THE INFLUENCE OF SOME GEOMETRICAL PARAMETERS ON THE ENERGY INDICATORS OF THE VERTICAL AXIS WIND TURBINES

• Date: 2017
• Main Authors: Knysh, L., Goman, O.
• Format: Article
• Language: Russian
• Published: Institute of Renewable Energy National Academy of Sciences of Ukraine 2017
• Subjects: vertical axis wind turbine; double-disk momentum theory; drag coefficients of the blade profile; computer simulations; blade installation angle
• Online Access: https://ve.org.ua/index.php/journal/article/view/22
• Journal Title: Vidnovluvana energetika

The vertical axis wind turbines have a number of advantages over horizontal axis wind turbines. Vertical axis wind turbines proved to be especially useful in the autonomous power systems in locations where wind direction changes often. During the design of the vertical axis wind turbines it is common to use the propeller wind turbines analysis approaches, for example, the double-disk momentum theory. In this paper an improved engineering analysis procedure for determining the dependence between power coefficient, momentum coefficient and speed number (dimensionless flow velocity) is presented. For the analysis refined values of the drag coefficients for selected profile were used. These values were determined based on full-scale experiments in the wind tunnel T-5. The mathematical model was created based on the force balances. On the one hand these forces are expressed using drag coefficient of the profile, on the other hand they are calculated based on the momentum theorem. In the integral functions   geometric and dynamic characteristics of wind engine are taken into account. The numerical analysis algorithm was compiled based on the received data and used expressions for averaged torques. The parametric studies for selection of some geometric and dynamic characteristics of the system were conducted. It was determined that decrease in the chord profile length has positive influence on the power coefficient value and provides stable work of the wind turbine in the wide range of the wind velocities. The change of the blade installation angle can have a negative influence on the general efficiency of the system.