An improved corresponding states principle model for orthohydrogen thermal conductivity from the triple point to 300 K and 20 MPa.

There is a notable scarcity of reference data on the thermal conductivity of orthohydrogen in both vapor and liquid phases within the open literature, compared to parahydrogen and normal hydrogen. An improved corresponding states principle (CSP) model is proposed to predict the thermal conductivity of orthohydrogen by employing an optimized shape factor, which is expressed as a correlation with respect to pressure and temperature from the triple point to 300 K and at pressures up to 20 MPa. Critical parameters, ideal state thermal properties, and eccentricity factor are involved in the calculation as input parameters. The feasibility and accuracy of the proposed CSP model is verified by using experimental data of parahydrogen and some theoretical data of orthohydrogen. The estimated uncertainty of the model against high-precision experimental data of parahydrogen is within ±2.82 %. When the model is applied to dilute gas orthohydrogen, the predictions exhibit a deviation of less than ±5 % compared to other methods found in the literature. In addition, a correlation for thermal conductivity of parahydrogen, presented as a single function of temperature, is also proposed along the vapor-liquid equilibrium at temperatures from the triple point to the critical point, with an uncertainty of ±3 %. [ABSTRACT FROM AUTHOR]