Turbine performance simulations are performed by CFD, Computational Fluid Dynamics, has recently been developed to be able to do stationary as well as transient simulations. It is a powerful tool for optimizing turbine design. Transient simulations can also predict pressure fluctuations caused by stator rotor interaction (synchronous) and draft tube oscillation.

These simulations are in its ultimate use, simulation of the whole turbine. However, the time use of such simulations are tremendous because 3D representation of the whole turbine makes it necessary to solve billions of equation simultaneously. Short cuts and simplifications are therefore necessary to make it useful as an engineering tool. Verifications in the laboratory shows, however, a good coherence.

Pressure fluctuations caused by the turbine behaviour will travel and reflect in the conduit system, which will again affect the turbine behaviour. The turbine and the conduit system’s dynamic behaviour will mutually influence each other. Hence, two identical turbines will behave differently in different conduit systems.

To fully explain the mutual behaviour, the turbine as well as the conduit system must be modelled and solved simultaneously.

For transient simulations of the conduit system, the general experience is that 1D models are sufficient. This has been reported by numerous scientific papers, where simulation have been verified by field measurements.

So the core ambition of this project is to make a numeric representation of a power plant combining 3D simulations of the turbine and 1D simulations of the conduit system.

To establish such a model will be the first step, modelling the turbine and conduit system in the Waterpower Laboratory and verify the simulations by laboratory measurements.