Capillary constant and surface tension of methane–helium solution

•The capillary constant a2 of methane–helium solutions has been measured at T = 95 − 175 k and p up to 4 MPa.•Surface tension σ and adsorption have been calculated.•Equations describing temperature, pressure, composition dependences of a2 and σ are proposed.

The differential capillary method has been used to measure the capillary constant a2 of methane–helium solutions in the temperature range from 95 to 175 K at pressures up to 4 MPa. The surface tension γ and adsorption have been calculated from the obtained values of a2 employing, in addition, literature data on the density of the liquid and vapor phases of the respective solutions. Equations, which approximate the temperature, pressure and concentration dependences of a2 and γ, are proposed.

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