Knudsen compressors are devices without any moving parts that use the nanoscale phenomenon of thermal transpiration to pump or compress a gas. Thermal transpiration takes place when a gas is in contact with a solid boundary along which a temperature gradient exists. If the characteristic length scale is on the order of, or smaller than, the molecular mean free path, then the gas flows from cold...

in this paper, fluid flow between two parallel flat plates that are partially filled with two-dimension porous media is investigated numerically using single relaxation time (srt) lattice boltzmann method (lbm) at pore scale. the considered obstacles are random, circular, rigid and granular with uniform diameters. single component and single-phase viscous newtonian fluid are considered as worki...

A complete mathematical description of oscillatory Couette flows within the framework of kinetic theory is not available in the literature. Motivated by this and their vast engineering applications, we present a parametric study of time-periodic oscillatory Couette flows using the unsteady direct simulation Monte Carlo ~DSMC! method. Computations are performed as a function of the Knudsen ~Kn! ...

Accurate evaluation of damping in laterally oscillating microstructures is challenging due to the complex flow behavior. In addition, device fabrication techniques and surface properties will have an important effect on the flow characteristics. Although kinetic approaches such as the direct simulation Monte Carlo (DSMC) method and directly solving the Boltzmann equation can address these chall...

A unidirectional flow of a rarefied gas between two parallel plates driven by a uniform external force is investigated on the basis of kinetic theory with special interest in the behavior in the near continuum regime. The Bhatnagar-Gross-Krook (BGK) model of the Boltzmann equation and the diffuse reflection boundary condition are employed as the basic system. First, a systematic asymptotic anal...

Hypersonic rareŽ ed-gas  ows near two side-by-side plates have been studied numerically with the direct simulationMonte Carlo technique under transitional rareŽ ed-gas- ow conditions (Knudsen numbers from 0.024 to 1.8). Strong in uences of the geometrical factor (ratio of distance between plates to plate length) and the Knudsen number on the  ow structure (the shape of shock waves, the conŽ...

In this study, the effect of small-scale of both nanostructure and nano-fluid flowing through it on the natural frequency and longitudinal wave propagation are investigated. Here, the stationary and axially moving single-walled carbon nanotube conveying fluid are studied. The boundary conditions for the stationary nanotube is considering clamped-clamped and pined-pined and for the axially movin...

Due to its intrinsically kinetic nature, lattice Boltzmann (LB) approach to simulating non-equilibrium gas flows has recently attracted significant research interest. Compared with other kinetic methods, it can offer a significantly smaller computational cost. To capture the nonlinear high-order rarefaction phenomena in gas flows, a geometry-dependent gas local mean free path has been proposed ...