Correlation for the Viscosity of Normal Hydrogen Obtained from Symbolic Regression

We report the results of a symbolic-regression methodology to obtain both the functional form and the coefficients for a wide-ranging correlation for the viscosity of normal hydrogen. The correlation covers the temperature range from the triple-point temperature to 1000 K and pressures up to 200 MPa and extrapolates in a physically reasonable manner to 2000 K. The estimated uncertainty is 4 % for the saturated liquid from the triple point to 31 K, with larger deviations as the critical region is approached. The estimated uncertainty is 4 % for the supercritical fluid phase at pressures to 200 MPa. For the limited range of 200 K to 400 K at pressures up to 0.1 MPa, the uncertainty is 0.1 %.