Measurements of the viscosity of compressed gaseous and liquid methane

The shear viscosity coefficient of compressed gaseous and liquid methane has been measured at temperatures between 100 and 300 K and at pressures up to 30 MPa (4350 psia) with a torsionally oscillating quartz crystal viscometer. The estimated precision and accuracy of the measurements are about 0.5% and 2%, respectively. The measurements have been compared with an equation previously proposed for calculating the viscosity of gaseous and liquid methane. Most of the differences between the equation and the measurements reported here are within our experimental error. Larger differences (up to 6%) are reported at the lowest temperature (100 K) and high pressures, and along a supercritical isotherm at 200 K (T ≈ 1.05 T_c).