Experimental and Numerical Studies on a Cross Axis Wind Turbine

Abstract

The drawbacks faced in HAWT and VAWT is overcome by cross axis wind turbine (CAWT) which exploits wind energy irrespective of wind direction. Experimental and numerical investigations are performed to study the performance parameters of CAWT and understand the flow physics. Experimental investigations are done by varying the wind velocity from 4m/s to 10m/s using mechanical loading. In general, coefficient of power ($\mathrm{C}_{\mathrm{p}}$) value of CAWT gradually increases and it reaches the maximum value around tip speed ratio 1.20. A peak $\mathrm{C}_{\mathrm{p}}$ value of 0.02385 is obtained for wind velocity V=10m/s. Numerical investigations using ANSYS CFX revealed the formation of vortex in CAWT. The size of vortex observed gets reduced as the wind velocity is increased resulting into improved performance for CAWT. On comparing the $\mathrm{C}_{\mathrm{p}}$ value of CAWT with existing VAWTs, it is observed that it is higher. The peak $\mathrm{C}_{\mathrm{p}}$ value is 177% more compared to existing VAWTs. Based on this study, it can be concluded that CAWT design enables it to give an enhanced performance by extracting wind energy from both horizontal and vertical wind components.