DESCRIPTION

Technical Description

The core piece of the experimental plant is the axial turbomachine with attached asynchronous motor. It can be operated either as a pump or turbine. To this end, different rotors /impellers and stators / guide vane systems are used. Included in the scope of delivery are four rotors / impellers and four stators / guide vane systems supplied with different blade / vane angles. The experimental plant contains a closed water circuit with expansion tank and centrifugal pump. The compressed-air powered expansion tank allows the turbomachine to be converted without loss of water.

The asynchronous motor functions during turbine operation as a generator, and during pump operation as a drive. A powerful pump generates flow and pressure during turbine operation. The power that is generated by the turbine is fed  into this pump.

The transparent housing allows a full view of the rotor / impeller and stator / guide vane system and flow processes. The 3-hole probe can be used to measure the direction and velocity in the flow field directly upstream of, between, and downstream of rotor / impeller and stator / guide vane system. These values are used to record the velocity triangles for the blade / vane shapes.

Operation under different pressure levels is possible in order to study cavitation. 

The speed is detected contact-free by means of an inductive displacement sensor on the motor shaft. To determine the drive power, the asynchronous motor is mounted on swivel bearings and equipped with a force sensor to measure the drive torque. Manometers measure the pressures at inlet and outlet. Pressure sensors measure the differential pressures at rotor / impeller and stator / guide vane system. The flow rate is measured by an electromagnetic flow meter. The measured values are read from digital displays.

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

Learning Objectives / Experiments

- recording characteristic curves
- determining dimensionless characteristics
- velocity triangles and pressure curves
- investigation of energy conversion within the turbomachine
- how blade / vane shape affects power and efficiency
- determining the outlet angular momentum and its effect on the power
- cavitation effects