共查询到18条相似文献,搜索用时 186 毫秒
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《工程热物理学报》2016,(11)
采用NH3模拟燃料氮,数值预测了Ar稀释的CH_4/空气对冲扩散火焰在不同压力下NO的生成,并讨论了燃料型NO生成量的影响因素。结果表明:随着燃料氮含量的增加,燃料型NO反应路径逐渐成为NO生成的主要路径。其生成量随着压力的增加而减少。燃料中CH_4含量和气流出口速度对燃料型NO均有一定影响。CH基团同时参与NO的生成与还原反应,在本文工况下对NO还原反应影响更大,随着燃料中CH_4含量的增加,NO峰值会略有减小。气体出口速度增加,高温区变小,反应物在高温区的停留时间变短,对NO还原反应影响强于NO生成反应,因此随着出口速度增加,NO峰值略有增加。 相似文献
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多种燃料多级燃烧的燃气热力性质简捷算法 总被引:2,自引:0,他引:2
文献[1]给出了计算烃型燃料C_8H_(16)燃烧产物热力性质的方法,文献[2]把它推广到C-H-O-N′-S类型任意燃料。本文在上述基础上,推出能计算多种任意C-H-O-N′-S类型的气体、液体或固体燃料(含不可燃组分)混烧或多级燃烧后的燃气热力性质的简捷方法。 相似文献
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高温空气低燃气浓度燃烧过程的数值模拟研究 总被引:2,自引:1,他引:1
从工程实际出发,本文提出了高温空气低燃气浓度燃烧新技术,即充分利用烟气余热提高助燃空气温度,提高热能利用率;同时通过优化喷口结构,提高燃气射流速度,使燃气射流在同空气射流混合燃烧前卷吸大量炉内烟气,从而降低燃气射流中的可燃物浓度,进而降低氮氧化物的排放。通过数值模拟研究表明,通过燃气射流速度从24.56m/s提高到55.26m/s,可以降低NOx的排放;当围绕燃气喷口的六个圆形空气喷口改为两个矩形喷口时,燃气射流可从两侧卷吸更多的炉内烟气,形成低燃气浓度燃烧,从而大大降低了NOx的排放。 相似文献
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Portland clinker production consists essentially in the burning of material with defined composition in a rotary kiln at temperatures around 1450 °C. The main fuel used in this process is coal, even though in the last few years the use of alternative fuels has been increasing. Four main minerals are formed, namely, tricalcium and dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite. Along with these main phases, variations in burning conditions of fuels or in the local composition of raw materials can lead to the formation of relatively high amounts of secondary by‐products, which can negatively affect the quality of the final material. Characterization of these by‐products allows not only optimization of the process of clinker production but also the design of special refractory materials for the wall of kilns and preheaters. Being found as particles included in (or alternating to) a hard solid clinker matrix, a detailed characterization of these extra phases could be achieved only via microscopic techniques. In this work, micro‐Raman spectroscopy has been successfully tested as a highly selective method for characterization and localization of included minerals that formed as overlapped crusts deposited on the internal wall of a conventional rotary kiln for cement production, without any manipulation of the sample. Understanding the chronological order of deposition of these overlapped layers is extremely important, as it is the only way to go back up to the production process and to individuate the problem. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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旋流扩散燃烧中旋流数对热NO生成的影响 总被引:4,自引:0,他引:4
本文对旋流扩散燃烧进行了数值模拟,研究旋流数对热NO生成的影响,其中对湍流采用Reynolds应力方程模型,对燃烧采用EBU-Arrhenius模型,对热NO生成采用设定PDF的模型。预报了不同旋流数下轴向和切向的平均和脉动速度、温度和NO浓度,指出随着旋流数的增大,计算得到的出口平均NO浓度首先升高然后下降。这一趋势和本文作者最近的实验结果的趋势一致.随着旋流数的增大,湍流脉动首先下阵然后升高,而进口附近的温度上升,二者综合效果造成上述趋势、因此在实际燃烧器中,完全靠改变族流数来控制NO生成是不现实的。应该采取其他方法来降低NO的生成。 相似文献
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Sy-Chyi Lin James T. Richardson Dan Luss 《Physica C: Superconductivity and its Applications》1996,260(3-4):321-326
Continuous synthesis of YBa2Cu3O6+x superconductor was conducted in a rotary kiln. Dense pellets or loose powder of a stoichiometric mixture of copper, barium peroxide, and yttrium oxide were fed into a heated rotary kiln causing ignition on the whole outer surface followed by an inward movement of a combustion front. Following this thermal explosion, the pellet was post-treated (sintered) at 900 to 985°C as it moved along the kiln, and a product containing about 95 wt% YBa2Cu3O6+x was obtained. The impact of the thermal-explosion temperature, the post-treatment temperature, the pellet density, and the total residence time in the kiln on the product quality were studied. The best thermal-explosion temperature was found to be 800°C, the best post-treatment temperature was 985°C, and the total residence time in the kiln of 100 minutes was sufficient for the pellet to reach equilibrium. 相似文献
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Aiming at the linear temperature compensation algorithm’s disadvantage of temperature measurement error in rotary kiln infrared scanning temperature measurement process, this paper proposes a precise nonlinear cubic polynomial fitting temperature compensation algorithm. The proposed algorithm compensates the temperature values of scanning points on rotary kiln surface by following steps: Calculating temperature difference between the real temperature value of rotary kiln and temperature value measured by infrared scanning temperature measurement system; Fitting the temperature difference data with cubic polynomial; Using the obtained function to compensate temperature. Experimental result shows that compared with the usual linear temperature compensation algorithm, the accuracy of proposed algorithm has raised about 2.25 times when cubic polynomial is used. 相似文献
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1前言NOx是NO煤粉燃烧产生的主要污染物之一,对大气环境的危害十分严重。目前,在降低NO。排放方面,可发展的主要技术有分级燃烧(包括空气分级和燃料分级)、喷氨脱硝、烟气再循环法等。其中,分级燃烧是通过调整燃烧工况来达到低NO。生成量的一种炉内控制技术,一般只需改进燃烧器即可达到,宜优先发展。目前,很多学者在特定的实验条件下对分级燃烧进行了不同角度、不同侧重点的研究,但由于污染物生成机理的复杂性以及燃烧过程化学反应的快速性,对NOx生成的实验研究具有一定的局限性。因此,本文从化学反应动力学的角度,对分级… 相似文献
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