Design and Perfomance Comparison of a Horizontal Axis Wind Turbine and a Cross Flow Type Wind turbine

Abstract

A major concern these days is the adverse effect of human activities on the environment. Carbon emissions especially have been linked to global warming and climate change. In addition, the rising demand for energy has led many countries to look for new, renewable and environmentally friendly power sources for supply. One of these sources is the wind and this study looks two alternatives to harness the energy.

These two alternatives are wind turbines that are able to convert the kinetic energy available in the wind to useful mechanical energy which then can be used to generate electrical power. This study will investigate and compare the performance of the two types of wind turbines by using commercial CFD software. The following are several objectives of the investigation.

The first objective is to study and utilize the current theories in wind turbine technology to design a 10kW horizontal axis wind turbine blade. Once the blade is designed, the performance characteristics of the blade will be studied by using a commercial CFD code ANSYS CFX 13.0.

Once the investigation on the 10kW blade was completed, the next objective is to simulate a 10kW cross flow type wind turbine using ANSYS CFX 13.0. Also, several simulations were done to study the effect of a nozzle and diffuser on the performance of the cross flow wind turbine.

The final objective is to compare the performance characteristics of the 10kW horizontal type wind turbine to the 10kW cross flow type turbine with a nozzle and diffuser.

At the completion of this study, a horizontal axis wind turbine using 3 different airfoils was designed using various theories that were studied. This turbine was simulated using ANSYS CFX v13 and achieved an output power of 11.54kW at 10m/s and a power coefficient of 0.45 at the rated wind speed of 10m/s.

The cross flow turbine was numerically analyzed in the commercial code ANSYS CFX v13 with the nozzle and diffuser. It was found that the nozzle increased the velocity of the air entering the turbine and therefore increased the power output and power coefficient of the turbine. The diffuser did not have much effect on the performance characteristics. Furthermore, the best case turbine with a nozzle and diffuser attached produced about 2.8kW and a power coefficient of 0.11 at a wind speed of 10m/s.