Operating Principle of a Francis Turbine

Operating Principle of a Francis Turbine for Educational Laboratory.

Product Code:


 Operating Principle of a Francis Turbine

Transparent operating area1

* Turbine with adjustable guide vanes1

* Loading by band brake


Water turbines are turbomachines utilising water power. The Francis turbine is part of the reaction turbines which convert the pressure energy of the water into kinetic energy in the control device and in the impeller. The water is fed in the control device by means of a spiral housing. The flowing water is accelerated in the control device by the adjustable guide vanes and directed onto the vanes of the impeller. The redirection and further acceleration of the water in the impeller generates an impulse which is transmitted to the Francis wheel.

Operating Principle of a Francis Turbineis the model of a Francis turbine demonstrating the function of a reaction turbine.

The experimental unit consists of the Francis wheel, the control device with adjustable guide vanes, a band brake for loading the turbine and a housing with a transparent front panel. The transparent cover enables you to observe the water flow, the wheel and the guide vanes during operation. The angle of incidence and thus the speed of the impeller are modified by adjusting the guide vanes.

The turbine torque is determined by force measurement on a band brake and is read on spring balances. For measuring the rotational speed, a non-contact speed sensor, A manometer shows the water pressure at the turbine inlet.

The experimental unit is positioned on the working surface of the Base Module in a simple and safe manner. The water supply and flow rate measurement are provided. Alternatively, the experimental unit can be operated by the laboratory supply.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- design and function of a Francis turbine

- determination of torque, power and efficiency

- graphical representation of characteristic curves for torque, power and efficiency


1.  Function Of A Francis Turbine

2.  Transparent Front Panel For Observing The Operating Area

3.  Loading The Turbine By Use Of The Band Brake

4.  Adjustable Guide Vanes For Setting Different Angles Of Incidence

5.  Marking On Brake Drum For Non-Contact Speed Measurement

6.  Instruments: Spring Balances For Determining The Torque, Manometer Shows Pressure At Turbine Inlet

7.  Flow Determination Base Module

8.  Water Supply Using The Base Module Or Via Lab Supply

Technical Data


- output: 2,8W at n=1.000min-1, approx. 40L/min,


- Impeller, 7 vanes

Vane width: 5mm

External diameter: 50mm

- Guide vanes: 6 vanes, adjustable

Measuring ranges

- braking force (spring balance): 10N

- pressure: 0…0,6bar

Dimensions and Weight

LxWxH: 400x400x630mm

Weight: approx. 12kg

Required for Operation

Closed water circuit or water supply, drainage