A two-parameter prediction method for specific heat capacity of high-temperature inorganic crystal materials [高温无机晶体材料比热容的双参数预测方法]

作者：Wei X.; Li T.; Li B.; Sun C.

来源：洁净煤技术, 2020, 26(6): 118-125.

DOI：10.13226/j.issn.1006-6772.IF20080615

• high temperature solid
• prediction method
• specific heat capacity
• two parameter

High-temperature solid specific heat capacity is commonly used thermal property data in industrial process design, but it is difficult to obtain these data of solid with the temperature of thousands of degrees by actual measurement. Therefore, many solids with complex lattice often only have the measurement data of specific heat capacity within a limited temperature range. The Einstein and Debye models can be applied to simple mono-atomic crystals or some bi-atomic crystals for specific heat capacity prediction. However, it is difficult to accurately obtain the Debye and Einstein temperatures of polyatomic intricate lattice solids, making it difficult for Einstein and Debye models to predict these solids' specific heat capacity accurately. In this paper, based on the statistical thermodynamic method, and to determine the specific heat capacity for a solid with multiple atoms, a two-parameter prediction method for the high-temperature solid's specific heat capacity was proposed. In this method, the solid lattice vibration mode is divided into acoustic and optical branches. It is assumed that a single lattice cell has a unique Debye characteristic temperature ΘD and Einstein temperature ΘE.Moreover, the Debye characteristic temperature ΘD is obtained through the basic parameters of crystallography. The Einstein temperature ΘE of intricate lattice solid is calculated backward through the limited experimental data of the specific heat capacity of the solid or the thermal properties of simple substance. Then the solid's theoretical specific heat capacity can be predicted utilizing these two parameters at different temperatures.The two parameter prediction method is used to predict the specific heat capacity of typical monoatomic, diatomic and Polyatomic Crystals. The comparison between the calculation results and the experimental data results show that the two-parameter prediction method's error is mainly at the temperature inflection point and the high-temperature region. The prediction error of the specific heat capacity in the wide range of temperature range is less than 5%, which is expected to provide a reliable and straightforward method to determine the thermal and physical properties of solids for the process industries.

• 单位
  高温气体动力学国家重点实验室; 中国科学院大学