FFor turbine design, the CFD model was prepared and designed. For that end, all hydrodynamic and mechanical calculations have been performed, preparing a simulation model, analysing rotor requirements and carrying out geometric optimization. Different rotors' geometries have been designed for analysing efficiencies of different pilot plant designs.
As a result of simulation, maps of pressure and velocity were obtained as well as efficiency of the designed rotor. Also, thanks to the static study, the efforts and deformations of the rotor could be studied. With this studies, we also obtained the hydraulic losses in the pipe line.
Based on previous hydraulic and mechanical calculations and axial turbine designed, a turbine prototype at scale 1:5 has been built, in order to take tests and evaluate several performance features. Results obtained from this prototype will be extrapolated to prototype at scale 1:1.
Manufacturing a prototype at scale 1:1 was planned, however, during project progress, it was decided to perform a prototype at scale 1:5 previously. This decision does not modify project development and budget and its implementation is based in improving the design, costs saving and the possibility to study failures easily.
The validation at scale model 1:5 was performed in order to correct any mistake that may have committed during the conception of the machine design or drawing elaboration and not reproduce it in the prototype 1:1, since this would represent a great cost and huge waste of time. (see figure 3: Model 1:5 Hydro Low Head turbine).
Functional behaviour of the turbines built are being validated in laboratories from the University of Seville, obtaining the yield curves characteristic of the turbine (flow variation, behaviour under pressure variations, water speed, etc.) and analysing its vibrations as well as material resistance of the turbine and the piping system.
On the other hand, in order to develop the power stage system for operating turbine in variable speed mode, we have defined and designed, in a first approach, a system at smaller scale, in order to check that calculations were correct and control system was stable. This software was designed to be scalable in future real turbines. Software design was divided in four steps: software technical specifications, functional rules definition, final components selection and user interface creation.
Once the electronic stage system was totally defined and designed, a prototype of the electrical cabinet that manages the HydroLowHead regenerative turbine was built.
Functional behavior of the power cabinets was subsequently validated, obtaining the following results:
- The regenerative equipment is working within expected performance and efficiency;
- The base of the closed control loop works properly, although it needs to be improved, as well as adapted for real hydraulic conditions;
- The carried out design base are correct;
