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本文对带有隔热屏、外冷却通道和稳定器的加力燃烧室的热态流场了数值模拟。加力燃烧室中的网格划分采用了非均匀交错网络系统,应用SIMPLE算法来求解各守恒方程。采用了双方程k-ε紊流模型来预估紊流特性;采用简单的单步化学反应假设的k-ε-g紊流燃烧模型描述紊流燃烧;采用热通量法辐射模型来估算辐射通量和壁面温度。另外还研究了在加力燃烧室外冷却气流对加气燃烧室筒体壁面进行冷却后壁温分布情况,以及V型稳定器 相似文献
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本文针对某燃气轮机环管型燃烧室三维冷态流场的数值模拟问题进行了研究。根据该型燃气轮机燃烧室的设计图纸建立真实的三维计算几何模型;在计算中采用SIMPLE算法,k-ε双方程湍流模型,对其进行了冷态空气流场的数值模拟;通过对各处流场分布的分析,特别是对主要区域各关键截面的流动分析,可以判断出燃烧室设计的合理性,为进一步优化燃烧室的结构设计、改善流场结构,并为开展燃烧室热态流场的数值模拟奠定了基础。 相似文献
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对燃气轮机逆流式环形燃烧室,热态三维流场的数值模拟问题进行了研究,建立了三维计算模型,生成了数值计算网格。数值模拟研究表明,改变燃烧室的几个结构参数,可以得到更加合理的流场。通过对关键截面的流动分析,可以判断燃烧室设计的合理性,为进一步优化燃烧室结构设计、改善流场奠定了基础。 相似文献
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柴油机燃烧室的设计,通常以经验设计为主,要通过实机实验,比较得到较优燃烧室形状,周期长,费用高。本文通过模拟不同形状燃烧室内的三维流场,分析缸内气流运动规律,评述了不同燃烧室形状的优缺点。 相似文献
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某型燃气轮机燃烧室性能数值模拟 总被引:1,自引:0,他引:1
应用CFD方法对航改QD128燃气轮机燃烧室性能进行了数值模拟。模拟结果表明:燃烧室流量分配设计基本合理,燃烧室内流场分布符合设计规律;燃烧室出口平均温度为1 298K,热点温度1 486K,径向温度分布曲线符合设计要求,OTDF=0.280,RTDF=0.086,略高于航机水平。模拟结果丰富了QD128燃机性能指标,为该机的运行、改进提供了可靠的参考依据。 相似文献
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炉膛(CFS系统)燃烧过程的数值模拟及工程应用 总被引:6,自引:0,他引:6
本文以某厂四角燃煤锅炉为例,进行一、二次风同心正反切时炉内冷、热态试验研究,并进行数值模拟与之对照。试验和数值模拟结果均表明:当一、二次风气流以一定角度交叉送入炉膛时,合理调节一、二次风气流配风角度,采用合适的一、二次风动量矩的比值,能够改善炉内空气动力结构,减少煤粉气流刷墙贴壁,有利于防止燃烧器区结渣。 相似文献
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以CFD软件为计算平台,数值模拟研究1105型直喷式柴油机不同喷束夹角的燃烧过程,预测了喷束夹角变化对动力性能和排放性能的影响。结论显示:喷束夹角减小,可以提高缸内平均压力和平均温度,改善燃烧室内温度场分布,但同时使NOx和CO的排放增加。因此,喷束夹角的选择需要均衡柴油机动力性和排放性两方面的因素。 相似文献
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S. Eiamsa-ard Y. Kaewkohkiat C. Thianpong P. Promvonge 《International Communications in Heat and Mass Transfer》2008
The combustion characteristics of rice husk fuel in a dual-staging vortex-combustor (DSVC) are experimentally investigated. In the present work, the vortex flow is created by using a snail entrance mounted at the bottom of the combustor. The temperature distributions at selected locations inside the combustor, the flue gas emissions (CO, CO2, O2, NOx), and the combustion/thermal efficiency are monitored. Measurements are made at a constant rice husk feed rate of 0.25 kg/min with various excess airs (37%, 56%, 74% and 92%) and different secondary air injection fractions (λ = 0.0, 0.15 and 0.2), respectively. The combustion chamber is 1800 mm high and 300 mm in diameter (D) with a centered exhausted pipe while the middle chamber of the combustor is set to 0.5D. The smaller section at the middle chamber is introduced to split the chamber to be dual-staging chamber where a large central toroidal recirculation zone induced by swirl flow through the small section is generated in the top chamber. The experimental results reveal that the highest temperature inside the combustor is about 1000 °C whereas both the thermal and the combustion efficiency are 41.6% and 99.8% for 74% excess air without the secondary air injection (λ = 0.0). In addition, the emissions are CO2 = 8.1%, O2 = 9.3%, CO = 352 ppm, NOx = 294 ppm and small amount of fly ash. Therefore, the DSVC shows an excellent performance, low emissions, high stabilization and ease of operation in firing the rice husk. 相似文献
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《International Journal of Hydrogen Energy》2023,48(11):4503-4515
The paper reports on the results of an experimental study of methane and syngas combustion as well as their co-firing in a bidirectional swirling flow. The results confirmed that the bidirectional flow structure provides a significant decrease in the lean blow-off equivalence ratio as well as that of emissions of main pollutants. The combustion intensification becomes more evident when using syngas is as fuel. The composition of the used syngas is as follows (by volume): H2 - 29.42%; CO - 14.32%; CH4 - 3.8%; N2 - 49.11%; H2O - 3.35%. In this case, the lean blow-off is achieved at ? < 0.1, NOx emission is halved, while CxHy and CO emissions become 20 times less compared to pure methane combustion. However, according to experimental results, the co-combustion of syngas (volume fraction Vsyn = 15%) and methane is the most appropriate fuel utilization mode. It provides blow-off and emission properties similar to those for combustion of pure syngas, whereas energy consumption for its production is much lower. Moreover, unlike hydrocarbon fuel combustion, that of syngas in a bidirectional swirling flow is characterized by the presence of density stratification. This is accompanied by the flame formation at significantly different locations in the combustion chamber at lean and “ultra-lean” modes of operation. Hydrogen combustion most likely to occur in the core region at near-blow-off modes ? < 0.1, whereas normal ‘operating modes in the range 0.2 = ? ≤ 0.4 result in the formation of a conical flame surface where CH4 and CO combustion occurs. These new results with respect to the flame structure as well as blow-off and emission properties make it possible to consider bidirectional vortex combustors for application in modern gas turbine power plants in order to meet the strict environmental and energy requirements. 相似文献
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本文根据柴油机燃烧过程的数学模型,将Chemkin中甲醇燃烧动力学反应机理导入Fluent软件中,对各种比例下的甲醇柴油微乳液进行了燃烧模拟计算,并用S195柴油机在台架上对计算值进行测试验证。结果表明:数值模拟的方法可靠。在不改动柴油机结构的情况下,甲醇含量影响燃烧效果,低甲醇含量可以提高燃烧效率,高甲醇含量降低燃烧效率,甲醇含量为10%时最佳。 相似文献
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溶有CO2燃油发动机燃烧的数值研究 总被引:4,自引:1,他引:4
在KIVA程序的基础上修改了油滴的蒸发模型,并根据实测数据对溶有CO2的燃油在缸内的喷射、蒸发、燃烧过程进行了数值模拟,计算结果表明,溶有CO2的燃油喷射可有效地降低燃烧初期油束区的温度和氧浓度,从而降低燃烧温度,减少NOx的生成。 相似文献
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《能源学会志》2014,87(4):372-382
Recent technologies have been introduced for gas turbine engine to meet with stringent emission regulations. One of the technologies is to introduce recirculation in the combustion zone to control the residence time and mixing by help of swirling flow. Effect of variation in geometric parameters and inlet mass flow of swirler have been examined in this study by help of CFD. Detailed design methodologies have been proposed in this study to design a series of axial swirler with different vane angles and vane numbers. Substantial variation in swirler performance has been observed by changing vane angle, vane number and mass flow. Four different types of axial and radial velocity profiles have been observed. Turbulence distribution pattern shows double peaks at all positions and reduces with increasing axial distance. 相似文献
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燃烧室形状对柴油机性能影响的研究 总被引:1,自引:0,他引:1
为研究混合气的形成状况和燃烧质量,探索燃烧室形状对柴油机性能的影响,本文应用STAR—CD程序对不同几何形状的燃烧室内的燃油雾化、燃烧进行三雏数值模拟。计算结果表明,燃烧室的形状对燃烧过程有着重要影响。缩口燃烧室具有较大的挤流强度,较长的涡流持续期,较合理的涡流分布,更有利于混合气的形成,可以进一步加速扩散燃烧,产生较高的缸内压力和温度,具有最好的燃烧性能。直口燃烧室燃烧性能相对较差,敞口燃烧室的最差。但是缩口燃烧室的热应力较大,残余废气不易排除,实现增压比较困难。 相似文献
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内燃机排气消声系统声学特性的数值预测 总被引:2,自引:0,他引:2
提出了一种有效预测内燃机排气消声系统声学特性的新方法。此方法使用传递矩阵法和边界元法计算整个排气水声系统的四极参数,使用双负载法和特征线法确定发动机的声源阻抗和强度,实现内燃机排气噪声插入损失预测。文中对一台柴油机排气消声系统进行了研究,其预测结果与实测结果吻合良好。 相似文献