Ph = ρ g Q HPh: W; ρ: kg/m³; g: m/s²; Q: m³/s ; H: m of net fall.
Use when: Permanent regime; use the fall after hydraulic losses.
Francis turbine
Link head height, flow rate and useful hydraulic power.
What is happening?
A Francis turbine is a mixed-flow reaction turbine. The distributor regulates the intake to the wheel; the diffuser contributes to energy recovery at the output.
The efficiency compares the power obtained to the hydraulic power available. The best operating point depends on the type of impeller, speed and settings: maximum flow does not automatically ensure the best performance.
The formulas, with their conditions.
Putile = η ρ g Q Hη: dimensionless overall efficiency.
Use when: Define whether the useful power is mechanical or electrical, and use the corresponding efficiency.
Where is this principle used?
Hydroelectric power station
Intermediate fall and flow domain, depending on the design: dam power plant or hydroelectric development.
Turbomachinery industry
Sizing and controlling production groups.
What to observe in the experiment
Modify the opening of the distributor and monitor flow, power and efficiency.
References and readings
This sheet explains the principles and their assumptions. Educational simulation can simplify the process; an industrial model requires suitable data and validation.
Have you understood the essentials?
Only one correct answer per question. Answer all three questions, then view the answer key.
Intu Lab · Understanding sheet · Kimba Christian