Turbine runners

We are experienced supplier of turbine runners. All of our runners are based on proven designs and CFD calculations. Our expertise are Francis, Pelton, Kaplan and Diagonal/Deriaz runners. Every case is treated separately to avoid potential problems - to increase turbine efficiency, improve cavitation resistance, minimize sand erosion... We have also the know-how for developing and designing the turbine runners for existing turbines refurbishment, which can fit to the existing turbine, without other modifications. For such cases, we can also adapt the turbine optimum discharge point and  net head, even if it was dimensioned improperly in the past.

We have successfully delivered many runners for well known European turbine companies. For more information, please contact us.

Pelton turbine - from design to runner

High efficiency Pelton runner, machined from one forging piece

Francis runner

Kaplan blade

CFD Analysis and optimization

Computational fluid dynamics (CFD) is used to analyze and to solve problems related to fluid flow. The cases are complex and thus computers perform a huge amount of iterations. Boundary conditions precisely define the problem we want to solve. Our aims are e.g. to predict the performance and cavitation characteristics and to reduce losses in various parts of turbines.

The governing equations to be solved are the Reynolds - Stress averaged Navies-Stokes equations. The spatial discretization of the flow domains is performed using various meshing tools for grid generation. Also discretization of equations must be performed, this means defining a numerical scheme. Time-depending or steady flows can be simulated.

When the solution is obtained we use post-processing tools for visualization and analysis of computed flow field.


By using CFD simulations we reduce costs and time by using fast computers instead of time consuming experimental measurements. Of course calculations must be verified with tests on physical models.


Optimization of a new Runner (HPP Untere Sill, Austria, 10.5MW)

Development of new Diagonal turbine runner (HPP Vagna)

Optimizig the runner blades for Saxo turbine (HPP Lower White River, Canada, 520kW)

Development of new Francis runner with very high specific speed (HPP Imatra, Finland, 38MW)

Pressure distribution on a optimized Francis turbine blade (HPP Sinni, Italy, 3MW)


Small hydro

We offer complete water to wire solution for small hydro power plants up to 5MW.  Supply includes turbine, generator, main inlet valve (MIV), automated controls and switchgear. We offer complete custom system design. Thus we can improve efficiency to shorten payback period, minimize the civil works costs, and meanwhile assure short delivery times. Solutions are proven, simple and up-to-date - this ensures smooth operation, low operation costs and long lifetime.

Selection of turbine type

The net head and available discharge determines the type of the turbine. Depending on the operation principle, there are two general classifications - impulse and reaction turbines. Reaction turbines are Kaplan, Francis and Diagonal type, impulse are Pelton type.

Francis turbines are appropriate solution for medium heads. Francis runners have fixed runner blades, usually 11 or more. The discharge is regulated with the guide vanes. Operating range is approximately from 40% to 100% of rated discharge. Turbine peak efficiencies are up to 95%, depending on turbine type and size. Types:

-Horizontal or vertical shaft

-Spiral or open flume

-Runners mounted directly on the generator shaft or with turbine shaft

Kaplan turbines are appropriate solution for low heads. Kaplan runners have fixed or adjustable runner blades, from 3 to 6. Guide vanes can be fixed or adjustable, depending on the size and fluctuations of discharge. Operating range is approximately from 30% to 100% of rated discharge. Turbine peak efficiencies are up to 94%, depending on turbine type and size. Types:

-Vertical propeller (spiral or open flume), Pit turbines, Bulb turbines, S-turbines, Saxo turbines,

-Fixed or adjustable blades runners

-Fixed or adjustable guide vanes

Pelton turbines are appropriate solution for high heads. Pelton runners have have usually 17 buckets or more. The discharge is regulated with nozzles, from 1 to 6. Operating range depends on the number of nozzles. Turbine peak efficiencies are up to 92.5%, depending on turbine type and size. Types:

-Horizontal type (from 1 to 3 nozzles)

-Vertical type (from 3 to 6 nozzles)

Diagonal turbines are appropriate solution for similar conditions as Francis turbines. Diagonal turbine are double regulated, similar as Kaplan turbines. The main advantage comparing to Francis turbines are smoother and more efficient operation over a wider range of head and discharge.


Based on years of experience on hydropower, we offer consulting. Our consulting services includes:


Selection and dimensioning of water turbines

Energy production calculations

Waterhammer analysis and turbine overpressure

Stress analysis

Vibration analysis



All Rights Reserved, Copyright © 2015