A online capillary method for viscosity measurement under high temperature and pressure

A online capillary method which can be used to measure the viscosity of fluid at high temperature and pressure is provided, and the measurement system which can measure the viscosity of fluid at temperature and pressure up to 773 K and 30 MPa by connected with high temperature and pressure circulation system was designed and constructed. Viscosities of pure water have been measured at four isobars(12, 23, 25, 28 MPa) and temperatures between 303.46 K and 383.28 K. The absolute average of relative deviations between the measurement results and the data from NIST database is 2.01%, which show the accuracy and reliability of the experimental system.