蓄热式钢包烘烤热行为的数值模拟和[NOx]排放特性

为了研究蓄热式钢包烘烤的空气和煤气的预热温度对高温空气燃烧过程的影响,耦合了烘烤过程中流体流动、换热和燃烧过程,用数值模拟方法建立了三维立体数学模型,利用计算流体力学软件Fluent,采用有限元差分法和修正速度—压力相耦合的算法Simple,计算了钢包内的燃烧现象,得出了在不同预热温度时,燃烧室内气体温度场和氧气浓度场的分布。结果表明,提高气体预热温度有利于加快燃烧进程,可提高炉内的整体温度及温度的均匀性,降低局部氧浓度,利用高的烘烤效率减少[NOx]的排放。     

低热值高炉煤气在预热空气作用下的扩散燃烧特性

本研究以某钢铁企业高炉煤气回收水冷系统为对象,分析研究了低热值高炉煤气与不同预热温度空气的同轴扩散气流在绝热炉膛内混合和燃烧的特点,建立了κ-ε双方程燃烧数学模型,并对其同轴扩散气流燃烧特性进行了模拟研究.研究结果表明:空气预热温度的升高能够有效促进化学反应活性较差的CO参与燃烧反应,同时CO化学反应速度也得到有效提高...     

自身预热式燃气辐射管的数值研究

采用 FLUENT商用软件对自身预热式辐射管内的流动、传热和燃烧过程进行了二维数值模拟.研究了内套管与燃烧室出口的相对位置以及助燃空气的一次风与二次风的比例对火焰长度、辐射管温度的影响.结果表明,当增加套管和燃烧室出口的距离时,火焰长度有所增加,辐射管外壁温度、套管平均温度和烟气平均温度有所增加.当增大二次风比例时,火焰长度增加,辐射管外壁温度却减小.计算结果为自身预热式辐射管的开发与优化提供了参考数据.     

高温空气燃烧炉内燃烧特性的数值研究

采用数值模拟法,研究了高温空气燃烧炉内不同空气预热温度、氧气浓度和燃气入口温度对火焰特性和NOx生成和排放的影响规律。研究表明,在提高空气预热温度、降低氧气浓度条件下,在较大范围内进行燃烧,火焰体积变大,炉内温度的峰值相应降低,温度分布更均匀,NOx的生成量大幅度降低。提高燃气入口温度,可抑制燃料和空气在主燃烧区的混合,使火焰内反应物的分布更加均匀,抑制了热力NO的生成,从而减少了NOx的排放量。     

预热温度对热风炉燃烧特性影响的数值模拟

提高风温是高炉炼铁节能降耗的重要技术措施,用CFX模拟不同助燃空气预热温度条件下的燃烧状态,研究结果表明,提高助燃空气预热温度可使燃烧室内的速度场更加均匀,火焰减短,高温区向下扩展,但对燃烧效率没有影响,为迁安2号高炉热风炉实现1 280℃高风温提供理论依据。     

Ԥ���¶ȶ��ȷ�¯ȼ������Ӱ�����ֵģ��

 提高风温是高炉炼铁节能降耗的重要技术措施,本文采用CFX模拟不同助燃空气预热温度条件下的燃烧状态,研究结果表明提高助燃空气预热温度可使燃烧室内的速度场更加均匀,火焰减短,高温区向下扩展,但对燃烧效率没有影响,为迁安2号高炉热风炉实现1280℃高风温提供理论依据。     

套筒式陶瓷燃烧器内燃烧过程数学模型

应用湍流扩散火焰燃烧模型，对套筒式陶瓷燃烧器燃烧室内的燃烧过程进行了计算机模拟研究，确定了燃烧过程中煤气空气及燃烧产物的速度分布，温度２和各组分的浓度分布，得到了燃烧过程中火焰的形状和长度。     

对HTAC燃烧机制下金属镁还原罐内温度分布的数值模拟

简要介绍了HTAC技术和数值模拟方法在燃烧过程研究中的应用。针对HTAC燃烧机制的基本特征,建立了辐射传播数学模型,并运用流体力学软件FLUENT对HTAC燃烧机制下金属镁还原罐内的温度分布进行了数值模拟,研究了HTAC技术的特点,验证了其应用于炼镁生产中的优势。     

外界因素对焊接咬边问题的影响规律

采用Ansys有限元分析法建立了数学模型,分析咬边形成和熔宽最大处熔池的深宽比之间的关系;通过数值模拟方法,分析了工件厚度、工件初始温度以及散热条件对熔池温度场的影响,发现工件厚度较小时不易产生咬边现象,通过提高工件预热温度、改善散热条件可有效抑制咬边的产生,最后,通过对不同预热温度下的工件进行TIG焊接实验,验证了数值模拟结果的正确性。     

基于Fluent的合金化炉保温段温度场的数值模拟

建立合金化炉保温段内空气流动与热交换的物理与数学模型,利用Fluent软件,采用标准κ-ε湍流模型,对合金化炉保温段内气体流场和温度场的分布进行数值模拟研究.经分析知模拟结果与实际情况较吻合,此方法对了解和控制合金化炉内的温度分布具有指导意义.     

Numerical Simulation of the Thermal Process in a W-Shape Radiant Tube Burner

In the current work, three-dimensional mathematical models were developed for the heat transfer and combustion in a W-shape radiant tube burner (RTB) and were solved using Fluent software (ANSYS Inc., Canonsburg, PA). The standard k–ε model, nonpremixed combustion model, and the discrete ordinate model were used for the modeling of turbulence, combustion, and radiant heat transfer, respectively. In addition, the NO _x postprocessor was used for the prediction of the NO emission. A corresponding experiment was performed for the validation of mathematical models. The details of fluid flow, heat transfer, and combustion in the RTB were investigated. Moreover, the effect of the air/fuel ratio (A/F) and air staging on the performance of RTB was studied with the reference indexes including heat efficiency, maximum temperature difference on shell wall, and NO emission at the outlet. The results indicated that a low speed zone formed in the vicinity of the combustion chamber outlet, and there were two relative high-temperature zones in the RTB, one in combustion chamber that favored the flame stability and the other from the main flame in the RTB. The maximum temperature difference was 95.48 K. As the A/F increased, the temperature increased first and then decreased. As the ratio of the primary to secondary air increased, the recirculation zone at the outlet of combustion chamber shrank gradually to disappear, and the flame length was longer and the temperature in flame decreased correspondingly.     

Mathematical Modeling and Experimental Validation of the Warm Spray (Two-Stage HVOF) Process

The warm spray (WS) gun was developed to make an oxidation-free coating of temperature-sensitive material, such as titanium and copper, on a substrate. The gun has a combustion chamber followed by a mixing chamber, in which the combustion gas is mixed with the nitrogen gas at room temperature. The temperature of the mixed gas can be controlled in the range of about 1000-2500 K by adjusting the mass flow rate of nitrogen gas. The gas in the mixing chamber is accelerated to supersonic speed through a converging-diverging nozzle followed by a straight barrel. This paper shows how to construct the mathematical model of the gas flow and particle velocity/temperature of the WS process. The model consists of four parts: (a) thermodynamic and gas-dynamic calculations of combustion and mixing chambers, (b) quasi-one-dimensional calculation of the internal gas flow of the gun, (c) semiempirical calculation of the jet flow from the gun exit, and (d) calculation of particle velocity and temperature traveling in the gas flow. The validity of the mathematical model is confirmed by the experimental results of the aluminum particle sprayed by the WS gun.     

Optimization of the Number of Burner Nozzles in a Hot Blast Stove by the Way of Simulation

The structure of the burner nozzles in a blast furnace hot stove including their number, location, and angle has a vital effect on the flow field, temperature distribution, combustion efficiency, etc. In this article, simulation models were established for the hot stove located at Shougang Qianan. The \( k{-}\varepsilon \) model, eddy dissipation model, and P-1 model were used for the modeling of turbulence, combustion, and radiative heat transfer, respectively. The effect of different number of burner nozzles on the flow field and temperature distribution in the combustion chamber was investigated. The results indicated that 19 or 21 burner nozzles were preferred to obtain the optimum flow field and temperature distribution.     

高炉风口回旋区三维数学模型

建立了高炉风口回旋区气体运动，温度分布和物质传输的三维数学模型，用它预报生产高炉回旋区内速度场，温度场和浓度场。     

过量空气系数及喂煤量对回转窑温度分布影响

在对回转窑已有传热研究基础上,进一步考虑了水泥回转窑煤粉燃烧和窑内化学反应,建立了计算回转窑温度分布的综合数学模型;基于此模型利用Matlab软件编程研究过量空气系数和喂煤量对回转窑温度分布的影响,得出了过量空气系数和喂煤量对窑内烟气、物料和筒体外表面温度分布的影响规律。并将计算所得的窑筒体外表面温度分布与实测值相比较,两者具有较好的一致性,验证了所建立的回转窑温度场计算模型的有效性。     

压铸机压室温度分布与变形的二维模拟

针对卧式冷室压铸机压室的工作环境 ,提出三种不同的热传递数学模型。使用ABAQUS软件模拟压室在工作过程中的二维温度分布的几何变形状况。对比模拟和试验结果 ,得到了优化的数学模型