【作者】 张亚竹；

【导师】 李保卫； 赵增武；

【作者基本信息】 内蒙古科技大学 ， 热能工程， 2008， 硕士

【摘要】 平焰燃烧是近代发展起来的技术,具有加热均匀、覆盖面积广、污染小等特点,在工业加热领域得到了广泛应用,其燃烧火焰结构与流动特性研究对进一步优化燃烧器结构有着重要的意义。早期火焰流动研究一般建立在冷态实验的基础上,随着对燃烧流场研究的不断深入,利用冷态实验来模拟燃烧状况已不能满足研究的要求,需要对燃烧流场直接进行测量。燃烧火焰可视化技术成为解决这一问题的一个重要途径,PIV(粒子成像测速技术)的应用是较为成熟的主要研究方法之一,克服了以往单点测速技术的局限性,实现了对流场的瞬态、全场的定量测量。本文采用PIV方法进行了平焰燃烧流场的研究。首先,设计并建立了扩散火焰实验台,初步实现了火焰内部的流动可视化。并自行设计了供粉均匀、速率可控的粒子供粉器,探索并掌握了燃烧流场PIV测试方法与参数,并对扩散火焰反应流场和无反应流场进行了比较,研究了不同形状稳焰器对燃烧火焰的影响。其次,针对平焰燃烧试验炉燃烧火焰,进行了火焰流场的PIV测试,并分析了平焰燃烧火焰结构特征,相对于无反应流,平焰有反应流的附壁射流区厚度薄,中心回流区半径大。对于扩散型火焰,反应流和无反应流径向速度的曲线相近,类似于抛物线形,对于轴向的速度,无反应流的轴向速度衰减快,而反应流的轴向速度基本没有明显的衰减;加60mm的圆盘和60mm的V型稳焰器火焰的稳定效果要优于不加圆盘、或加20mm和40mm的圆盘和V型稳焰器;对于平焰来说,在实际的燃烧过程中附壁射流区的厚度变薄,半径方向和中心回流区逐渐增加;预混的流场比非预混的流场在支持平展流上效果要好;空气过剩系数1.23和1.37的流场效果要优于1.06的流场。本研究对火焰结构与流场认识,燃烧器优化与工业炉窑优化设计等有着重要的指导意义。更多还原

【Abstract】 Flat flame has been used to heat evenly、cover broad、reduce pollutant emission in the field of industrial heating has been widely applied, the flame structure and flow characteristics of the burner further optimize the structure is of important significance . Before, the investigation of combustion can not be directly linked to the corresponding flames, and non-reacting experiment can not satisfy for the needs of research. As an available method for complex phenomena and data field, the technique of visualization has become a hot spot in combustion. Particle Image Velocimetry (PIV), as a newly developed technique in the latest decade, is a non-intrusive measurement means for acquiring velocities and related properties in fluids through analyzing the correlation of flow field images, avoiding the drawback of the intrusive single-point measurement apparatus.In this paper, experimental study on velocity flow fields of flat flame by PIV. Firstly, designed and established the diffusion flame test-bed、designed a seeder particles power device for uniform for the powder controllable rate for the powder particles, to explore and master the methods and parameters of combustion flow PIV testing, and compared with differences between reacting and non-reacting flow fields. It studied the effect of different velocity stream distributions for two varying stability of the flame devices outer flow of the burner. Secondly, testing and analysis flat flame flow field by PIV testing of the flat flame characteristics, the heat release from combustion enhanced the inner recirculation zone by increasing its width and length. Combustion enhanced significant increase in velocity magnitudes than that for the no combustion.According to experimental results from two kinds of flame types with or without reacting by PIV, the major findings are as follows: for diffusion flame, 60 mm disk and V-steady flame equipment are better than other flame equipments. For flat flame, in the actual combustion process, the thickness of wall-attached jet is thinner, and both the radius and the circumfluence velocity of central circumfluence zone are increased compared with test results of non-reacting flow;Premixed flow is much greater than non-premixed flow in support of flat effect;Excess air ratio of 1.23 and 1.37 are effective to flow field than the one of 1.06.Thus this reach provides insightful information on the flame flow field dynamics in complex swirl flow fields in addition to combustion optimization and optimal design guiding significance.更多还原