【摘要】 降膜脱挥具有相接触面积大、脱挥效率高、经济性好的优点，常作为从聚合物中脱除挥发性物质的重要手段，其脱挥效果与流体在落条上的降膜状态息息相关。本文选用糖浆溶液模拟聚合物系，通过漏斗降膜元件分析流体沿光滑圆条的自由降膜过程，考察了流体黏度、流量和环缝宽度对降膜的影响。结果表明：当漏斗持液器环缝处的液位压力大于表面张力时，流体通过环缝在圆条上形成降膜，且流体黏度越大，润湿性越弱，稳定成膜对应的环缝宽度越大；环缝宽度为1.5mm和2.5mm时，不同黏度的流体均能稳定成膜，为优选的环缝宽度；在确定的流体黏度或环缝宽度下，稳定降膜高度与降膜流量呈递增关系。环缝宽度越大，流体黏度越小，稳定降膜对应的流量越大；随着糖浆黏度和降膜流量增加，膜厚度逐渐增加，在考察的糖浆黏度和降膜流量范围内，膜厚度在0.94～3.48mm之间，为降膜脱挥提供了基础数据支持。更多还原

【Abstract】 Falling film de-volatilization has the advantages of large phase contact area, high devolatilization efficiency and good economy, and is often used as an important means to remove volatile substances from polymers, and its de-volatilization effect is closely related to the state of the descending film of the fluid on the falling bar. In this paper, a molasses solution was selected to simulate the polymer system, and the free film descent process of the fluid along the smooth circular bar was analyzed by the funnel film descent element, and the effects of fluid viscosity, flow rate, and annular slit width on the film descent were investigated. The results showed that when the liquid level pressure at the ring slit of the funnel holder was greater than the surface tension, the fluid formed a descending film on the circular strip through the ring slit, and the larger the fluid viscosity was, the weaker the wettability was, and the larger the ring slit width corresponded to the stabilized film. When the ring slit widths were 1.5mm and 2.5mm,the fluids with different viscosities could be stabilized to form a film, which was the preferred ring slit width. At a definite fluid viscosity or ring slit width, the stabilized descending film under the determined fluid viscosity or ring seam width, the stable falling film height had an increasing relationship with the falling film flow rate. The larger the ring seam width, the smaller the fluid viscosity, and the larger the flow rate corresponding to the stabilized descending film. With the increase of syrup viscosity and descending film flow rate, the film thickness gradually increased, and the film thickness ranged from 0.94mm to 3.48mm within the investigated range of syrup viscosity and descending film flow rate, which provided the basic data support for the descending film de-volatilization.更多还原