在确定的热力学状态下测量气体导热系数与黏度

气体的导热系数和黏度是重要的热物性参数,其数值大小取决于所处的热力学状态。在目前的导热系数和黏度主要测量方法中,待测工质在测量时需经历非定常的过程或处于具有物性梯度的非平衡态之下,使得待测工质的物性在时间或者空间上不处于一个确定的热力学状态。本文利用圆柱定程干涉法,通过分析气体导热系数和黏度导致的声波能量耗散,结合气体输运理论中对稀疏气体的描述,探索了在确定的热力学状态下同时测量气体导热系数和黏度的方法,并以氩(Ar)为例进行了实验验证。测量结果与已有文献一致性较好,初步证实了方法的可行性。

Measurements of the Viscosity and Thermal Conductivity of a Gas at Definitive Thermodynamic States

The gas viscosity and thermal conductivity are important fluid transport properties, and are related to thermodynamic states. Currently, the main methods to measure the viscosity and thermal conductivity require the gaseous samples to be exposed to non-stationary processes or non-equilibrium processes with gradients of the physical properties. Therefore, the gaseous samples are not located at a definitive thermodynamic state in time or space for each measurement. In this paper, a method to measure the gas viscosity and thermal conductivity at definitive thermodynamic states was studied by analyzing the dissipation of sound energy, which is controlled by the gas viscosity and thermal conductivity. This was performed using the transport theory for a dilute gas, based on the fixed path interference method with a cylindrical resonator. The results were verified by measuring the argon viscosity and thermal conductivity. The results agreed with data in the literature.