【作者】 范文武；

【导师】 丘纪华；

【作者基本信息】 华中科技大学 ， 热能工程， 2007， 硕士

【摘要】 电力工业是国民经济发展中最重要的基础能源产业,而我国的发电以燃烧化石燃料为主。随电力行业的发展,煤炭的消耗量在未来较长的一段时间内将持续走高,NO_X排放量也会逐渐增加。NO_X的生成会对生态环境造成严重的破坏。因此,控制NO_X的排放是我国迫在眉睫的问题。NO_X的生成机理分为:燃料型、热力型和瞬时型。根据NO_X的生成机理,国外开发出了多种低NO_X燃烧技术。由于国内煤质特殊情况,燃烧器不仅要能有效的抑制NO_X的生成,还要能保证煤粉着火和燃烧的需要。因此,在借鉴国外先进的技术上,国内近年来研发了多种符合本国国情的低NO_X燃烧器。但是由于煤粉燃烧过程中NO_X生成的复杂性,低NO_X燃烧器还有待进一步的研究发展。本文研发了一种新型低NO_X燃烧器。通过对回流区火焰稳定性和NO_X的生成进行分析,在钝体燃烧器上添加燃烧齿。由于钝体和燃烧齿的存在,流体经过时形成回流区,增加煤粉燃烧的稳定性,并且在燃烧齿后风粉形成浓淡分离,有助于降低NO_X的排放。根据此原理,遵从相似三大定理,对燃烧器的结构、大小、钝体类型和燃烧齿大小做出优化考虑,从而构成单口燃烧器。根据燃烧器的特性,提出三种不同类型的燃烧齿进行冷态试验,对其后出口流场特性进行分析和回流区大小的测定,并进行类比分析。试验表明,对应不同的燃烧齿其后的速度流场和回流区大小形状不同。当燃烧齿与钝体间的流量和燃烧齿之间的流量相当时,燃烧齿和钝体其后的回流面积将有一最佳值。其次,当燃烧齿高度已定,长度越大或倾斜角度越小时,射流刚性越强,整个回流区的体积高度逐渐减小,宽度逐渐增大,长度略微加长。因此,可根据实际煤种情况来确定燃烧齿的类型。更多还原

【Abstract】 The electric power industry is the most important foundation of energy industry in the national economy development, but the generate electricity of our country take burning the fossil fuel as the lord. With the development of the electric power industry, the depletion quantity of the coal will keep on to rise in longer period of time of future high, and the NO_X exhaust quantity also will increase gradually. NO_X of formation will result in the serious breakage to the ecosystem environment. Therefore, control of NO_X exhaust is the utmost urgent problem to our country.The NO_X formation mechanism is divided into: Fuel NO_X, Thermal NO_X and Prompt NO_X. According to the NO_X formation mechanism, the abroad studied various low NO_X’s combustion technique. Because of the characteristic of local coal quality, the burner not only can control the NO_X effectively formation, but also can guarantee that pulverized coal steadily catch fire. Therefore, in drawing lessons from the abroad advanced technique, the domestic expert studies the various low NO_X burner of the native state in recent years. But formation complexity of NO_X in the pulverized coal combustion process, the low NO_X burner still needs the further research development.This thesis studied a kind of new low NO_X burner. Through analyzing the flame stability of back-flow region and NO_X formation, the burnable saw-teethes are added on the V-shape bluff burner. Because of the existence of the V-shape bluff body and burnable saw-teethes, pulverized coal steadily catch fire for formation of the back-flow region and NO_X exhaust also will be reduced for rich and lean separation technique. Therefore, the low NO_X burner is successfully devised by the three greatest likeness theorems. According to the characteristic of the burner, the three kinds burnable saw-teethes carry on cold-state experiment, and author compare to analyze spout characteristic of aerodynamic field and size of back-flow region. Experiment indicated that the different burnable saw-teethes have the different speed flow fields and different sizes of the backflow region. When the flux between the burnable saw-teethe and the V-shape bluff equal to it of burnable saw-teethes, back-flow region area has the biggest value. Secondly, when the height of burnable saw-teethe have already been fixed, more length or smaller inclined angle, jet rigidity will be stronger and volume of back-flow region will be larger. Therefore, according to the actual coal, we can choose to the certain burnable saw-teeth.更多还原