Viscosity Measurement of Liquid Propane, n -Butane and i -Butane at Temperatures from 135 to 225 K and Pressures up to 10 MPa

Viscosity plays a crucial role in the simulation of liquefaction and the design of fluid machinery for Liquefied natural gas engineering. In our previous work, the viscosities of methane, ethane, and nitrogen─components of liquefied natural gas─have been measured [Zhou, X.; et al.; Viscosity Measurements of Nitrogen and Argon at Temperatures from 90 to 200 K and Pressures Up To 5 MPa. Int. J. Thermophys.2024, 45, 3010.1007/s10765-023-03325-9.;Zhou, X.; et al.Viscosity of methane and ethane at temperatures from (100 to 225) K and at pressures up to 10 MPa. Fuel2026, 404, 13622710.1016/j.fuel.2025.136227. ]. The present study measures the viscosity of compressed liquid propane, saturated liquid n-butane, and compressed liquid i-butane using the vibrating-wire method at temperatures between 135 and 225 K and pressures up to 10 MPa. The relative combined standard uncertainty is estimated to be 1.16% over all temperature and pressure ranges. The present results and literature data were compared with the reference correlations. The present results are in good agreement with the reference correlations within 2%.