USING FALLING FILM FLOW TO MEASURE THE VISCOSITY OF THE LIQUID

An experimental device for measuring liquid viscosity coefficient was designed and built by using falling film flow. The model was modeled according to the N-S equation of incompressible liquid and combined with boundary conditions. The thickness of liquid film is calculated by measuring the surface velocity of liquid film. The viscosity coefficient of castor oil was measured at different flow rates. The relative accuracy of viscosity coefficient measured at different dip angles was basically the same, and the relative error was below 8%. The application conditions and error sources of the device are analyzed. The thickness of liquid film was compared and verified by total internal reflection method. This study enriches the teaching content and method of measuring liquid viscosity coefficient, helps students to master relevant knowledge of fluid mechanics and improve comprehensive design ability.