蒸汽喷射器理论及数值模拟分析

发布时间：2018-01-03 21:38

本文关键词：蒸汽喷射器理论及数值模拟分析　出处：《东北大学》2013年硕士论文　论文类型：学位论文

【摘要】：喷射器是提高流体压力而不直接消耗机械能的设备,因其结构简单可靠、运转费用低廉而得到广泛应用。然而,喷射器效率低下,不节能,如何提高其效率是大家共同关心的问题。目前喷射器的设计一般是根据工作参数来确定具体的结构,采用的计算公式多为一维等熵假设基础上的半经验公式。而针对喷射器内复杂流场的实验观察、分析模拟,以及喷射器结构对喷射器性能影响等具体细节的研究方面,由于受实验水平、计算能力、流体力学理论发展水平的限制,是不充分的。尤其是对以蒸汽为工质的喷射器,由于蒸汽的物性远离理想气体状态,让简单的采用理想气体状态方程所得出的结果与实际偏离很大。本文依据索科洛夫喷射器的设计理论,假设定压混合,利用VC语言编制了喷射器喷射系数的计算程序,并辅之以经验公式,得到了喷射器结构的设计尺寸。采用FLUENT软件对蒸汽喷射器内流体的混合过程进行数值模拟。分析了湍流模型、离散格式等因素对数值计算结果的影响,以期获得网格收敛的解。通过观察喷射器的内部流场云图,可以了解其内部的流动过程和工作原理。通过改变喷射器的结构参数,得出喷射系数随结构参数的变化规律；通过改变工作参数,分析喷射系数随工作参数的变化情况。
[Abstract]:Ejector is a kind of equipment which can increase fluid pressure without directly consuming mechanical energy. It is widely used because of its simple and reliable structure and low operating cost. However, the injector is inefficient and does not save energy. How to improve its efficiency is a common concern. At present, the design of ejector is usually based on the working parameters to determine the specific structure. Most of the formulas used are semi-empirical formulas based on the one-dimensional Isentropic hypothesis, and the simulation is analyzed for the experimental observation of the complex flow field in the ejector. As well as the effect of ejector structure on the performance of ejector, due to the experimental level, computational power, fluid dynamics theory development level limited. Is not sufficient, especially for ejectors with steam as the working fluid, because the physical properties of the steam are far from the ideal gas state. In this paper, according to the design theory of Sokolov ejector, the constant pressure mixing is assumed. The calculation program of ejector injection coefficient is compiled with VC language, and the empirical formula is used. The design size of the ejector structure was obtained. The mixing process of the steam ejector was numerically simulated by FLUENT software. The turbulence model was analyzed. In order to obtain the solution of mesh convergence, the effect of discrete scheme and other factors on the numerical results is obtained, and the cloud diagram of the internal flow field of the ejector is observed. The internal flow process and working principle can be understood. By changing the structural parameters of the ejector, the variation law of the jet coefficient with the structural parameters can be obtained. By changing the working parameters, the variation of the injection coefficient with the working parameters is analyzed.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH122

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