Recent Development in the Investigation on Thermal Conductivity of Silicate Melts
Recent Development in the Investigation on Thermal Conductivity of Silicate Melts
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DOI：
10.1515/htmp-2012-0085
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发表时间：
2012-10
期刊：
影响因子：
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通讯作者：
H. Hasegawa;H. Ohta;H. Shibata;Y. Waseda
中科院分区：
文献类型：
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作者：
H. Hasegawa;H. Ohta;H. Shibata;Y. Waseda
系统地测量硅酸盐熔体的热导率随化学成分的变化，对于了解硅酸盐熔体的传热机理是必要的。热线法和激光闪光法已被用来测量高温下氧化物熔体的热导率或热扩散率。对激光闪光法进行了改进，使其能高精度地测量氧化物熔体的热扩散率。然而，辐射热传递和样品的低电阻率的影响已经使得很难得到精确的值。为了克服这些困难，提出了一种采用高时间分辨率探测器的前端加热前端探测激光闪光的方法。测量了脉冲激光辐照下含样品的薄铂电池底面的温度响应。对氧化物熔体的测量技术进行了比较。在此基础上，测量了Al_2O_3-Na_2 O-CaO-SiO_2硅酸盐熔体在1830 K以下的热导率。熔融硅酸盐的热导率显示微不足道的温度依赖性，所有调查的熔体。热导率与由化学组成计算的NBO/T（非桥氧离子/四面体配位阳离子）值之间有较好的相关性。当NBO/T值较小时，导热系数随NBO/T值的减小而增大，当NBO/T值较大时，导热系数趋于恒定。
Abstract Accurate values of thermal conductivity of the silicate melts systematically measured as a function of chemical composition are necessary to understand a mechanism of heat transfer in the silicate melts. Hot wire method and laser flash methods have been used to measure thermal conductivity or thermal diffusivity of oxides melts at high temperatures. Laser flash method has been improved to measure thermal diffusivity of oxides melts with high accuracy. However the effects of radiative heat transfer and low electrical resistivity of samples have been made it difficult to derive precise values. To overcome these difficulties, a front-heating front-detection laser flash method with use of high time resolution detector has been proposed. The temperature response at the bottom surface of thin platinum cell containing sample irradiated by pulse laser is measured. The measurement techniques used for measurement oxide melts are compared. Then, thermal conductivity of Al2O3-Na2O-CaO-SiO2 silicate melts was measured at temperature up to 1830 K. Thermal conductivity of the molten silicate shows insignificant temperature dependence for all investigated melts. A fairly good correlation has been found between the thermal conductivity and the value of NBO/T (Non-Bridging Oxygen ions/Tetrahedrally coordinated cation) calculated from the chemical composition. The thermal conductivity increases with decrease of NBO/T for small NBO/T value and becomes constant for larger NBO/T value.