计算出不同孔径和穿孔流速下的开孔间距值。该关系式能够简化液体分布器布液管各结构参数的设计和计算,具有一定的参考和应用价值。
In the design of the liquid distributor of the horizontal-tube falling-film evaporator,film forming quality is influenced by several structural parameters of the liquid distribution tube. The relationship between opening spacing and other structural parameters was studied by using the finite element numerical calculation software to simplify the design calculation. The distributor orifice spacing is related to the width of the liquid film formed on the outer wall of the evaporation tube. There are two main factors affecting the width of the liquid film on the outer surface of the evaporation tube: distributor orifice diameter and perforation velocity. Therefore,VOF model was used to simulate the flow pattern of liquid film on the outer wall of the evaporator tube. The width of the liquid film was calculated under different distributor orifice diameters and perforation velocities. The regression equation of the liquid film width Lm( distributor orifice spacing l),which described by distributor orifice diameters d and perforation velocities v was obtained by means of central composite experiment. The results show that the relationship between the three can be established by the obtained formula and the distributor orifice spacing of different distributor orifice diameters and perforation velocities can be calculated. This formula can simplify the design and calculation of various structural parameters of the liquid distributor,and has certain reference and application value.
In the design of the liquid distributor of the horizontal-tube falling-film evaporator,film forming quality is influenced by several structural parameters of the liquid distribution tube. The relationship between opening spacing and other structural parameters was studied by using the finite element numerical calculation software to simplify the design calculation. The distributor orifice spacing is related to the width of the liquid film formed on the outer wall of the evaporation tube. There are two main factors affecting the width of the liquid film on the outer surface of the evaporation tube: distributor orifice diameter and perforation velocity. Therefore,VOF model was used to simulate the flow pattern of liquid film on the outer wall of the evaporator tube. The width of the liquid film was calculated under different distributor orifice diameters and perforation velocities. The regression equation of the liquid film width Lm( distributor orifice spacing l),which described by distributor orifice diameters d and perforation velocities v was obtained by means of central composite experiment. The results show that the relationship between the three can be established by the obtained formula and the distributor orifice spacing of different distributor orifice diameters and perforation velocities can be calculated. This formula can simplify the design and calculation of various structural parameters of the liquid distributor,and has certain reference and application value.
引文
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[5]张晓红.基于VOF法的横管降膜蒸发传热特性的数值分析[D].大连:大连理工大学,2015:14-16.
[6]蒋维国.横管降膜流动特性与液膜分布规律的数值模拟研究[D].大连:大连理工大学,2016:16.
[7]王海涛,陈晔.水平管降膜蒸发液膜厚度及传热系数研究[J].海洋技术学报,2013,32(4):81-84.
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[2]侯淳.水平管降膜卧式蒸发器液体分布器结构设计及流量计算[J].企业科技与发展,2012(22):8-10.
[3]罗彩霞.排管式液体分布器的设计研究[J].长春理工大学学报(自然科学版),2011,34(3):122-124.
[4]赵龙陆,陈晔.影响水平管降膜蒸发因素的实验研究[J].化工机械,2014,41(1):48.
[5]张晓红.基于VOF法的横管降膜蒸发传热特性的数值分析[D].大连:大连理工大学,2015:14-16.
[6]蒋维国.横管降膜流动特性与液膜分布规律的数值模拟研究[D].大连:大连理工大学,2016:16.
[7]王海涛,陈晔.水平管降膜蒸发液膜厚度及传热系数研究[J].海洋技术学报,2013,32(4):81-84.
[8]赵婵,许松林.降膜蒸发研究进展[J].石油化工设备,2013(6):54-59.
[9]张震,张德聪.实验设计与数据评价[M].广州:华南理工大学出版社,2014:215-222.