Studies on the transport properties of fluids at high pressure : I. The viscosity of ammonia (The co-operative researches on the fundamental studies of the liquid phase reactions at high pressures)

Abstract

The viscosity of ammonia was measured at temperatures of 25, 50, 75, 100 and 125℃ over the pressure range from 1 atm to near the saturation pressure, using the oscillating disk method. Also, an experiment at 135℃ was carried out only to see the initial density dependency of the viscosity of ammonia. The accuracy of the measurements is estimated to be ±0.3%. It is found that at 25, 50 and 75℃ the viscosity of ammonia shows a steady decrease with an increase in pressure (or density), and that at 100 and 125℃ it passes through a minimum. The data were fitted to the polynomials of density at each temperature investigated. The coefficient of the first order density term in the equation, which indicates the degree of the initial density dependency, shows a decrease in its absolute value with an increase in temperature under the present experimental conditions and becomes zero at about 135℃.