Conductive heat transfer in a gas confined between two concentric spheres: From free-molecular to continuum flow regime
Conductive heat transfer in a gas confined between two concentric spheres: From free-molecular to continuum flow regime
复制标题
DOI：
10.1016/j.ijheatmasstransfer.2016.12.100
复制
发表时间：
2017-05
影响因子：
5.2
通讯作者：
H. Yamaguchi;M. Ho;Y. Matsuda;T. Niimi;I. Graur
中科院分区：
文献类型：
--
作者：
H. Yamaguchi;M. Ho;Y. Matsuda;T. Niimi;I. Graur
从自由分子流态到连续流态，研究了通过限制在不同温度的两个同心球壳之间的气体进行的传导传热。使用最近提出的实验系统来提取热调节系数来测量热通量，并将其与解析表达式和数值结果进行比较。通过比较发现，在自由分子流极限下，球面任意半径和温度比的解析表达式可以很好地解释实验数据。在连续极限下，解析表达式中应考虑导热系数的温度依赖性。在过渡流态中，提出了热通量插值的修正函数，以更好地拟合数值结果。通过利用这些知识，修改了系统的热调节系数提取程序，并且表明重新计算的调节系数可以很好地再现测量的热通量。
The conductive heat transfer through a gas confined between two concentric spherical shells maintained at different temperatures is investigated from the free-molecular to the continuum flow regime. The heat flux, measured using a recently proposed experimental system to extract the thermal accommodation coefficient, is compared with analytical expressions and numerical results. From this comparison it is found that in the free-molecular flow limit, the experimental data are well explained by the analytical expression for the arbitrary radius and temperature ratios of the spherical surfaces. In the continuum limit, the temperature dependence of the thermal conductivity coefficient should be considered in the analytical expression. In the transitional flow regime, a revised function for the heat flux interpolation is proposed to give better fitting to the numerical results. By employing these knowledge, the thermal accommodation coefficient extraction procedure for the system is revised, and it is shown that the re-calculated accommodation coefficient allows to reproduce well the measured heat flux.