ADU微球连续焙烧设备热场流场数值模拟

根据现有生产经验，ADU微球连续焙烧设备的最大难点是如何做到炉内气体均匀和温度场均匀，通过热场、流场数值模拟，在设备设计阶段充分论证设备结构，确保研制出的ADU微球连续焙烧设备不存在热场、流场不均匀、设备结构不合理等较大缺陷。基于ADU微球连续焙烧设备的自身特点，对焙烧设备的热场流场进行了模拟分析，综合考虑焙烧设备中的导热、对流、辐射等传热方式，获得在模拟稳定运行状态下炉内温度场、流场的分布情况，为ADU微球连续焙烧设备结构设计及制造提供一定的理论数据支持。     

气体横掠单管强制对流换热的大涡模拟

应用大涡模拟与二价全展开ETC有限元离散格式相结合的方法对气体横掠单管强制对流换热进行了数值模拟,分别计算了气体横掠团管和方管时的温度场,得到了管壁平均换热系数,数值结果与实验关联式符合较好。同时还表明大涡模拟方法善于捕捉温度场以及流场涡系的时间演化过程,非常适合于具有大尺度涡的绕流运动温度场的分析。     

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。     

基于PDF模型的阳极焙烧炉仿真分析研究

为了探索阳极焙烧炉在焙烧质量方面存在的问题,研究分析了阳极焙烧炉现场实际情况,进行了模型简化处理和假设。借助商业软件Fluent,根据边界条件和模型近似假设,建立了阳极焙烧炉的物理模型。基于PDF(Probability Density Function)模型,结合计算传热学和计算流体力学的原理和数学模型,对焙烧炉进行了数值仿真分析研究。重点研究了火道内的流场、温度场和浓度场及其在火道内的分布规律,流场、温度场和浓度场之间的关系及其对阳极焙烧质量的影响。分析得到现有焙烧炉炉型存在的不足,     

多晶硅氢化炉多场耦合的数值模拟

利用计算流体力学软件,考虑包括质量传递、动量传递、热量传递模型,对18对棒西门子多晶硅氢化炉进行数值模拟,得到了多晶硅氢化炉内的流场、温度场,分别从轴向和径向对流动情况以及温度分布进行了分析。通过与实际生产情况进行比较,表明流场、温度场数值模拟的可靠性和准确性。     

盘管式有机热载体炉炉内流动换热分析

利用ANSYS CFX数值模拟了盘管式有机热载体炉内层盘管前10个流程的流场及温度场的分布,分析结果表明有机热载体流场分布在管段横截面上沿半径方向的变化明显,其温升主要集中在前段流程内,有机热载体过热的风险随流程的增加而提高,提高有机热载体流速可以有效改善管段内侧近壁面的流场和温度场。通过对实际炉型数值模拟得出的流动阻力系数和流动换热系数与理论计算值进行对比分析,验证了此模型的可靠性。     

钢管再加热炉炉内温度场和流场分布数值模拟

以某公司钢管再加热炉为研究对象,运用Fluent数值仿真软件对钢管再加热炉内温度场和流场进行了数值模拟,获得该加热炉的温度场和流场的分布图。计算结果为优化炉型结构提供了参考依据。     

等离子体发生器内高温空气化学反应流场分析

空气在高温环境下会发生离解、电离等化学反应使组分发生变化，从而引起流场状态的改变。以一个低温等离子发生器模型为例，应用数值模拟的方法对七种组分，七个化学反应的流场求解，并与纯空气流场的求解结果进行比较．分析化学反应流场流动和传热的特点。在数值模拟过程中采用了局部热力学平衡流体模型，数值格式用SIMPLEC算法，采用贴体坐标的网格模型。计算结果给出了温度场、速度场及组分变化分布图。     

电弧等离子体点火器湍流燃烧流场传热与流动数值模拟

对燃气轮机燃烧室电弧等离子体点火器内湍流燃烧流场,进行了传热与流动数值模拟。采用了RNGk-ε湍流模型、扩散燃烧模型和离散传播辐射DTRM模型。计算域包括点火器内的等离子体发生器和点火器主体。将计算结果与未考虑辐射的温度场和流场进行了比较。结果表明辐射模型对其温度场有影响,对速度场影响不大;在点火器出口处的径向温度分布是均匀的。     

卫生洁具辊道窑的三维数值模拟研究

利用FLUENT软件对48 m新型节能环保卫生洁具辊道窑进行温度场、流场三维数值模拟,研究了其在烧成带内的燃烧工况,研究了卫生洁具在烧成带内的平均温度与表面温度均匀性及流场分布,提出了一种能够分析炉窑内焙烧产品的表面温度分布均匀性的方法,并通过卫生洁具表面温度云图得出了其表面上下、左右温差,为实际辊道窑运行和优化提供有价值的理论指导.     

热分析法在吸收式制冷机中的应用

由于影响吸收式制冷机的因素很多，针对吸收式制冷机性能评价的复杂性，运用COP分析法、Yong分析法、热经济学分析法对吸收式制冷机性能进行评价，得到三种方法各自的特点，COP分析法是从热力学第一定律对系统进行衡算，Yong分析法是热力学第一定律与热力学第二定律相结合的产物，热经济分析法是经济优化技术与Yong分析法的结合．分析了它们在吸收式制冷机性能优化过程中所起的作用。     

建筑能耗分析方法的研究与实例

建筑能耗分析是建筑节能和建筑能效管理的基础。在分析常用建筑能耗分析方法的基础上,对比了计算机模拟法、度日法、温频法三种方法的优缺点,并简要介绍一些改进措施,使计算结果更符合实际情况,为建筑能耗计算及节能措施研究提供有益的参考。     

Improvement of the pulsed photothermal technique for the measurement of the convective heat transfer coefficient

<正>The present study concerns the measurement of the convective heat transfer coefficient on the solid-fluid interface by the pulsed photothermal method.This non-intrusive technique is apphed for the measurement of the local heat transfer coefficients in cooling of a rectangular slab that simulates an electronic component.The heat transfer coefficient is deduced from the evolution of the transient temperature induced by a sudden deposit of a luminous energy on the front face of the slab.In order to draw up the heat transfer cartography by a non-destructive tool, the infrared thermography has been used.Two inverse techniques for the identification of the heat transfer coefficient are presented here.The first one is based on the assumption that heat transfer coefficient remains constant during the pulsed experiment,and the second one considered it variable in space and time.The temporal and spatial evolutions are expressed as a constant heat transfer coefficient(h_0)multiplied by a function of time and space f(x,t).The function f is deduced from the resolution of the conjugated convection-conduction problem,by a control volume technique for the case of thermally thick sample.The results are given for different air velocities and deflection angles of the flow.     

岩石力学数值方法的作用与地位浅析

论述了岩石力学传统的研究方法的局限性，指出了岩石力学数值研究方法的优势与作用，同时探讨了岩石力学数值方法、数值分析软件当前存在的问题及不足，分析了21世纪岩石力学数值方法所能承担的及应该承担的任务。     

Transformation of independent variables of problem for increasing the POD method efficiency

Problems of the increase of the proper orthogonal decomposition method (POD) approximation efficiency by transformation of independent variables of investigated problem are considered. Transformation carried out taking into account the physical process character, problem symmetries and investigated fields topological peculiarities permits to reflect dominant spatio-temporal structures of the investigated problem using approximative representation with small number of basis functions. Examples demonstrating the efficiency of the described approach are presented.     

PLC仍在全方位地发展(上)

以中心点法和验算点法为代表的一次二阶矩方法计算简便,但对非线性程度较高的结构功能函数,其计算结果与精确度相差过大。应用数学逼近中的拉普拉斯渐进方法将非线性功能函数在验算点处作二次展开来研究结构的可靠度问题,能较高精度的逼近精确结果。算例分析表明,当随机变量的数目较多时,由一次二阶矩方法计算的结果与精确解相差较大,而二次二阶矩方法的计算结果与精确解非常接近。     

Solution of periodic heating problems by the transfer matrix method

For discretized linear periodic heating problems, the nodal temperatures at the end of a heating cycle must be a linear function of those at the beginning of the same cycle and of any reservoirs with which the system exchanges heat. If the matrix of coefficients defining this system of linear equations is determined, it can be applied sequentially to advance through the transient response to the system without the need for direct numerical simulation of every cycle. It also permits a direct solution for the nodal temperatures at an appropriate time during the steady periodic state. Methods of determining the required matrices are discussed and the method is applied to a simple example.     

Modelling energy demand of developing countries: Are the specific features adequately captured?

This paper critically reviews existing energy demand forecasting methodologies highlighting the methodological diversities and developments over the past four decades in order to investigate whether the existing energy demand models are appropriate for capturing the specific features of developing countries. The study finds that two types of approaches, econometric and end-use accounting, are commonly used in the existing energy demand models. Although energy demand models have greatly evolved since the early seventies, key issues such as the poor–rich and urban–rural divides, traditional energy resources and differentiation between commercial and non-commercial energy commodities are often poorly reflected in these models. While the end-use energy accounting models with detailed sectoral representations produce more realistic projections as compared to the econometric models, they still suffer from huge data deficiencies especially in developing countries. Development and maintenance of more detailed energy databases, further development of models to better reflect developing country context and institutionalizing the modelling capacity in developing countries are the key requirements for energy demand modelling to deliver richer and more reliable input to policy formulation in developing countries.     

关于常规热平衡法、等效焓降法整体算法和等效焓降法局部简化算法的一致性的探讨

分析证明了常规热平衡法、等效焓降法整体算法和等效焓降法局部简化算法的一致性。并特别讨论了当热力系统的局部变化是由于加热器在混合式和疏水逐级自流式之间切换而引起时 ,用等效焓降法局部算法进行计算应注意的问题。