Free Molecular Flow through a Conduit with an Orifice

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

Hideo Shinagawa¹  Kikuo Okuyama¹  Hiromichi Nakamura¹ 

[1] Department of Chemical Engineering, Hiroshima University

关键词: Free Molecular Flow;    Monte Carlo Method;    Orifice;    Cylindrical Tube;    Transmission Probability;   

DOI  :  10.1252/jcej.30.38

来源: Maruzen Company Ltd

【 摘 要 】

References(7)Cited-By(1)The transmission probabilities and the number of molecules reflecting from the wall were computed using a Monte Carlo method for free molecule flow through a conduit containing an orifice of zero thickness. The computed transmission probabilities were compared with a composite transmission rule and a series-resistance equation. The distribution of the molecular number density on the conduit wall along the conduit axis was determined by assuming that the ratio of the molecular number flux reflecting from the conduit wall to that entering into the conduit inlet corresponds to the ratio of the molecular number densities at each position. When the orifice was placed halfway down the length of the conduit, the composite rule and the series-resistance equation, respectively, agreed well with the computed transmission probabilities for the conduits with the aspect ratio L/R ≥ 10, and the cross-sectional area ratio of tube and orifice opening β ≥ 10, and for the conduit with β ≥ 40. The molecular number density distributions were symmetric with respect to the midpoint, and had a minimum in the upstream side and a maximum in the downstream side. The molecular number density distributions exhibited jumps across the orifice, as well as at the inlet and exit of the conduit.

【 授权许可】

Unknown