An experimental study of turbine meter calibration curves with various viscous fluids

The accuracy of the turbine meter is influenced by the measured medium and its changing kinematic viscosity. Predictability and consistency of calibrating meter factor against volume flow rate are unable to be achieved with various viscous liquids. The method of dimensional analysis is applied to derive Reynolds and Strouhal numbers to describe the performance of the turbine meter. A DN25 turbine meter is calibrated with five different mixtures of propylene glycol and water, respectively. The comparison results show that the calibration data for varied kinematic viscosity vary up to 0.9% at Reynolds number lower than 7 400. The scattered calibration curves tend to be collapsed as the Reynolds number increases, and the calibration data vary less than 0.1%. The rise of skin friction drag occurs at the boundary layer transition from laminar flow to turbulent flow on the rotor blade surface, which is responsible for a hump-shaped calibration curve. When the kinematic viscosity is lower, the hump is flatter. The bearing static drag is the main reason for scattered meter factors, and the discrepancy tends to increase with decreasing Reynolds number. Therefore, the turbine meter should not be used for low Reynolds numbers when the kinematic viscosities of the calibration medium and the working medium are significantly different. © 2022, Science Press. All right reserved.