Thermal conductivity of gaseous and liquid ammonia

The thermal conductivity of gaseous and liquid ammonia has been measured in the range 300-300 K and at pressures up to 50 MPa. The measurements were a necessary preliminary to a fitting of the thermal conductivity surface in the density-temperature plane, which is part of the current program of the Transport Properties Subcommittee of the I.U.P.A.C. Results were obtained that are believed to be accurate to 2 percent. It is difficult to make a good comparison of these results with previous data until a full correlation of the thermal conductivity of ammonia is carried out. A preliminary assessment for the liquid phase indicates that agreement is reasonable over much of the range with differences up to around 5 percent under certain conditions.