Flow through Capillary Tubing with Eccentric Annular Sections

Abstract

Gas flow through capillaries obstructed by wire inserts was investigated for ratios of core to capillary diameters (B/A's) of 0.08 to 0.9. For a given core‐capillary combination, laminar and turbulent as well as an intermediate region are well defined. Deviations from Poiseuille flow for the range of B/A's are presented in a working curve, which will give flow rates for laminar flow correct to from 5 to 10%. The pressure drop vs flow curves for the intermediate and turbulent flow regions are reasonably reproducible. The use of the cored capillary for very small leak rates looks especially attractive because, with large B/A's such that the maximum crescent clearance is less than 0.25 mm, the onset of turbulence is postponed to much higher pressure drops.