微流控空气取水装置的热力学特性研究

发布时间：2018-07-03 10:06

本文选题：空气取水 + 微流控　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：淡水作为人类生存必需资源,具有可直接利用总量少、地理分布不均、受污染情况日益严重等问题。为此,许多生产淡水、提高水资源利用率的手段应运而生。在野外探险、科考、旅行时,经常会遇到沙漠、热带雨林、高原等难以找到足够清洁淡水的地方,而携带大量淡水又存在增加负重、无法补给等问题。因此,一种能够提供适宜饮用的清洁淡水并且方便携带的装置,对于在条件苛刻的户外环境中满足使用者的饮水需求,保障生命安全是十分重要的。本文结合吸附解析式取水原理,将聚二甲基硅氧烷(Polydimethylsiloxane,PDMS)材料应用到空气取水装置中,提出了一种可循环反复地对空气中的水蒸汽进行收集、并将其转变成淡水的便携微型装置,即一种微流控空气取水装置。本文对微流控空气取水装置的工作原理进行研究,对空气取水过程进行数学建模。基于流体力学基本理论,建立微流道内液体流动的数学模型,分析气液两相流在微流道中的流动规律,结合热力学原理,建立微流控装置中的气—液两相变化过程的热流耦合数学模型。通过数值计算对装置内水的蒸发和冷凝等热流耦合场的动态特性进行模拟分析。利用ANSYS ICEM CFD软件对微流道进行三维建模,并对三维模型进行网格划分及边界条件设置,用FLUENT软件对冷凝过程进行仿真分析,得到微流道内的流场、温度场及气相体积分数分布变化特性。利用COMSOL多物理场仿真软件对加热蒸发的解析释放过程进行二维动态模拟,得到取水容腔内的流场、温度场及气相体积分数分布变化特性。对微流控空气取水装置的制备和工作过程进行实验研究。研究软刻蚀工艺制作微流控芯片的方法,采用红外热像仪对取水过程的温度场进行观测,得到了实验条件下蒸发冷凝过程的温度分布规律,验证仿真分析结果,从而为微流控空气取水装置的设置提供了理论依据。
[Abstract]:As a necessary resource for human survival, fresh water has many problems, such as low total direct utilization, uneven geographical distribution and increasingly serious pollution. For this reason, a lot of production fresh water, the means that raises water resource efficiency arises at the historic moment. In the field of exploration, scientific research, travel, often encounter desert, tropical rain forest, plateau and other difficult to find enough clean fresh water, and carrying a large amount of fresh water has the problem of increasing load, unable to supply, and so on. Therefore, a device which can provide clean fresh water suitable for drinking and is easy to carry is very important to meet the drinking water needs of users in the harsh outdoor environment and to ensure the safety of life. In this paper, based on the principle of adsorptive and analytical water intake, the polydimethylsiloxane (PDMS) material was applied to the air water collection unit. A portable micro device for collecting water vapor in the air repeatedly and turning it into fresh water was proposed. The utility model relates to a microfluidic air water intake device. In this paper, the working principle of microfluidic air water intake device is studied, and the mathematical model of air water intake process is established. Based on the basic theory of fluid mechanics, the mathematical model of liquid flow in microchannel is established, and the flow law of gas-liquid two-phase flow in microchannel is analyzed. A coupled heat flux mathematical model for the gas-liquid two-phase variation process in a microfluidic device is established. The dynamic characteristics of coupled heat flux fields such as evaporation and condensation of water in the plant are simulated and analyzed by numerical calculation. Using ANSYS ICEM CFD software to model the microchannel, mesh the 3D model and set the boundary conditions, and use fluent software to simulate and analyze the condensation process, and obtain the flow field in the microchannel. The variation of temperature field and gas phase volume fraction distribution. By using COMSOL multi-physical field simulation software, the two-dimensional dynamic simulation of the analytical release process of heating evaporation was carried out, and the variation characteristics of the flow field, temperature field and gas phase volume fraction distribution in the water intake chamber were obtained. The preparation and working process of the micro-fluidic air water intake device were studied experimentally. The method of fabricating microfluidic chip by soft etching process is studied. The temperature field of the water intake process is observed by infrared thermal imager. The temperature distribution of evaporative condensation process is obtained under the experimental conditions, and the simulation results are verified. Thus, it provides a theoretical basis for the installation of microfluidic air intake device.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN492

【引证文献】