## Abstract

The cylindrical Couette flow of a rarefied gas from macro- to micro-scales, in the case where the inner cylinder is rotating whereas the outer cylinder is at rest, is extensively investigated by direct simulation Monte Carlo (DSMC) code incorporated with a Volume-CAD software. The generalized soft sphere (GSS) model is applied to an intermolecular collision calculation. The diffuse reflection model and Cercignani-Lampis-Lord (CLL) model are used to model the molecule-surface interaction by considering the accommodation coefficients on inner cylinder (ACI hereafter) and outer cylinder (ACO hereafter) separately. The contents in this paper include following three aspects: I the flow field characteristics and force and torque on inner cylinder for eccentric Couette flow between different scales with same non-dimensional parameters (accommodation coefficients, eccentricity-clearance ratio, Knudsen number and Reynolds number) are compared; the flow field characteristics for different scales are same; with the increase of the scale, the total force on the inner cylinder increases slightly, while the torque is proportional to the scale; II the velocity profiles in concentric Couette flow under different non-dimensional parameters are studied; the result shows that the phenomenon of inverted velocity profile in the concentric Couette flow is only induced by a smooth outer cylinder; the non-dimensional tangential velocity, as well as its gradient is high at low Reynolds number; the Knudsen number has great impact on the tangential velocity profile, and the velocity profile may not be inverted in the case of low Knudsen number; III the flow field characteristics in eccentric Couette flow under different non-dimensional parameters are obtained; the recirculation zone may not appear when Knudsen number is high; the position of its center may be different depending on Reynolds number; with the increase of Reynolds number, the compressibility effect becomes important; stratified distribution of the density becomes obvious at low Knudsen number.

Original language | English (US) |
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Title of host publication | Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009 |

Pages | 469-475 |

Number of pages | 7 |

DOIs | |

State | Published - 2009 |

Event | 2009 ASME Fluids Engineering Division Summer Conference, FEDSM2009 - Vail, CO, United States Duration: Aug 2 2009 → Aug 6 2009 |

### Publication series

Name | Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009 |
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Volume | 2 |

### Conference

Conference | 2009 ASME Fluids Engineering Division Summer Conference, FEDSM2009 |
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Country/Territory | United States |

City | Vail, CO |

Period | 8/2/09 → 8/6/09 |

## All Science Journal Classification (ASJC) codes

- Fluid Flow and Transfer Processes
- Mechanical Engineering