The viscosity of nitrogen-ammonia system under pressures

Abstract

The viscosities of nitrogen, ammonia and their mixtures have been measured by the use of an improved oscillating disk type viscometer at the temperatures of 25, 50, 75 and 100℃, and in the pressure range, up to about 120×10^5 Pa for nitrogen and up to around the saturated vapor pressure of ammonia for both ammonia and nitrogenammonia gaseous mixtures. The accuracy of the measurements is estimated to be within ±0.3%. The initial pressure (density) dependence of the viscosity of ammonia and nitrogenammonia mixtures, that is, η_0^-1(∂η/∂P)_P→0 (or η_0^-1(∂η/∂p)_p→0) where η is the viscosity of gases, η_0 is the viscosity extrapolated to zero pressure (or density), P is pressure and p is density, changes its sign from negative to positive with an increase in not only temperature but also the mole fraction of nitrogen.