Design of the measurment setup for the friction torque and axial load on the Francis turbine test rig
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Hydropower laboratories are used to determine the hydraulic performance of model turbines, which can then be used as an indication of expected prototype operation. The rules and guidelines for performance of complete model tests are provided by the international IEC 60193  standard. An important part of model testing is the determination of turbine shaft torque and axial forces. The objective of this thesis is to design a system for measurement and calibration of friction torque and axial load on the Francis turbine test rig for both the Waterpower Laboratory at NTNU and the Turbine Testing Laboratory at Kathmandu. The systems must comply with the requirements of IEC 60193 . The friction torque measuring system at the Waterpower Laboratory is based on the existing setup, with a load cell attached to an arm, sensing the torsional movement of the bearing cover. A linear stepper has been introduced to the design, to counteract the frictional forces of the membrane. The system has been evaluated for total systematic uncertainty. Pressure taps inside the hydrostatic bearing are used to measure axial forces acting on the Francis turbine at the Waterpower Laboratory. A design has been developed for calibration of the pressure transducers, able to perform calibration of forces in both axial directions. Stress analysis are performed on the consisting parts, and total systematic uncertainty of the setup is determined. For the Turbine Testing Laboratory, the friction torque and axial loads are measured with silicon strain gauges. The existing shaft and bearing design has been modified to fit the space requirements of the measurement setups. A telemetry system is utilized for wireless transmission of the signal. 3D model of the Francis turbine test rigs at both Waterpower Laboratory and Turbine Testing Laboratory are developed. Detailed machine drawings of the measurement setups are presented in this thesis.