The End Correction in the Determination of Gas Viscosity by the Capillary Tube Method

Abstract

The voluminous data obtained for air from experiments on capillary tubes as flow meters have been used to test the formulae involving end-corrections, proposed by Brillouin and by Fisher. A measure of the validity of a given formula is obtained by assuming the value of the coefficient of viscosity and comparing the mass or gas transpired per second, as found experimentally, with the mass computed from the formula in question. The tubes employed in the tests ranged in size from very long lengths, where the end-effect was practically negligible, down to short lengths that they behaved as orifices.