多组分燃气旋流预混合燃烧特性研究

发布时间：2018-09-05 13:04

【摘要】：低旋流燃烧(简称LSC)技术是一种背离传统回流稳焰机理的燃烧方式,利用低旋转扩散无回流湍流流动方式稳定自由传播湍流火焰。低旋流喷嘴(LSI)具有结构简单、成本低廉、易于适配现有燃机、NO_x排放低等特点。因此,对低旋流燃烧的研究具有重要的应用价值和学术意义。本文自行设计了燃烧室腔体并加装在燃烧实验台上,使用丙烷、甲烷以及掺氢甲烷混合气作为燃料。通过更换低旋流喷嘴中心孔板来改变旋流器的旋流数,主要使用的旋流数为S=0.521、0.545、0.575、0.623。本文中分别使用光谱仪对低旋流贫预混燃烧的火焰频谱进行测量;使用Canon EOS 7D相机对低旋流贫预混燃烧的火焰形态进行拍摄;使用B型双铂铑热电偶对低旋流贫预混燃烧的火焰轴向和径向温度进行测量;使用便携式烟气分析仪对低旋流贫预混燃烧的火焰污染物排放进行测量。得出以下结论:(1)甲烷、掺氢甲烷混合气燃烧过程中随着旋流数S的增加,OH和CH自由基的相对能量值随之减小。(2)蓝色火焰由"W"型变成扫帚型,随着旋流数的增加火焰前缘和喷口的距离缩短。随着燃料C-H比的减小,火焰的颜色明显变淡。在甲烷中掺混氢气后,火焰长度也会随之缩短。(3)在蓝色火焰温度轮廓峰值的两侧存在高温区。随着旋流数增加,高温区变窄并且蓝色火焰温度轮廓线两侧温度梯度变陡。在旋流数大于一定数值时(临界旋流数S_0在0.575-0.598之间),火焰上端温度会由双峰型变为抛物线型。(4)随着旋流数S的增加,低旋流火焰中心径向温度逐渐降低。(5)LSI的NO_x和CO的排放水平主要取决于气体的组分和热负荷。随着旋流数S的增加,低旋流火焰的EI_(NO_x)随之增大。(6)在相同工况条件下,低旋流火焰的燃烧效率高于高旋流火焰。
[Abstract]:Low swirl combustion (LSC) technology is a kind of combustion mode which deviates from the traditional reflux flame stabilization mechanism and uses the low rotation diffusion non-reflux turbulent flow to stabilize the free-propagating turbulent flame. Low swirl nozzle (LSI) has the advantages of simple structure, low cost and easy to adapt to the existing gas turbine, such as low Nox emission. Therefore, the study of low swirl combustion has important application value and academic significance. In this paper, the combustion chamber is designed and installed on the combustion test bench. The mixture of propane, methane and hydrogen methane is used as fuel. The swirl number of the cyclone is changed by replacing the central orifice plate of the low swirl nozzle. The main swirl number used is S0. 521 0. 545U 0. 575N 0.623. In this paper, the flame spectrum of low swirl lean premixed combustion was measured by spectrometer, and the flame morphology of low swirl lean premixed combustion was photographed by Canon EOS 7D camera. The flame axial and radial temperatures of low swirl lean premixed combustion were measured by B type double platinum rhodium thermocouple, and the emission of flame pollutants from low swirl lean premixed combustion was measured by portable flue gas analyzer. The following conclusions are obtained: (1) the relative energy values of OH and CH radicals decrease with the increase of swirl number S during the combustion of methane mixed with hydrogen. (2) the blue flame changes from "W" to "broom". With the increase of swirl number, the distance between flame leading edge and nozzle is shortened. With the decrease of C H ratio of fuel, the color of the flame becomes lighter obviously. The flame length will also be shortened after mixing hydrogen in methane. (3) there is a high temperature region on both sides of the blue flame temperature profile. With the increase of swirl number, the high temperature region becomes narrower and the temperature gradient on both sides of the blue flame temperature profile becomes steeper. When the swirl number is greater than a certain value (critical swirl number S0 is between 0.575-0.598), the temperature at the top of the flame will change from bimodal to parabolic. (4) with the increase of swirl number S, The radial temperature of low swirl flame center decreases gradually. (5) the emission levels of NO_x and CO of LSI mainly depend on the gas composition and heat load. With the increase of swirl number S, the EI_ (NO_x) of low swirl flame increases. (6) under the same condition, the combustion efficiency of low swirl flame is higher than that of high swirl flame.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK16

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