Francis Turbines
Reaction turbine — medium-head applications
Francis turbines are reaction turbines generally considered for medium-head applications across a wide flow range. Water enters a spiral casing, passes through a stay ring and adjustable guide vanes, and flows radially inward through the runner before exiting axially through the draft tube.
Turbine photograph
to be supplied
Typical Applications
- Medium-head small and medium hydropower schemes
- Sites with moderate to high design discharge
- Plants requiring compact equipment at significant output
- Refurbishment and runner replacement projects
Operating Principle
Water under pressure fills the spiral casing and is directed by the guide-vane cascade onto the runner. Both pressure energy and kinetic energy are converted as the flow passes through the runner passages. Guide-vane opening regulates discharge and output, coordinated by the governor.
Main Components
- Spiral casing and stay ring
- Guide vanes and regulating mechanism
- Francis runner
- Draft tube
- Main shaft, bearings and coupling
- Seals, wearing rings and auxiliaries
Configurations
- Horizontal shaft arrangements for compact small-hydro units
- Vertical shaft arrangements with generator above the turbine
- Arrangement selected according to head, discharge, setting and powerhouse layout
Generator & Control-System Integration
Governor and hydraulic-system matching, generator and excitation integration, protection and control, and draft-tube and setting coordination including cavitation assessment.
Technical specifications, ratings and dimensions are prepared per project following review of site data. No performance figure on this page constitutes a guaranteed value.