Kaplan Low-Head Hydro Turbine Sizing Calculator
Calculate Kaplan axial-flow turbine runner diameter, blade tilt angle, guide vane opening, axial hydraulic thrust, and MW power output per IEC 60193.
Low-Head Flow & Operating Head
Runner Hub & Blade Regulation
Kaplan Runner Dimensions & Power
| Runner Outer Diameter (D): | -- m |
| Runner Hub Diameter (d_hub): | -- m |
| Annular Water Flow Area (A_flow): | -- m² |
| Axial Flow Through Velocity (Va): | -- m/s |
| Blade Tip Peripheral Speed (u_tip): | -- m/s |
| Axial Hydraulic Thrust on Bearing: | -- kN (-- tonnes) |
| Specific Speed (ns metric): | -- |
Recommended Tools & Equipment
Tested hardware and components for high reliability
Frequently Asked Questions
What is the fundamental difference between a propeller turbine and a Kaplan turbine?
A fixed-propeller turbine has stationary blades, achieving high efficiency only at its exact design point (efficiency plummets if river discharge drops by 20%). In contrast, Viktor Kaplan's 1913 invention introduces "double-regulation": the runner blades are pitched continuously by internal oil-hydraulic servomotors to match the exact angle of the wicket gates, maintaining peak 90%+ efficiency across wildly fluctuating seasonal river flows.
Why are Kaplan turbines used exclusively for low-head high-flow sites?
Axial-flow Kaplan turbines operate at very high specific speeds (ns between 400 and 1000). At heads below 40 meters, large water volumes (hundreds of cubic meters per second) must pass through the powerhouse. An axial path through propeller blades handles massive volume flows with compact runner diameters that would choke a radial Francis wheel.
What creates the massive vertical thrust load on Kaplan turbine bearings?
Water flowing vertically through the propeller exerts high hydrostatic and dynamic pressure drop across the runner disk. For a 4-meter diameter runner under 20 meters of head, the downward axial hydraulic thrust easily exceeds 200 to 500 metric tons, requiring massive Kingsbury or Michell tilting-pad thrust bearings bathed in pressurized oil.