Flow Analysis of a Wind Power Plant
During the construction of a wind power plant there are a number of issues to be solved. The location of the plant is a key element for the configuration and provides the most important parameters for the design. The structural requirements in terms of foundation, tower and load distribution are different, e.g. in the onshore and offshore application. Additional, requirements imposed on the materials and the infeed ofgenerated ernergy need to be solved. The design of such a system emerge a number of challenges that must satisfy both mechanical and electrical as well as aerodynamic requirements. FEM analyzes provide insight in all respects.
Task
In this project, we have devoted ourselves to the investigation of one of the most important components of the system - the rotor. It harvests the energy of the wind and converts it into electrical energy. Therefore the rotor blade has to be designed for an optimal energy transfer. On the one hand it must provide drag and on the other the necessary flexibility.
Solution
For the approximation of the turbulent air flow we use the Reynolds-averaged Navier–Stokes equations. It is used in computational fluid dynamics to describe such scenarios. This makes it possible to perform experiments under different flow conditions.
Results
In analogy to a classical wind tunnel investigation we describe how various factors such as speed and pressure affect the blades. Figure 1 shows the velocity distribution of the turbulent wind flow on the rotor blade. We can observe that the air velocity is higher above and under the contact zone. In Figure 2 the pressure distribution is illustrated. The zone of the highest pressure is where the wind makes its first contact with the blade. Both figures show that the reduction of speed behind the rotor blade is associated with a decrease of pressure. In the analysis of the rotor blade different pressure zones could be identified. The highest pressure is investigated where the wind is impinging on the leading edge of the rotor. Behind the rotor a low pressure zone is created. Beside the aforementioned results it is possible to simulate the influence of temperature and pressure to the blade and the deformation produced by the air pressure on the contact surface with this model. That way effects of wind currents on the rotor are understandable and comprehensively representable.
Advantages of FEM-Simulation
- Time and cost savings compared to experimental tests
- Testing of various parameters and properties with little effort
- Repetition of the simulation with any number of scenarios