蓄热室传热面积的计算机计算

在总结蓄热室传热面积计算公式的基础上,开发了一套蓄热室传热面积计算的计算机软件.该软件对以往需要通过人工查表确定的气体比热设置了数据文件机器查表和曲线拟合公式计算两种处理方式;对以往需要用试差法计算的烟气出蓄热室的温度采用迭代方法进行了计算,对以往需要用查图计算方法确定的烟气黑度则利用Hottel作图原理,根据黑度定义按Schack公式进行了计算.整个软件采用中文提示西文输入的块程序结构,具有简单易学、操作方便的特点.两座池窑蓄热室传热面积的计算结果表明了所设置的气体比热的两种处理方式,烟气出蓄热室的温度迭代计算方法和烟气黑度的公式计算方法是可行的;所开发的软件有实用价值.     

蓄热室底部装设射流的研究

本文研究在蓄热室底部后墙设置射流以提高蓄热室内上升气流分布均匀性,对设置射流的影响因素、喷射器出口大小、安装位置及喷射器流量(出口速度)等因素进行了研究,确定出设置射流的最佳方案。     

蓄热室助燃空气气流的改善

本文研究了蓄热室入口形状与气流均匀性的关系，同时也研究了在具有支撑墙的蓄热室底部设置射流以提高蓄热室内上升气流的均匀性。对设置射流的影响因素如喷嘴直径、安装位置及方向等方面开展了研究，并确定了设置射流的最佳方案。     

高分子材料热导率影响因素分析

总结了影响高分子材料导热性能的因素;阐述和分析了导热性填料种类、温度、结晶度、分子链取向、密度和湿度对导热性高分子材料热导率的影响。     

高导热绝缘材料的研究进展

主要介绍了高导热绝缘材料的应用以及导热填料对高导热绝缘材料性能的影响因素。重点介绍了填料种类、尺寸、表面处理和加入量对于导热绝缘高聚物性能的影响,并分析了高导热绝缘材料的未来研究方向。     

Measurements of specific heat,thermal conductivity and thermal diffusivity of Utah tar sands

A constant applied heat flux method has been used to measure the specific heat and thermal conductivity of large samples of Utah (North-west Asphalt Ridge) tar sands as a function of temperature. Independent measurements of density allowed for the calculation of thermal diffusivity. Constituent analysis of the tar sand samples also permitted the calculation of bitumen and sand specific heats. Specific heat of the bitumen was found to increase with temperature from 1.85 to 3.9 kJ kg^?1 K^?1 for temperatures between 300 and 480 K. Specific heat of the sand matrix increased only slightly, from 0.85 to 1.0 kJ kg^?1 K^? for the same range of temperature. Corresponding thermal diffusivities for tar sand were found to decrease with temperature, and had a range of 5 · 10^?7–9 · 10^?7 m² s^?1 over the measured temperatures. It was concluded that the latent heat of both bitumen and water have a strong influence on the apparent overall specific heat of tar sand.     

热界面材料热导率和接触热阻的测试

热界面材料通常用于降低电子器件中固体界面的热阻。热界面材料的性质, 如热导率、界面材料与固体表面间的接触热阻, 对于电子器件的散热分析非常重要。然而, 这些参数通常难以获得。依据ASTM D-5470测试标准, 搭建了一个热界面测试系统。通过该系统测试了硅油和导热硅脂的热导率, 以及它们与固体基板间的接触热阻。经分析, 测试热导率和接触热阻的相对误差分别小于11.3%和41.3%。     

Highly porous nano-SiC with very low thermal conductivity and excellent high temperature behavior

Highly porous nano-SiC is fabricated by partial sintering and decarburizing process using SiC nano-powders as starting materials and graphite flakes as pore forming agents. The prepared porous nano-SiC ceramics possess multiple pore structures, including well-distributed meso-pores in the skeleton and interconnected flakelike micro-pores. The samples prepared at 1800 °C have relatively low thermal conductivities of 5.61 ～ 0.25 W m^?1 K^?1 with porosities of 55.5–76.1%. While the samples sintered at 1500 °C with porosities between 54.0% to 76.3% show very low thermal conductivities of 0.74 ～ 0.14 W m^?1 K^?1, which is attributed to the integrated nano-scale phonon-scattering mechanisms and duplex pore structures. Porous nano-SiC ceramics also show good retention of elastic stiffness up to 1350 °C and low thermal conductivity at 1400 °C. Our results shed light on porous nano-SiC as a promising thermal insulator used in extreme thermal and chemical environments.     

翅片重力热管传热性能实验研究

热管是一种利用工质相变传热,具有传热温差小、热响应速度快、换热量大等优点的传热元件。为研究翅片重力热管的传热性能,实验测试了翅片重力热管与平板重力热管（铝-丙酮工质）的传热性能,比较了其瞬态热响应速率,获得了翅片与平板重力热管在蒸发段不同电功率稳定加热条件下表面温度沿高度方向的变化规律,计算了平板热管的等效热导率,并与铝板测量结果进行了对比。结果表明：重力热管传热速度快、表面均温效果好,热导率随功率的增大先升高后降低,整体上热导率高达纯铝的84~258倍,翅片热管相比于平板热管具有更好的均温性和散热效果,在建筑供暖、车载电池散热、余热利用等领域具有广泛的应用前景。     

高导热系数活性炭的制备及其性能

基于传统的活性炭导热系数低,在脱附过程中容易产生局部过热现象,导致燃烧降低再生效率等问题,文章采用了在核桃壳原料中掺杂膨胀石墨制备高导热系数复合活性炭,分别考察了活化温度、活化时间、活化剂用量及膨胀石墨用量等不同工艺参数对活性炭结构性能的影响,对活性炭的比表面积、总孔容等进行了表征,结果表明:高导热系数活性炭的导热系数比普通活性炭提高了6倍。其直接热脱附床层温度低于实验室制备的普通活性炭25℃,同时,其甲苯脱附活化能为50.81 kJ/mol,低于在商业活性炭上的脱附活化能(68.01 kJ/mol)25%以上。保持良好的吸附性能的同时又具有很好的再生脱附效果,在活性炭脱附再生方面具有广泛的应用前景。     

振荡热管当量导热系数的理论推导与分析

把振荡热管模型简化为由管壳、液膜和振荡液塞3部分组成的具有高导热系数的复合材料。给出了振荡热管的径向和轴向当量导热系数;并从理论上推导出了振荡液塞当量导热系数的定性表达式,该导热系数与液塞的振荡频率和振荡幅度成正比;最后根据试验结果分析了热流密度、充液率和倾角等因素对当量导热系数的影响,即随着热流密度和充液率的增加,当量导热系数先增后减,倾角对当量导热系数的影响与通道弯数有关。     

聚合物基导热复合材料的研究进展

阐述了聚合物基导热复合材料的导热机制。综述了国内外导热胶粘剂、导热橡胶和导热塑料等研究进展。介绍了提高复合材料导热性能的途径,并在此基础上,展望了聚合物基导热复合材料的应用前景和未来的发展方向。     

Investigation on low-temperature sintered AlN nanoceramics with high thermal conductivity

The aim of this research was to investigate the effect of sintering additive and relatively low-sintering temperature on the thermal conductivity of aluminum nitride nanoceramic. While using nanosized AlN powder and liquid-phase sintering additives, the various sintering processes were performed at temperatures 1400 and 1500°C for several hours. In the analysis methods, thermal conductivity (K) and thermal diffusivity (α) were measured using thermal conductivity analyzer (Hot Disk), scanning electron microscope (SEM) was used to observe the surface morphology of the microstructure, x-ray diffraction analyzer (XRD) to analyze the grain size and crystal structure, Raman spectroscopy (Raman) emission spectrum was analyzed to identify the material microstructure and the densities of AlN specimens were measured by Archimedes method. It was found that the thermal conductivity is related to the densification of nanosize low-temperature sintered material, which can be controlled by additives and sintering temperature. With Y₂O₃ sintering add, the densification of AlN for low-temperature sintering increased by the factor of ～5% to ～12%, and the thermal conductivity was enhanced by 25%. The relative density observed in this research is about 78%-84%, and the thermal conductivity measured is in the range of 9-14 W/mK.     

激光导热仪在橡胶导热性能研究中的应用

简要介绍了激光导热仪的测试原理以及测试工作的注意事项等,详细介绍了如何使用激光导热仪测试炭黑／橡胶复合材料的导热性能,并对测试结果作了恰当的分析。