The Francis turbine belongs to the reaction turbines which convert pressure energy of the working medium into kinetic energy in the guide vanes and in the rotor. Francis turbines are used for medium heads. The turbine power is controlled by adjusting the guide vanes. In practice, Francis turbines are used in run-of-river power plants and in pumped storage plants.
It enables examinations of the function and operating behaviour of a Francis turbine. The dimensions of the trainer guarantee realistic measured values. The closed water circuit consists of a tank with optional cooling, a centrifugal pump and a flow control valve for adjusting the inlet pressure. The transparent operating area of the turbine enables an optimal view of water flow, rotor and guide vanes during operation. By adjusting the guide vanes the angle of attack, the cross-section and thus the output of the turbine are changed. An asynchronous machine is used as a generator for loading the turbine. A pump with variable speed via frequency converter provides for an energy efficient operation.
Learning Objectives And Experiments
- Investigation of the conversion of hydraulic into mechanical energy
- Determination of the mechanical power and hydraulic power of the turbine
- Determination of efficiency
- Recording of characteristic curves
- Investigation of the influence of the guide vane position
- Velocity triangles
Specification
- Investigation of a Francis turbine
- Closed water circuit with pump, motor, flow control valve and tank with optional cooling
- Pump with variable speed via frequency converter
- Adjustment of flow rate via flow control valve
- Loading the turbine by use of the asynchronous machine as generator
- Rotor and guide vanes of the turbine completely visible
- Adjustable guide vanes for setting different angles of attack
- Non-contact speed measurement at the generator haft and force sensor for measuring the driving torque
- Digital display for temperature, flow rate and ressures (additional manometer within scope of supply), speed, torque and electrical power of generator
Technical Data
- Francis turbine
- Hydraulic power: 2,1kw at 1500min-1
- Mechanical power: approx. 1,4kw at 1500min-1
- Rotor, D: 120mm, 15 blades
- 10 guide vanes, angle of attack adjustable: 0…23°
- Centrifugal pump, multistage
- Variable speed
- Power consumption: 5,5kw
- Max. Flow rate 900L/min
- Pump head 42m
- Asynchronous machine as generator
- Output: 2,2kw at 1440min-1
- Tank: 550L
- Measuring ranges
- Temperature:: 0…100°C
- Pressure (inlet): ±1bar (turbine)
- Pressure (outlet): 0…6bar (turbine)
- Flow rate: 0…1000L/min
- Torque: 0…20Nm
- Speed: 0…3000min-1
- power: 0…2200W (generator)
- 400V, 50Hz, 3 phases
- 400V, 60Hz, 3 phases, 230V, 60Hz, 3 phases
