液滴在蒸汽携带下撞击丝网除沫器的模拟研究

发布时间：2018-01-13 23:11

本文关键词：液滴在蒸汽携带下撞击丝网除沫器的模拟研究　出处：《大连理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：丝网除沫器广泛应用于热法海水淡化装置中,用来除去蒸汽中携带的海水液滴。如果除沫器不能有效的将液滴分离下来,会造成蒸馏水品质的下降和冷凝器中蒸汽走管内的结垢与腐蚀。除沫效率和压降是丝网除沫器的两项重要的性能指标。目前针对丝网除沫器性能进行的研究仍然比较少。一部分研究者通过实验获得除沫效率和压降的半经验公式,还有一少部分研究者通过CFD模拟获得计算丝网除沫器性能的有效模型。本文使用多孔介质和交错矩阵两种模型对丝网除沫器进行建模,并深入分析了丝网除沫器性能的影响因素。丝网除沫器性能的研究对工程应用有实际意义,首先除沫器的性能对海水淡化装置的总传热面积影响很大,这与工厂的资本成本有着直接联系。其次,除沫器的性能还会影响产品水水质,这也关乎工厂的运营成本。另外,本文研究具有一定的创新性,有助于指导丝网除沫器性能的进一步研究。本文的主要研究内容如下： 1.首先将丝网除沫器假设为多孔介质,探讨了气体流速、网丝直径、填充密度对干压降的影响。 2.利用交错矩阵模型对不同结构参数和运行条件下丝网除沫器的内部流场进行了数值模拟,获得网丝捕集效率和压力梯度,从而可以计算出丝网除沫器的除沫效率和压降。研究了丝网除沫器的网丝直径、填充率、厚度对除沫效率的影响,以及斯托克斯数与网丝捕集效率的关系。另外,引入除沫器品质来综合评价不同结构除沫器的性能。 3.基于响应曲面法,利用统计分析软件Design-Expert得到除沫效率、压降和除沫器品质的预测模型,并根据响应曲面和等高线图对影响因子间的交互作用进行了分析评价。本文的预测模型可以直观的反应丝网除沫器的结构参数和运行条件对除沫器性能的影响,并有助于丝网除沫器的优化设计。
[Abstract]:Wire mesh demister is widely used in thermal seawater desalination device, used to remove steam carried in seawater droplets. If the demister can not effectively the separation of liquid drops down, will cause the steam distilled water quality decline and go in the condenser fouling and corrosion in pipe. The defoaming efficiency and the pressure drop is the screen in addition to the two important performance indicators. The eliminator performance of wire mist eliminators are still relatively small. Some researchers obtained through experiments in a semi empirical formula of foam efficiency and pressure drop, and a few researchers have calculated the effective model of wire network in addition to Mo performance by CFD simulation in this paper. The use of porous media and two kinds of matrix model staggered mesh demister model, and analyzes the factors affecting the performance of the screen. In addition to the performance of Mo Mo screen has practical significance for engineering application, first demister The performance has great influence on the total heat transfer area of the seawater desalination device, and the capital cost of the plant has a direct connection. Secondly, in addition to the impact of product performance will be water eliminator, which also relates to the operating costs of the factory. In addition, this paper has certain innovation, help to further study the guidance performance of the screen eliminator. The main research contents of this paper are as follows:
1. will be the first wire mesh demister is assumed to be porous media, discusses the gas flow rate, wire diameter, packing density of dry pressure drop.
2. using the alternate matrix model for different structural parameters and operating conditions in the internal flow field of screen entrainment was simulated to obtain mesh collection efficiency and pressure gradient, which can calculate the screen of demister efficiency and pressure drop of wire mesh demister mesh diameter, filling rate, thickness of effect of defoaming efficiency, as well as the relationship between the Stokes number and wire collection efficiency. In addition, the introduction of demister quality to evaluate the performance of the different structure of entrainment.
3. based on response surface method, analysis software Design-Expert obtained the defoaming efficiency by using statistics, pressure drop and demister quality prediction model, and according to the response surface and contour map of the interaction between factors is analyzed and evaluated. The prediction model can intuitively reflect the screen except structural parameters and operating conditions of the eliminator. In addition to the performance effects of entrainment, and contribute to the optimization design of wire mesh demister.

【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P747

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