高温空气烧嘴参数对NOx排放影响的试验研究

设计合理的烧嘴可以控制空气和燃气的混合,从而控制Nox的排放.对6种不同几何结构烧嘴在不同的燃气流速、过量空气系数、燃气流量以及不同燃气与空气喷口间距下的Nox排放量进行了试验研究.结果表明,燃气射流速度的提高可以减少Nox的排放;在空气射流速度大致相等的各个试验工况中,空气喷口为矩形且矩形短轴指向烧嘴中心的燃气喷口时,Nox排放量最高,空气喷口为圆形时次之,空气喷口为矩形且矩形长轴指向燃气喷口时Nox排放量较低.在试验范围内,过量空气系数提高,Nox的排放增加.     

增压锅炉耐火砖衬结构的断裂失效分析

针对增压锅炉炉膛耐火砖衬出现横向裂纹的现象,综合考虑耐火砖所承受的热冲击、高温烟气冲刷及机械载荷的复杂工作环境,对局部砖衬结构进行了三维仿真建模,采用有限元方法进行瞬态温度场和应力场计算。结果分析表明：耐火砖衬结构的断裂失效主要是由于增压锅炉快速升、降温过程引起的拉压应力反复作用所致的疲劳损伤,停炉降温过程中的拉应力是引起断裂失效的直接原因。     

地下热流固耦合对EGS热开采的影响

人工热储的孔隙率及渗透率在增强型地热系统（EGS）地下热开采过程中受温度（T）、水力（H）、应力（M）的综合影响。本文建立了EGS热开采过程THM耦合的三维计算模型,并采用局部非热平衡假设处理液岩对流换热。对一理想的五口井EGS系统采热过程进行了THM模拟计算,分析了岩石温度、孔隙压力对岩石应力场的作用机理,进一步研究了应力场对EGS采热性能的影响。结果表明,开采过程中岩石应力场为热储内孔隙压力和温差综合作用的结果,由孔隙压力造成的岩石应力为压应力,仅集中于注入井附近,由岩石温度变化引起的热应力为拉应力,随着热开采区域的扩展而扩展。液−岩温差是触发工质与岩石热交换的动因,同时也是产生热应力的根本。     

旋转气流对低压油烧嘴特性的影响

通过实验研究了旋转气流对低压油烧嘴的油流量、空气流量、空气和油射流扩张角、射流横截面上的油流量分布、油滴平均直径等冷态特性以及对点火性能、火焰温度、火焰长度等热态特性的影响。结果表明:采用旋转气流及用改变旋流强度的方法来调节低压油烧嘴的火焰长度是切实可行的。     

涡轮盘-片耦合场及接触问题的热弹塑性分析

针时某燃气轮机动力涡轮叶片和轮盘,结合PRO/E与ANSYS建立了耦合场及接触有限元模型,并进行了瞬态热弹塑性分析,得到了轮盘及叶片启动过程中的应力应变时间历程.本文在应力应变分析中融合了热流固耦合及接触分析方法,因此得到的结论比较全面精确地反映出装置实际情况,并为燃气轮机的寿命预测提供了可靠的数据.     

KMY新型气泡雾化烧嘴在本钢1700mm热带钢加热炉上的应用

本文主要阐述了本钢一米七热带钢连轧机投产18年来，其加热炉烧嘴经常出现结焦、堵塞、漏油、漏气，炉内冒黑烟，热值降低，以及造成钢坯氧化铁皮严重等问题，经过技术分析找出造成问题的主要原因是烧嘴的质量问题。对其烧嘴进行改造更新后出现可喜效果。     

表征异型碳化硅耐火砖热震稳定性的临界毕渥数

为表征某异型碳化硅耐火砖的抗热震性能,通过有限元仿真软件Abaqus建立其三维模型,仿真计算得出其热冲击条件下不同传热毕渥数下的瞬态温度场和热应力场。合理选取热应力和温度随时间变化的观测点,通过对其数据的提取,定义并计算分析无量纲热应力、无量纲温度与无量纲时间主要的变化关系。结果显示,毕渥数显著影响热震持续时间进而影响试件对热震的敏感性,同时得到一个临界毕渥数为表征此型耐火砖的抗热震性能的一个参数,为耐火砖的设计和应用提供了参考依据。     

烧嘴流速对辊道窑烧成带内温度分布影响的数值研究

建立了辊道窑烧成带的三维物理模型,借助计算流体力学(CFD)软件FLUENT6.0模拟烧成带的工况,研究烧嘴流速对烧成带内温度分布的影响,为辊道窑的运行提供了有益的参考,也为烧嘴研制的基础性工作提供理论支持。     

多种载荷下超临界二氧化碳向心透平变形及应力研究

基于超临界二氧化碳(SCO2)工质的动力循环系统是目前先进动力系统的研究热点和发展方向，向心 透平作为SCO2动力循环中的核心部件，其运行的安全性至关重要。本文采用热流固耦合分析方法，对一SCO2 向心透平叶轮进行了强度特性分析，得到了多种载荷对于叶轮变形和应力分布的影响。结果表明:温度 载荷对于变形大小占据主导地位，气动载荷及离心力载荷对变形影响较小，全部载荷工况下叶轮最大总位移 为2.421 mm，位于叶轮轮盘外径处;离心力载荷对等效应力贡献最大，温度载荷导致叶轮叶片根部前缘圆角 处的应力集中，气动载荷对叶轮等效应力贡献较小，全部载荷工况下叶轮最大等效应力为267.91 MPa，位于 叶轮轮背凸台段过渡圆弧处 。     

射流参数对高温空气燃烧影响的数值分析

利用fluent流体软件对一种蓄热式烧嘴燃烧性能的影响因素进行了数值分析。研究发现,适当控制预燃室内一次空气的喷入量,可增大火焰体积和温度的分布数值,增强炉温分布的均匀性和降低NOx排放;对比一次空气和煤气单预热时温度场的变化发现,煤气单预热时,火焰长度长,温度高;当两者双预热时炉膛整体温度显著增大;比较煤气和一次空气不同预热方式下炉温的均匀性,双预热时最好,不预热时次之,单预热时最差。     

炉渣对转炉镁碳砖侵蚀行为的实验研究

随着对钢铁性能要求的提高,耐火材料对转炉整体使用寿命以及生产成本的影响越来越大,因而对镁碳砖的抗渣性能提出了更高的要求。以转炉冶炼过程为研究对象,通过开展静态条件下镁碳砖侵蚀高温模拟实验,研究了炉渣成分对镁碳砖损毁行为的影响,并利用多种分析手段对侵蚀后的镁碳砖试样进行了处理分析。结果表明,适当提高炉渣中MgO的质量分数、炉渣碱度以及降低转炉冶炼后期炉渣中FeO的质量分数可有效降低炉渣对镁碳砖的侵蚀。     

Fractal structure reconstruction for alumina-silicate refractory fiber and simulation of the thermal conductivity

In this paper, it is proved that the intemal porous structure of alumina-silicate refractory fiber has fractal characteristics, which is reconstructed by the computer and the reconstructed structure further proved to have fractal characteristics. Based on the reconstructed structure, the network-thermal-resistance model is established to calculate the thermal conductivity of the fiber. It is shown that the calculated results agree well with the previous experimental ones, proving the correctness of the method.     

Influence of thermal and solutal Marangoni effects on free surface deformation in an open rectangular cavity

Steady thermo-solutocapillary convection in a rectangular cavity with deformable free surface under microgravity condition is numerically studied, where level set method is employed to capture the free surface deformation. Both the temperature and solute concentration gradients are applied horizontally. The computational results show that, as the thermal to solutal Marangoni number ratio varies between-10 and-1(namely,-10 ≤ R_σ -1), the flow field exists one anti-clockwise rotating convective cell driven by thermocapillary convection, and the free surface bulges out near the left end wall and bulges in near the right end wall. As-1 R_σ 0, the flow field exists one clockwise rotating convective cell driven by solutocapillary convection, and the free surface bulges out near the right end wall and bulges in near the left end wall. As R_σ =-1, the flow field consists of one clockwise and one anti-clockwise rotating convective cells, and the free surface bulges in at the central point and bulges out near the left and right end walls.     

Catalytic thermal decomposition and combustion of composite BAMO-THF propellants

In formulations of the composite BAMO-THF/AP/RDX/Al propellants, the influence of the catalysts OME, Fe₂O₃, and their composition on the propellants was discussed. The burning rates of the composite propellants were measured at pressures of 2 to 10 MPa. A thermal analysis of the BAMO-THF binders and the composite propellants containing the catalysts mentioned was carried out. Scanning electron microscopy and reflection FTIR spectroscopy were used to characterize the quenched burning surfaces of the propellants. The results showed that all of the catalysts could accelerate the thermal decomposition of the composite BAMO-THF propellants and increase their burning rates. However, OME accelerates the thermal decomposition of both the binder and AP, while Fe₂O₃ only affects the decomposition of AP.     

稠油地面蒸汽管线热力参数影响及保温厚度优化

提高蒸汽注汽品质和优化保温层厚度是改善地面蒸汽管线热力输运、实现稠油高效开采的关键。建立了油田地面蒸汽管线热力参数计算模型和保温层厚度经济性分析模型,基于分段微元方法求解沿程蒸汽干度、热损等特性参数,分析了锅炉出口蒸汽参数和注汽流量的影响规律,并结合经济厚度法的计算原理优化了保温层厚度。结果表明：提高锅炉出口蒸汽温度和压力,沿程蒸汽干度降低速度变快,沿程热损增加变快,与锅炉出口蒸汽温度313 oC,压力10.2 MPa相比,其热损最大增加11.15%;增加注汽流量,蒸汽干度提升且随管线沿程降幅缩小,等梯度注汽流量差下,高注汽流量时蒸汽干度降幅较小,其降幅为3.58%;经济厚度为0.33m时,其热损费用同比原有厚度可降低68.22%。     

Application of soft computing techniques to optimize thermal parameters in a double heat exchanger with cylindrical turbulators

In the present study, the dimensions of the cylindrical turbulators have been optimized to achieve the highest thermal performance. A double pipe heat exchanger with cylindrical turbulators placed in the annulus side is modeled and a numerical simulation is carried out for different operating conditions. The simulation is conducted for different diameters of the turbulators for various Re for the annulus fluid. The Nusselt number (Nu), friction factor (f), and thermohydraulic performance index (THPI) are the responses simulated for the above different cases of input conditions. Response surface methodology has been used to study the influence of operating parameters on the responses. It is observed that Nu, f, and THPI increased as the Re and turbulator diameter increased. Response optimizer is used to optimize the turbulator diameter to obtain the highest thermal performance in terms of highest Nu and THPI and lowest f. The results indicated that maximum performance was obtained for a diameter of 4.45 mm and for a Re of 5530. The Nu and THPI corresponding to the above combinations are 68.4 and 2, respectively.     

不同Lennard-Jones模型参数对分子动力学模拟的影响

针对分子动力学模拟中应用广泛的Lennard-Jones模型中的参数对压力、比热容等宏观参数和表面张力的影响进行了比较和分析,发现采用不同原始数据拟合得到的参数在模拟远离临界态的压力和比热容时,各系统差别不大。与实验值的相对误差在5％;但在临界态附近,只有黏度系数和维里系数一起拟合的参数精度较高,对系统的适应性也较好并且模拟的表面张力值精度比其他参数高很多,相对误差在3．5％。最后根据参数对径向分布函数的影响,给出反应机理的解释。     

结构参数对平焰燃烧器流场的影响

针对现有的天然气平焰燃烧器,采用RNGk-ε湍流模型和EDM燃烧模型,运用计算流体力学软件和建模工具对天然气平焰燃烧器流场进行了数值模拟,并应用五孔探针等工具对天然气平焰燃烧器冷态流场进行了测试,模拟结果分析表明:燃料径向喷出、空气进口偏心距l/D为0.476、烧嘴砖曲率半径R/D为1.14~1.71、旋流数S为0.61~1.68、混合距离L/D为0.6~0.9时能获得较佳的燃烧效果(其中,D为燃烧器喷口直径)。通过分析比较模拟结果和试验结果,发现两者的分布规律基本一致,数据基本吻合,回流区和主流区基本相同,并且与理论分析一致,符合实际情况,说明了天然气平焰燃烧器流场数值模拟结果是真实可信的,可为天然气平焰燃烧器的工业应用提供重要参考依据,也为天然气平焰燃烧器的设计、研究提供了有效的研究方法和途径。     

Influence of natural convection on the parameters of thermal explosion in the horizontal cylinder

The problem of a thermal explosion in the cylinder has been solved taking into account the natural convection. Both the classical solution of the Frank-Kamenetskii model and a realistic model of a thermal emission which takes into consideration reverse endothermic processes have been considered. It is shown that in this case the solution exists for any value of the energy influx into system. However, under certain conditions a sharp transition into the area of high temperatures still occurs which corresponds to the thermal explosion. It is shown that convection leads to significant change of the parameters of the thermal explosion. The results of this consideration are of interest for the theory of lasers and discharges where the Rayleigh numbers are rather large and the influence of convection appears to be essential.     

感应熔锌炉熔沟耐火材料

介绍了工频有心感应熔锌炉熔沟耐火材料的主材料、结合剂及添加物的选择,并提供了XL401熔沟耐火材料的组分及其性能参数,该牌号的使用寿命可达3年。