Knudsen Number

Modified N-S equations have been used to study the stability of microflow with a not-too-large Knudsen number .

研究了克努森数不是特别大的微流动的稳定性，这种流动处于N-S方程适用的临界处。

By adjust the momentum coefficient and thermal coefficient , the two important parameters in boundary conditions , the new model is valid as long as the Knudsen number is less than 1.2 .

通过调整边界条件中的重要参数切向动量协调系数σv和热量协调系数tσ的值，可以将新建模型的应用范围扩大到克努森数Kn<1.2的稀薄气体流动中。

Smaller vapor Knudsen number results in higher velocity and lower relative vapor temperature .

蒸气的Kn越小，蒸气的速度越高，相对温度越低；

We get its initial layer solutions and boundary layer solution for small knudsen number .

又从正规解出发得到了没有久期项的初始层解并讨论了具有小knudsen数的边界层解。

Analysis the Low Knudsen Number Rarefied Flow Fields

小Knudsen数稀薄气体绕流流场分析

A kind of singular perturbation method for solving the Boltzmann equation with small Knudsen number

具有小Knudsen数的Boltzmann方程的奇异扰动解法

When Knudsen number exceeds 0.0045 , results of the continuum model obviously deviate from these of the kinetic .

当努森数大于0.045时，连续介质模型与分子运动模型模拟结果差异较大。

The Knudsen number varies from 0.05 to 1.00 and covers the slip , transition , and free molecule regions .

所模拟流动的Knudsen数的范围是005～100，涉及了滑移区、过渡区和自由区。

Judging with Knudsen number , the flow regime in the micro gas bearing is slip regime instead of the continuum regime .

根据气膜厚度的Knudsen数，确定滑移流为微型气浮轴承内部的润滑机制。

The focal point was put on the changes of physical parameters of atomic vapor during the changes of atomic evaporation characteristics and of Knudsen number .

着重研究了原子蒸气束空间自由蒸发的特性以及Knudsen数（Kn数）变化时，蒸气原子物理参数的变化。

The reference Knudsen number is defined for micro gas journal bearings and its value range is obtained according to the viscosity data of air at different temperatures .

针对微气体轴承给出参考努森数的定义，根据空气不同温度时的黏度，得到参考努森数的分布范围；

In article [ 3 ] , the author discussed the normal solution of the Boltzmann equation for small knudsen number with a kind of singular perturbation method .

在文章[3]中，作者用奇异扰动解法讨论了具有小knudsen数的Boltzmann方程的正规解。

Considering the general nonlinear Boltzmann equation , a uniform algorithm has been developed to simulate rarified flows at a wide Knudsen number range numerically .

从一般非线性Boltzmann方程出发，发展并实现了一套适于大范围Knudsen数稀薄流问题数值模拟的统一算法。

The current work tends to explain this results as a result of gas flow slip effect within such micro pore structure and predict the permeability relationship with Knudsen number .

尝试将这一结果归结为气体在微细通道中渗流时出现稀薄性效应的影响，提出了渗透率与Kundesn数的关系式。

One can carry out gradient expansion for energy-momentum tensor and charge currents , or equivalently expansion in powers of the Knudsen number .

一般而言，能动量和粒子流可以作梯度展开，或者以Knudsen数来展开。

The Knudsen number is defined as the ratio of the macroscopic length scale ( hydrodynamic wave-length ) to the microscopic one ( mean free path ) .

Knudsen数的定义是：宏观的特征长度与微观特征长度（一般为平均自由程）之比。

Partial distribution of the flow field is given and the influence of the Knudsen number and Mach number on the drag coefficient and the pressure coefficient distribution curves of the surface are also presented .

给出了流场部分特征分布，考察了不同Knudsen数、不同马赫数对表面压力系数和阻力系数的分布的影响。

It is different with the traditional DVM . And comparing this model with theory analysis and numerical solution , in the low speed flow , it shows excellent agreement when Knudsen number from slip region to transfer region .

将这种模型与数值模拟和理论分析结果的对比表明，离散模型不仅能够模拟低速流动问题，而且还能够模拟Knudsen数从滑移领域到过渡领域内的气体流动，并且计算速度快。

When the Knudsen number is between 10 ~ ( - 3 ) and 10 ~ ( - 1 ), the gas rarefaction effect causes relative slip of flow and jump of temperature to the tube wall .

当Knudsen数处于10-3和1-01之间时，稀薄效应造成气体与管壁面间的相对滑移和温度跳跃。

In addition , the application of LBE to the microscopic gas flows still has two critical problems , that is , the relation between relaxation time and Knudsen number , another is the boundary treatment of LBE .

另外，在微尺度传热传质问题的研究中，LBM刚刚起步，还存在两个关键问题需要解决，即松弛时间与Knudsen数之间的关系以及LBM的边界处理问题。

The numerical results show that the kinetic BGK with slip boundary condition can obtain the drag coefficient , which is well agreement with the experimental data till Knudsen number up to 0.3 , and can simulate the continuum-transition flow .

计算结果表明：采用滑移边界条件，直到克努森数为0.3，计算得到的阻力与实验都符合得很好。因此，采用BGK算法加滑移边界条件，能够模拟由连续流到近连续区的流动。

The hot-dip-depth and temperature difference between fluid and platelet wall are influenced by many factors , such as the coefficient of heat conductivity of platelet and fluid , the coolant fluid , the Knudsen number , and so on .

热浸深度、流体与层板壁面的温差大小要受层板的导热系数、冷却剂流量及流动的Kn数等因素的影响。

In this paper , we use a kind of singular perturbation method to find the normal solution of the Boltzmann equation with small Knudsen number . It is proved that the secular terms may be removed by improving the Hilbert expansion and Enskog expansion .

本文用奇异扰动方法讨论了具有小Knudsen数的Boltzmann方程的正规解，证明把Hil-bert展开和Enskog展开加以改进可以消除久期项。

And further the effects of Knudsen number , Prandtl number , thermal conductivity , thermal accommodation coefficient and gas pressure on the gas gap conductance are discussed , which provides the quantitatively theoretical solutions to the interfacial gap gas heat transfer in the real contact conditions .

并对影响接触界面间隙热导的克努森数、普朗特数、热导率、适应系数、压力等参数进行了分析，为实际情况下接触界面的传热提供了理论基础。