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Experimental investigation of wetting behavior of falling films inside inclined tubes

斜管内降膜下注行为的实验研究

基本信息

批准号：
234981391
负责人：
Professor Dr.-Ing. Ulrich Groß
金额：
--
依托单位：
Lehrstuhl für Technische Thermodynamik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/234981391?language=en
关键词：
Experimental investigation wetting behavior falling

项目摘要

The aim of this research project is to investigate the stability of falling films in slightly inclined evaporation tubes in dependence of internal structuring, inclination angle, fluid properties and mass flow rate. Furthermore, surfaces for a better wetting will be investigated and evaluated. Therewith forecasts concerning wetting rate, film stability and capillary transport should be possible in future. Within this research project, a test plant for falling film evaporation with the possibility of exchanging the evaporation tubes and visual access was built and an existing autoclave for contact angle measurements was enhanced.The already obtained results lead to a better understanding of the stability of a falling film in inclined internally structured tubes. The experiments with water/ air and propane conducted so far allow to draw conclusions about the wetting behavior in combination with the knowledge of contact angle, surface energy and structure. Adjustments to models for the calculation of the transport capacity within the grooves (mainly responsible for the film spreading) were realized, too. More investigations with the selected fluids deionized water and ethanol are necessary to conclude general statements about the film stability. Additionally, the measurement of the contact angle will be improved to measure drops with a smaller capillary length. The calculation of the advancing contact angle will be validated with tilting plate experiments for propane, ethanol and water, too.

本研究项目的目的是调查的内部结构，倾斜角度，流体性质和质量流率的依赖性在轻微倾斜的蒸发管中的降膜的稳定性。此外，将研究和评估更好润湿的表面。因此，有关润湿速率，薄膜稳定性和毛细运输的预测应该是可能的。在该研究项目中，我们建立了一个降膜蒸发试验装置，可以更换蒸发管和目视检查，并对现有的接触角测量高压釜进行了改进。已经获得的结果有助于更好地了解倾斜内部结构管中降膜的稳定性。迄今为止进行的水/空气和丙烷的实验允许结合接触角、表面能和结构的知识得出关于润湿行为的结论。还实现了对用于计算槽内输送能力（主要负责膜铺展）的模型的调整。有必要对所选流体去离子水和乙醇进行更多的研究，以得出关于膜稳定性的一般性声明。此外，接触角的测量将得到改进，以测量具有较小毛细管长度的液滴。推进接触角的计算也将通过丙烷、乙醇和水的斜板实验进行验证。