Water turbines are turbo machines utilizing 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 tube. 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. This apparatus is the model of a Francis turbine demonstrating the function of a reaction turbine. The apparatus consists of the Francis wheel, the control device with adjustable guide vanes, a band brake for loading the turbine and 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 measured by means of a band brake and is read on spring balances. For measuring the rotational speed, a non-contact techometer is used. A manometer shows the water pressure at the turbine inlet. The flow is detected by means of a stopwatch and a volumetric measurement in the Hydraulic Bench. The measured data make it possible to use the speed in order to determine the characteristic curves as power output, torque and efficiency. The experimental unit is positioned on the working surface of the Hydraulic Bench. The water supply is provided via Hydraulic Bench, alternatively, the experimental unit can be operated by the laboratory supply.