• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>4th International Conference on Nanochannels, Microchannels and Minichannels 2006(ICNMM2006) pt.A >SCALED NAVIER-STOKES-FOURIER EQUATIONS FOR GAS FLOW AND HEAT TRANSFER PHENOMENA IN MICRO- AND NANOSYSTEMS
【24h】

SCALED NAVIER-STOKES-FOURIER EQUATIONS FOR GAS FLOW AND HEAT TRANSFER PHENOMENA IN MICRO- AND NANOSYSTEMS

机译：微尺度和纳米尺度中气体流动和传热现象的尺度Navier-Stokes-Fourier方程

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A new hydrodynamic model is proposed in order to model critical phenomena in gas flows at the micro- and nanoscale. A scaling is applied to the conventional Navier-Stokes-Fourier equations, mathematically equivalent to using an "effective" viscosity and an "effective" thermal conductivity in the original linear constitutive relations. Expressions for this "effective" viscosity and this "effective" thermal conductivity are obtained from two ideal half-space flow problems: Kramer's problem, and the temperature jump problem. Our model ensures the correct viscous stress is maintained in the region of the wall in isothermal flow (or the correct heat flux in the pure heat transfer situation); it is only the relationships between stress and the corresponding near-wall strain-rate, and between heat flux and the near-wall temperature gradient, that are altered. The advantage of our model over the traditional linear hydrodynamic model is that the non-equilibrium flow in the Knudsen layer is described. Its advantage over higher-order hydrodynamic models for rarefied gas flows is that no additional boundary conditions are required (although there are minor changes in the slip/jump coefficients), so modifications of current CFD codes to incorporate this new model would be minimal. As an application example, we solve for the velocity profiles and drag force on a micro-sphere moving in a gas at different Knudsen numbers (Kn). For this problem, our model gives excellent results for Kn<0.1 and accptable results up to Kn=0.25: this is considerably better that the tradition Navier-Stokes model with non-scaled constitutive relations.
机译：提出了一种新的流体动力学模型，以便在微观和纳米尺度上模拟气流中的临界现象。将比例缩放应用于常规的Navier-Stokes-Fourier方程，在数学上等同于在原始线性本构关系中使用“有效”粘度和“有效”导热系数。这种“有效”粘度和这种“有效”导热系数的表达式是从两个理想的半空间流动问题得出的：Kramer问题和温度跳跃问题。我们的模型确保在等温流中在壁区域中保持正确的粘性应力（或者在纯热传递情况下保持正确的热通量）；只有应力和相应的近壁应变率之间的关系以及热通量和近壁温度梯度之间的关系才会改变。与传统的线性流体动力学模型相比，我们的模型的优势在于可以描述Knudsen层中的非平衡流。与稀有气体流动的高阶流体力学模型相比，它的优点是不需要附加的边界条件（尽管滑移/跳跃系数有微小变化），因此对当前CFD代码进行修改以合并该新模型将是最小的。作为一个应用示例，我们求解了以不同克努森数（Kn）在气体中移动的微球上的速度分布和阻力。对于这个问题，我们的模型对于Kn <0.1给出了出色的结果，并且可支持的结果高达Kn = 0.25：这比具有非比例本构关系的传统Navier-Stokes模型好得多。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号