Power and Ventilation Performance Study in a Modified Vertical Axis Wind Turbine Based on Semi-Analytical Approach

In the current research, a novel vertical axis wind turbine producing both power and ventilation is presented. The idea is similar to the ancient wind catchers. The wind capacity of the Manjil city in Iran has been studied and a typical home-scale wind turbine has been assessed. To assess and modify the geometry, a ۳D semi-analytical code has been developed based on double multiple stream tube, DMST, theory. The validation analysis has been accomplished by the reference turbine. Using this code, the turbine performance including power coefficient and flow diversion index has been studied. Particularly the effect of blade cone angle on the power deficiency and ventilation ratio has been investigated. The results of the parameter study would reveal that for the optimal range of tip speed ratio, ۲.۹-۳.۲ based on the power curve, it is feasible to produce up to ۴۰۰ m۳/h ventilation flow. it would be obtained by ۲۰-degree blade inclination and is equivalent to ۲.۵% of the total flow entering the rotor. The power deficiency due to this change is ۳۰% which is compromised by the ventilation capability. It is also depicted in the results that, power attenuation could be minimum when the suitable TSR and the appropriate geometry are selected. The proposed layout, could produce ۵۰ to ۲۰۰-watt shaft power in terms of the flow diversion level. Finally, some generalized trends of the objective functions have been drawn. The methodology seems to be versatile for the ongoing problems in the field of vertical axis turbine optimization.

Keywords:

wind energy potential , Modified VAWT , DMST method , power coefficient , Ventilation coefficient , Design optimization