Viscosity of Nitrogen, Helium, Neon, and Argon from —78.5° to 100°C below 200 Atmospheres

A new capillary-flow viscometer has been developed for the measurement of the absolute viscosity of gases as a function of temperature and pressure. In the viscometer a steady flow of gas is maintained through a capillary of known dimensions, and the pressure difference developed across the capillary is measured as a function of the flow rate. From these measurements there are obtained by extrapolation to zero flow rate the absolute viscosity and information on the deviation from Poiseuille flow. The viscosities of nitrogen, helium, neon, and argon have been determined in this viscometer from —78.5° (—50° for helium and neon) to 100°C and up to 200 atm. The experimental results are believed to be accurate within 0.1%. Agreement with previous results, where available, is generally satisfactory. All the viscosity data for each gas can be represented adequately by the sum of two functions, one dependent on temperature only, the other dependent on density only.