Thermal Conductivities of Complex Liquids Relevant to Process Modelling

该项目的目的是测量与工艺建模有关的金属、半导体和氧化物熔体的导热系数，并讨论这些方法中的导热机理。一种测量金属和半导体熔体导热系数的新方法发展了一种测量金属熔体导热系数的非稳态热线法。在室温下测得汞的测量值为8.2W/mK，在573K时测得熔融的铅的测量值为15W/mK，与相应的公布值符合得很好。锡及锡铟合金熔体的导热系数在600K时，锡的导热系数为28W/mK，并随着温度的升高而略有增加。In的加入降低了材料的热导率及其与温度的依赖关系。维德曼-弗兰兹定律对高温金属的适用性维德曼-弗兰兹定律是用自由电…的比热推导出来的提出了一个由电导率和电子比热估算金属高温导热系数的新公式，后者是用实际金属的电子态密度来计算的。1700K时，硅熔体的导热系数为57W/mK，且随温度的升高而略有增加。在低于熔点的1673K下，固体硅的测量值为19W/mK。研究发现，在熔化过程中，硅的导热系数急剧增加。用非稳态热线法测量了Li_2O-SiO_2、Na_2O-SiO_2和K_2O-SiO_2三种玻璃熔体的热导率。导热系数随碱金属半径的增大而减小。研究表明，碱性氧离子与非桥氧离子之间的化学键越离子，导热系数越小。分别对含LiF和NaF的Li_2O-SiO_2和Na_2O-SiO_2玻璃熔体进行了热导率测定。在这两种体系中，导热系数都随着氟化物的加入而降低。这种下降可能是由于氟破坏了硅酸盐的网络结构。较少

The aim of this project was to measure thermal conductivities of metal, semiconductor and oxide melts relevant to process modelling and to discuss thermal conduction mechanisms in the metls.1. Development of a new method for measuring thermal conductivity of metal and semiconductor meltsThe nonstationary hot wire method with an insulator-coated probe has been developed to measure thermal conductivities for molten metals. Values measures on Hg and molten Pb are 8.2 W/mK at room temperature and 15 W/mK at 573 K, respectively, and are in good agreement with corresponding published values.2. Thermal conductivity of molten Sn and Sn-In alloysThe thermal conductivity measured on Sn is 28 W/mK at 600K and increases slightly with an increase in temperature. Additions of In result in a decrease in the thermal conductivity and its temperature dependence.3. Applicability of the Wiedemann-Franz law to metals at high temperatureThe Wiedemann-Franz law was derived using specific heat of free electro … More n. A new equation has been proposed to estimate thermal conductivity of metals at high temperature from electrical conductivity and electronic specific heat, the latter being calculated using the electron density of states for actual metals.4. Thermal conductivity of molten SiThe measured value is 57 W/mK at 1700 K and increases slightly with an increase in temperature. The value measured on solid Si is 19 W/mK at 1673 K just below the melting point. It has been found that the thermal conductivity of Si increases drastically on melting.5. Thermal conductivity of alkali silicate glass meltsThermal conductivities of Li_2O-SiO_2, Na_2O-SiO_2 and K_2O-SiO_2 melts were measured using the nonstationary hot wire method. The thermal conductivity decreases as the radius of alkali metals becomes larger. It has been condcluded that the thermal conductivity becomes smaller as the chemical bond between alkali and nonbridging oxygen ions is more ionic.6. Effect of fluoride additions to thermal conductivity of alkali silicate glass meltsMeasurements were carried out on Li_2O-SiO_2 and Na_2O-SiO_2 melts contained LiF and NaF, respectively. In both systems the thermal conductivities decrease with additions of the fluorides. This decrease would be due to breaking of the network structure of silicates by fluorine. Less