Time-dependent conductive heat transfer in rarefied polyatomic gases confined between parallel plates
Time-dependent conductive heat transfer in rarefied polyatomic gases confined between parallel plates
复制标题
限制在平行板之间的稀薄多原子气体中随时间变化的传导传热
DOI：
10.1088/1742-6596/785/1/012008
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
D. Valougeorgis
中科院分区：
文献类型：
--
作者：
A. Tsimpoukis;C. Tantos;D. Valougeorgis
利用动力学理论，研究了在Knudsen数的整个范围内，由于其中一块板的温度突然上升而被限制在两个无限平行板之间的稀薄气体的瞬态传热学。更具体地说，在扩散边界条件下，用Holway动力学模型来模拟随时间变化的传热流。在分子速度空间中采用离散速度法，在时间和物理空间中采用典型的有限控制体积方案，对控制积分微分方程进行了数值求解。根据表征热流的两个参数，即Knudsen数和板间施加温度比，给出了密度和温度分布以及平动和旋转热流的时间演变。重点研究了旋转自由度的影响，并对单原子气体和多原子气体进行了比较。在单原子气体和多原子气体之间，达到稳态条件所需的时间是不同的。在所有情况下，以稀疏参数表示的恢复平稳解的总时间显示出接近众所周知的克努森最小值的最小值。
The transient conductive heat transfer through a rarefied gas confined between two infinite parallel plates due to a sudden jump in the temperature of one of the plates is investigated in the whole range of the Knudsen number via kinetic theory. More specifically, the time-dependent heat transfer flow is modelled by the Holway kinetic model subject to diffuse boundary conditions. The governing integro-differential equation is numerically solved using the discrete velocity method in the molecular velocity space and typical finite control volume schemes in time and physical spaces. The time evolution of the density and temperature distributions as well as of the translational and rotational heat fluxes in terms of the two parameters characterizing the heat flow, namely the Knudsen number and the imposed temperature ratio between the plates is provided. The investigation is focused on the effect of the rotational degrees of freedom and a comparison between monatomic and polyatomic gases is performed. It is found that the time needed to reach the steady-state conditions varies between monatomic and polyatomic gases. In all cases the total time to recover the stationary solution in terms of the rarefaction parameter exhibits a minimum close to the well-known Knudsen minimum.