Transport properties of helium near the liquid-vapor critical point. I. Thermal conductivity of3He
Transport properties of helium near the liquid-vapor critical point. I. Thermal conductivity of3He
复制标题
液汽临界点附近氦的输运特性。
DOI：
10.1007/bf00655447
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发表时间：
1982
影响因子：
2
通讯作者：
H. Meyer
中科院分区：
文献类型：
--
作者：
C. Pittman;L. H. Cohen;H. Meyer
本文报道了3he的热导率λ沿临界点以上的几条等温线和沿临界等差线的研究。在详细描述了仪器和测量程序之后，给出了远离临界区域的电导率结果，并与Kerrisk和Keller的结果进行了比较。利用λ可分解为奇异部分λ singr和背景贡献的假设，用标度理论对λ singr进行了分析。λ的临界指数ψ=0.57与预测值吻合较好。与简单幂律的偏离非常接近。没有证据表明λ有对流增强。λ单尺度近似于senger提出的（ρ2kT）1/2。这里ρ和ktare是密度和可压缩性。热扩散系数dt =λ/ρCp （ecpi为比热）与散射光瑞利线宽的结果进行了比较，发现振幅存在系统差异，但仍无法解释。此外，沿着临界等差线报道了打开和关闭热通量后达到稳态的弛豫时间τ，并将其与使用稳态结果计算的热扩散率进行了比较。
A study of the thermal conductivity λ of3He is reported along several isotherms above the critical point and along the critical isochore. After a detailed description of the apparatus and the measurement procedures, the conductivity results away from the critical region are presented and compared with those of Kerrisk and Keller. Using the assumption that λ can be decomposed into a singular part λsingand a background contribution, λsingis analyzed in terms of the scaling theory. The critical exponent for λsing, ψ=0.57, is in good agreement with the predicted one. Departures from a simple power law very close toTcare discussed. There is no evidence for convective enhancement of λ. It is also found that λsingscales like (ρ2kT)1/2, as proposed by Sengers. Here ρ andkTare the density and compressibility. The thermal diffusivityDT=λ/ρCp, whereCpis the specific heat, is compared with the results obtained from the Rayleigh linewidth of scattered light, and a systematic discrepancy in amplitude is found that remains unexplained. Furthermore, the relaxation times τ for reaching the steady state after switching the heat flux on and off are reported along the critical isochore and are compared with calculations using the steady state results for the thermal diffusivity.