Effect of variation of inlet boundary conditions on the combustion flow-field of a typical double cavity scramjet combustor

The present research work deals with the numerical simulation of double cavity scramjet combustor by using two equation standard k-$\epsilon$ turbulence model and finite-rate/eddy-dissipation reaction models which is again coupled with Reynolds-Averaged Navier-Stokes (RANS) equations to investigate the influence of variation of inlet boundary condition of air as well as H₂ fuel on the combustion flow-field of scramjet engine subsequently. At the same time, the validations of the current computational approach have been completed against a standard experimental data which is available in the literature. An acceptable similarity is observed between present numerical approach with the experimentally attained schlieren photograph and the pressure distribution curve. In the present work, 8 different cases are studied. Among them, first four cases are investigated for the variation of inlet boundary condition of air and the remaining four cases are studied for the variation of inlet boundary condition of H₂ fuel. The obtained results show that the formation of high-pressure region around the cavities for case 3 and case 4 actually helps to push the greater amount of air to the cavity region where it is mixed with adequate amount of H₂ for proper and stable combustion whereas for case 6, it is observed that most of the combustion phenomena closely fitted into a small space of the combustor and mainly occurs near the cavity region.     

大功率氧煤燃烧器内冷态流场试验研究

研究热风管中不同结构的氧煤枪出口下游冷态两相流场。提出高炉炼铁大功率氧煤燃烧器新型结构。用流场显示，热球风速仪，三孔探针和取样探针给出其中时均速度场、回流区大小、位置及颗粒浓度分布。冷态试验结果表明：大口径同轴射流渐扩式大功率氧煤燃烧器在加强氧煤混合，增长煤粉停留时间，强化枪体冷却。延长使用寿命上会有好的效果。为实现提高大喷煤量气化率的热态试验和结构优选提供了依据。     

The Industrial Biomass Combustor Design for Producing Heat in Dried Tuna Fish Production of Halla Food Factory

The industrial biomass combustor of Halla food factory in Thailand was designed for drying tuna fish product. The purpose of this paper needed to present the design of a factory combustor for producing heat in the drying process by thermal energy from biomass fuel combustion to reduce the investment cost. A drying chamber was made from four concrete walls in the rectangular volume of 4.7 × 4.7 × 2.5 m3 for drying tuna fishes that sliced to small pieces of around 2,680 kg fresh tuna. The hot air tube in the combustor was used for driving hot air to dry fishes in the drying chamber. Heat from acacia wood burning in the combustor with the consumption rate of 50.1 kg/h was transferred by the hot air. The design result was calculated for thermal energy and the efficiency of around 200 kW, and 32%, respectively in the case of 0.62 m3/s hot air flow rate that circulation between the combustor and the drying chamber. The experimental result shows that the moister content of 78.9%wb was decreased to around 13.8%wb in 5 days without petroleum fuel. The drying temperature was controlled at 70℃ continuously for reducing hard containing, and the closed loop tube design for the less of BaP （benzo （a） pyrene） from combustion smoking of the drying industrial process.     

Rijke燃烧装置中热源位置的数学模型

根据Ｒａｙｌｅｉｇｈ准则建立了一个简化的数学模型,对Ｒｉｊｋｅ燃烧装置中热源的特性位置进行了研究,避免了线性化分析方法的不足,同时将理论分析的结论和实验结果进行对比,得出Ｒｉｊｋｅ燃煤装置的热源相对高度可取０．１２～０．１３,能够发生声波作用下的燃烧。图３表１参５     

新型Rijke管燃烧装置特性分析

在实验的基础上指出,声脉动的发生不仅取决于Ｒｉｊｋｅ燃烧器的结构及热源位置,还受到进口处空气流速、温度梯度和气体平均密度等参数的影响。当这些参数和脉动速度数量级相当时,稳定的声场强度随空气进口流速的增大而加强,该流速的确定同时还要考虑燃烧的完全性。维持一个稳定的声波作用工况必须满足对热源强度与位置特性的要求以及燃烧器进口空气流场分布均匀性的要求。     

电站煤粉锅炉无油点火技术分析

就目前电站锅炉使用的几种无油点火方式及其特点进行了详细地分析,在此基础上提出了利用中频感应加热高温空气煤粉直燃技术方案,并进行了高温空气煤粉点火系统的实验研究,为高温空气煤粉点火燃烧器的优化设计奠定了坚实的实验基础。所开发的新型点火装置,具有启动迅速、防结焦性能优越、污染排放少等特点,完全满足环保和工程应用的要求。     

Rijke型燃烧装置结构特性对声波自激的影响

分析了 Rijke型燃烧器结构对声波产生的影响 ,根据理论分析及实验结果得出在较大型化的实验装置上实现声波作用燃烧的可能性和燃烧器结构对声激发的影响规律 ,以及减少燃烧器内部声能损失 ,促进和维持声能自激、转换的方法 ,为 Rijke型燃烧器走向大型化、实用化提供了理论及实验依据。     

重型燃气轮机先进低NOx燃烧技术分析

对重型燃气轮机领域中的低NOx燃烧技术进行介绍与说明,首先简要论述了重型燃气轮机燃烧室中氮氧化物的产生机理及抑制方法,其次,介绍了贫预混多喷嘴分级燃烧技术、富油/烽熄/贫油燃烧技术和贫预混低旋流燃烧技术等7种可用于重型燃气轮机燃烧室的先进低NOx燃烧技术,并详细论述了这7种低NOx燃烧技术的作用原理及应用进展,可为国内重型燃气轮机低污染燃烧室的设计与研制提供技术参考.     

废碱焚烧装置燃烧器自控系统节能效果探讨

针对废碱焚烧装置的炉膛结构特点及燃烧状况,设计了一套燃烧器自动控制系统;对燃烧器进行合理的分组控制,分析了控制原理,编制了控制电路图及程序流程图等,并对其能达到的节能效果进行了分析。     

采用热-流耦合方法对火焰筒壁温三维数值模拟

考虑了流场变化对换热的影响,使用热-流耦合方法,对某型燃烧室整个流场、温度场进行完全的数值模拟。该方法对流场和固壁内换热进行耦合计算,得出了三维燃烧室壁温分布。计算中,对完全发展的湍流燃气采用了标准“k-ε”湍流模型,运用DO模型计算了燃气的热辐射,燃烧模型使用涡-耗散模型来计算化学反应速度,固壁材料使用了变比热和变导热系数。数值模拟结果表明流场与固壁相互作用得更充分,能更精确地反映流场和温度场的整个形态,可以模拟出较为合理的流场和温度场分布以及相应的流动换热特性。