一种高效多孔介质燃烧器模型建立及其燃烧数值模拟

发布时间：2018-04-27 03:39

本文选题：节能减排 + 多孔介质材料　；参考：《湖南科技大学》2015年硕士论文

【摘要】：在当下,我国的能源利用现状存在着不容忽视的问题：效率低下、环境污染、产能过剩、浪费严重……并且,大量工业开发的低品位能源未被有效利用。如低浓度瓦斯,在常规燃烧设备上难以被安全有效使用,直接排入大气又会造成环境污染和能源浪费。节能减排,实现能源的高效合理利用,达到经济增长和环境保护的“双赢”,是关系我国长远发展的重要战略问题。因此,许多有利于环境保护和节约能源的新燃烧技术应运而生,其中具有优越特性的多孔介质燃烧技术应用前景十分光明。多孔介质材料具有蓄热能力强、导热和辐射性能优良、抑制爆燃等诸多优点,在多孔介质燃烧系统中,热输运方式主要是通过固体导热和固体辐射传热,以此将燃烧反应发生区域的大量热量输送到反应区前,使未燃气体得到预热,因此和传统的燃烧器相比,多孔介质燃烧器可以使气体燃料燃烧更加充分,提高燃烧效率,扩展贫燃极限,体积分数极低(低于35%)的可燃气体可以在多孔介质燃烧器内燃烧,并且污染物排放量较低。近些年来国内外燃烧和工程热物理界的专家学者予以多孔介质燃烧技术高度关注。本文首先对比优选燃烧模拟软件,选择FLUENT软件作为多孔介质燃烧器模拟软件；基于瓦斯燃烧基本规律分析甲烷／空气预混气体在多孔介质内燃烧的机制,结合多孔介质燃烧器应用现状、国内外多孔介质燃烧实验和数值模拟现状,本着加强燃烧器对预混气体燃料的预热作用、使燃烧更成分的目的,对目前工业应用和研究采用的两段式多孔介质燃烧器进行了结构上的改进；对比在不同当量比和入口流速下新燃烧器和改进前的燃烧器的燃烧性能,开展贫燃料燃烧模拟,关注火焰面运移规律,并考察了新燃烧器中主要污染物NOx的排放情况；同时还借助数值模拟考查了多孔介质材料一些物性参数的改变对燃烧效果的影响。研究得到,改进后的新燃烧器可以实现燃烧温度更高、节约燃料、贫燃瓦斯气体利用率提高的目的。合理选择搭配多孔介质材料,也可以进一步提高燃烧效率。本研究为多孔介质燃烧装置的工业开发与应用提供了新的思路与方向。
[Abstract]:At present, the current situation of energy utilization in China can not be ignored: inefficient, environmental pollution, overcapacity, serious waste. Moreover, a large number of industrial development of low-grade energy has not been effectively used. If the gas concentration is low, it is difficult to be safely and effectively used in the conventional combustion equipment, which will lead to environmental pollution and energy waste. Energy saving and emission reduction, efficient and rational utilization of energy, and "win-win" of economic growth and environmental protection are important strategic issues related to the long-term development of our country. Therefore, many new combustion technologies have emerged in favor of environmental protection and energy conservation, among which the application prospect of porous media combustion technology with superior characteristics is very bright. Porous media materials have many advantages, such as strong heat storage ability, excellent thermal conductivity and radiation performance, suppression of deflagration and so on. In the combustion system of porous media, heat transfer is mainly through solid heat conduction and solid radiation heat transfer. In this way, a large amount of heat from the combustion reaction area is transferred to the reaction area, which makes the unfired gas body preheat. Therefore, compared with the traditional burner, the porous media burner can make the gas fuel burn more fully and improve the combustion efficiency. The combustible gas with very low volume fraction (less than 35%) can be burned in the porous media burner and the pollutant emission is low. In recent years, experts and scholars in the field of combustion and engineering thermal physics at home and abroad have paid close attention to the combustion technology of porous media. In this paper, FLUENT software is chosen as the simulation software of porous media burner, and the mechanism of methane / air premixed gas combustion in porous media is analyzed based on the basic law of gas combustion. Combined with the present situation of the application of porous media burners, the combustion experiments and numerical simulation of porous media at home and abroad, in order to strengthen the preheating effect of the burners on premixed gas fuels, the combustion is more combustible. The structural improvement of the two-stage porous media burner used in industrial application and research is carried out, and the combustion performance of the new burner under different equivalent ratio and inlet velocity is compared with that of the burner before the improvement, and the lean fuel combustion simulation is carried out. The flow law of flame surface was concerned, and the emission of NOx, the main pollutant in the new burner, was investigated, and the influence of some physical parameters of porous media on the combustion efficiency was also investigated by numerical simulation. The results show that the new burner can achieve higher combustion temperature, save fuel and increase the utilization rate of lean gas. The combustion efficiency can also be further improved by reasonable selection of porous media materials. This study provides a new idea and direction for the industrial development and application of porous media combustion device.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ052.7

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