【作者】 张庆洪；

【导师】 张力；

【作者基本信息】 重庆大学 ， 动力工程， 2002， 硕士

【摘要】 文中首先在深入分析国内外燃煤锅炉点火技术及雾化喷嘴的研究现状基础上，首次提出并建立的浙扩切向槽旋流低压燃油喷嘴的物理及三维流动数学模型，采用k-ε/RNG封闭模型，应用SIMPLE数值方法研究切向槽不同渐扩角度对喷嘴内流场的流动特性的技术研究特征，以及优化的结构特征，并经过实验、冷态试验、热态试验表明：渐扩切向槽的偏转角θ对其流动特性影响较大，偏转角θ为负值时，喷嘴出口处回流较大；θ为较大的正值，喷嘴内流体流动越易形成实心的锥体，但其能量损失增加较大；结构特征优化的喷嘴(n=3～4、L≤2.5、θ=2～6°、a/b=1.2和R_x/r_b≥2.5)，在低压下具有良好的雾化特性；优化得到的该喷嘴结构参数是合理的，在低压下(≤1MPa)，可保持良好的雾化质量与刚度，投入煤粉燃烧，燃烧十分良好，有足够的火焰刚度和长度，能在一次风喷口出口2～3米范围内形成完整的火焰，着火和燃烧均很稳定，能达到锅炉开停机和低负荷助燃的目的，运行时的燃油热负荷仅占煤粉喷嘴热负荷的6％～13％，不会引起燃烧器烧坏或结渣，没有热回油，不用雾化介质，能量消耗较小，结构简单实用，雾化流量密度分布均匀，节能省油，运行维护工作量小等显著优点。且节油效果十分明显。将文中研制成功低压燃油喷嘴应用到锅炉点火技术中，无论从安全上、油耗、电耗上都有很大好处，供油泵、管道、阀门及附件的安全系数得到了提高，提高了电厂运行的安全性、可靠性和经济性。 本文开发研制的低压燃油喷嘴与公开的其它燃油喷嘴相比，其工作压力、雾化效果、节油率、射流刚度、燃烧效率、稳定性等性能指标优于国内外公开的其它燃油雾化喷嘴。该旋流雾化喷嘴可广泛用于能源动力、环保、化工及建材等领域的燃烧、烟气除尘与脱硫、均匀加湿等过程。更多还原

【Abstract】 Based on the thorough researching coal boiler ignition and atomized nozzle all of the world, the physical model and its 3-D mathematical model of rotary atomized oil nozzle with micro-expanded tangent channel at low pressure are presented. And then the RNG/k- e model is adopted, and the standard k- e parameters are selected for micro-expanded tangent channel and swirling chamber, the calculated objects are separated from one another with net columns of cross uniform, then limited area equations are decided with control volume method, and the SIMPLE method is used, the flow characteristics and optimum structure parameters are gotten, And the same time, the experiments , tests and industrial application had been made, and the significative results are gotten: The angle( θ) of the micro-expanded tangent channel plays an important role for the fluid characteristics, if θ ≤0, the circumfluence at the exit of the nozzle is obviously, and the 9 >0, the solid cone in nozzle are formed easily, but its energy loss is bigger.The better atomized performance and spraying flow intensity are obtained of this nozzle with optimum structure parameters(n=3~4, L≥2.5, θ=2-6°,a/b=1.2 and Rx/rb>2.5) at low pressure. While the initial pressure po=0.8Mpa, Ux,o=0, Uy,0=0, Uz,0=-0.2m/s,the circumfluence isn’t exactly formed with θ=6 at the exit of the nozzle, and the energy loss is reduced and the atomized angle can get 80 .The many virtues can be acquired while the nozzle has been used in the ignition technology for the coal boiler: (1)The steady flame and combustion can meet the star-up or the lower burden of the boiler.(2)The coke can’t produced on the burner because of the lower heat burden.(3)The lower oil cost and a little maintenance of the equipments are the remarkable feature, etc. And in a word, the security, reliability and economic operation can be obviously improved with the nozzle.The nozzle is widely adequate to the medium atomized instrument about the oil burner and desulphurization & removing dust for coal burning boilers.更多还原