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Determination of effective thermal conductivity for polyurethane foam by use of fractal method

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Science China(Technological Sciences) 2006年第4期49卷 468-475页

作者： shi mingheng LI Xiaochuan CHEN Yongping Department of Power Engineering Southeast University Nanjing 210096 China Department of Power Engineering Southeast University Nanjing 210096 China Department of Power Engineering Southeast University Nanjing 210096 China

The microstructure of polyurethane foam is disordered, which influences the foam heat conduction process significantly. In this paper foam structure is described by using the local area fractal dimension in a certain small range of length scales. An equivalent element cell is constructed based on the local fractal dimensions along the directions parallel; transverse to the heat flux. By use of fractal void fraction a simplified heat conduction model is proposed to calculate the effective thermal conductivity of polyurethane foam. The predicted effective thermal conductivity agrees well with the experimental data.

关键词： polyurethane foam, porous media, thermal conductivity, fractal.

Removal of dust from flue gas in magnetically stabilized fluidized bed

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Particuology 2008年第2期6卷 116-119页

作者： Yinghui Wang Keting Gui mingheng shi Changfeng Li School of Energy and Power Engineering Jiangsu University Zhenjiang 212013 Jiangsu China Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education Southeast University Nanjing 210096 Jiangsu China

A magnetically stabilized fluidized bed （MSFB,Ф 500mm×2100mm） was designed to study dust removal from flue gas. Based on the mechanism of dust removal in a fixed bed, the effects on collection efficiency of magnetic field intensity, ratio of flue gas velocity to minimum fluidization velocity, bed height, and particle average diameter, were investigated. Then feasible methods for MSFB to better remove dust were proposed. Over 95 % of dust removal with MSFB can be achieved, when stable fluidization is maintained and when magnetic particles are frequently renewed.

关键词： Magnetically stabilized fluidized bed (MSFB) Stable fluidization Dust removal Magnetic particles renewal

Study on the melting process of phase change materials in metal foams using lattice Boltzmann method

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Science China(Technological Sciences) 2010年第11期53卷 3079-3087页

作者： GAO DongYan CHEN ZhenQian shi mingheng WU ZhiShen School of Energy and Environment Southeast UniversityNanjing 210096China International Institute for Urban Systems Engineerin Southeast UniversityNanjing 210096China

A thermal lattice Boltzmann model is developed for the melting process of phase change material (PCM) embedded in open-cell metal foams. Natural convection in the melt PCM is considered. Under the condition of local thermal non-equilibrium between the metal matrix and PCM, two evolution equations of temperature distribution function are pre-sented through selecting an equilibrium distribution function and a nonlinear source term properly. The enthalpy-based method is employed to copy with phase change problem. Melting process in a cavity of the metal foams is simulated using the present model. The melting front locations and the temperature distributions in the metal foams filled with PCM are obtained by the lattice Boltzmann method. The effects of the porosity and pore size on the melting are also investigated and discussed. The re-sults indicate that the effects of foam porosity play important roles in the overall heat transfer. For the lower porosity foams, the melting rate is comparatively greater than the higher porosity foams, due to greater heat conduction from metal foam with high heat conductivity. The foam pore size has a limited effect on the melting rate due to two counteracting effects between conduction and convection heat transfer.

关键词： lattice Boltzmann method melting natural convection phase change material metal foams

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恒热流竖壁层流降膜换热特性研究

化学工程 1999年第1期27卷 25-28页

作者：师晋生施明恒东南大学动力工程系

将能量边界层积分法应用于恒热流竖壁层流降膜热发展段，求得了无量纲热发展段长度和包括热发展段及热定型段的平均换热系数表达式。进行了降膜破裂和换热的实际，理论和实验结果的比较证明本文的理论分析是可行的。

关键词：降膜热边界层换热性化工设备恒流热

SIMULTANEOUS MEASUREMENT OF THE HEAT AND MASS DIFFUSIVITIES IN UNSATURATED MOIST SOILS USING CONSTANT HEAT FLUX METHOD

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Journal of Hydrodynamics 1998年第2期10卷 87-93页

作者： Han, Jitian Gui, Keting shi, mingheng Gong, Weiping Shandong Univ of Technology Jinan China

The simultaneous measurement of heat and mass diffusivities in unsaturated moist soils was presented by using a constant heat flux method. It can determine the heat and mass diffusivities in a moist soil through only one test. The experimental results show that the developed method is timesaving and has potential applications. It provides a new way for the fast and accurate measurement of heat and mass diffusivities in moist soils and other unsaturated wet porous media.

关键词： Diffusion in solids Heat transfer Mass transfer Moisture Sediment transport

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下降液膜层流换热发展段中的积分分析

应用力学学报 2000年第1期17卷 54-59页

作者：师晋生施明恒东南大学南京210018

对等温竖直壁面上层流液膜发展段的流动换热进行了理论分析 ,用积分法得到并求解了速度和温度边界层的积分方程式 ,求得了发展段的流动和换热特性的变化规律 ,讨论了进口流态和普朗特数对换热的影响。

关键词：液膜边界层发展段流动换热下降积分

液体除湿空调系统中除湿过程的模拟和实验研究

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太阳能学报 2011年第4期32卷 523-529页

作者：杜斌施明恒东南大学能源与环境学院南京210096

在对液体除湿机理研究的基础上,针对对流传热边界条件,建立了内冷型竖直板逆流降膜除湿过程的数学模型,并通过实验方法对该模型进行验证,实验采用CaCl2水溶液作为除湿剂,分析了各种进口参数对除湿效果的影响。结果表明:该数学模型能够... 详细信息

在对液体除湿机理研究的基础上,针对对流传热边界条件,建立了内冷型竖直板逆流降膜除湿过程的数学模型,并通过实验方法对该模型进行验证,实验采用CaCl2水溶液作为除湿剂,分析了各种进口参数对除湿效果的影响。结果表明:该数学模型能够较好地解释竖直板降膜除湿过程;空气和溶液的流量、温度,空气的含湿量,溶液的浓度等均对除湿过程有不同程度的影响。

关键词：降膜除湿数学模型内冷逆流

抛物面聚光太阳能PV/T系统的热电性能分析

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太阳能学报 2009年第11期30卷 1513-1518页

作者：孙健施明恒东南大学能源与环境学院南京210096 景德镇陶瓷学院热能工程系景德镇333001

建立了带有散热翅片的聚光太阳能PV/T热电联产系统内部传热过程的一维稳态数学模型,对传热过程进行了数值模拟,分析了空气质量流速、入射光强度、聚光比、环境温度、上部通道高度及翅片参数对系统的空气温度、电池板温度及系统热、电效... 详细信息

建立了带有散热翅片的聚光太阳能PV/T热电联产系统内部传热过程的一维稳态数学模型,对传热过程进行了数值模拟,分析了空气质量流速、入射光强度、聚光比、环境温度、上部通道高度及翅片参数对系统的空气温度、电池板温度及系统热、电效率的影响。结果表明:随着入射光强、聚光比的增加,空气出口温度和电池板温度都会增加,系统热电总效率增加;通过增加空气流量可以有效降低电池温度,提高电池的光电转换效率和系统的总能量利用效率;吸热板背面的翅片可以强化通道内空气的传热过程,降低电池板的温度,系统效率可增加约2%;在相同的光照条件下,入口空气温度越低,上部通道越窄,系统热效率越高。研究结果为聚光太阳能PV/T热电联产系统的设计和运行提供了理论依据。

关键词：聚光光电热一体化抛物面聚光器翅片热电性能聚光率

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大气对流对土壤内热湿迁移影响的实验研究

太阳能学报 1999年第1期20卷 87-92页

作者：陈振乾施明恒东南大学动力工程系

对土壤内热湿迁移过程进行了研究。通过对土壤内热湿迁移机理分析，根据质量守恒和能量守恒原理，建立了土壤非饱和区热湿迁移的理论模型。对大气对流环境条件下砂土内热湿迁移过程进行了实验研究。通过实验测量和数值计算，获得了不同... 详细信息

对土壤内热湿迁移过程进行了研究。通过对土壤内热湿迁移机理分析，根据质量守恒和能量守恒原理，建立了土壤非饱和区热湿迁移的理论模型。对大气对流环境条件下砂土内热湿迁移过程进行了实验研究。通过实验测量和数值计算，获得了不同大气对流速度作用下土壤中温度、含水率分布以及水分蒸发强度的变化。

关键词：大气对流土壤热湿迁移实验研究