"Research Paper(December, 2014)Evolving Windmill Blade Design forenhancing the performanceMittali Solanki, Radhika Gadara, Shivang Parmar and Sudarshan GuptaPGP’14 - School of Petroleum Management, PDPU, GandhinagarAbstract:This research is an attempt to explore the various facets and factors that affect thestructural design of windmill blades which in turn affect the output performance ofwindmill. The research primarily features three broad factors that lead to thedesign of the windmill blade profile – Aerodynamic Analysis, Structural Analysisand Geographical Analysis. Different parameters such as number of blades, lengthof blade, weight, wind speed, angle of attack etc. are also studied for evolving theblade design. How performance can be optimized with these changing factors,remains the main objective of this research.Introduction:Wind has been widely used as a source of energy for thousands of years, but wasreplaced by fossil fuels. Now that the fossil fuels are on the brink of depletion, needof renewable sources has emerged again. Apart from Solar energy, wind energy hasbeen identified as potential substitutes to the fossil fuels.Wind energy is produced through windmills – a structure consisting of majorly 3components, i.e. rotor component, generator component, structural supportcomponent. (Omar Badran). The rotor component includes the blades forconverting wind energy to an intermediate low speed rotational energy. Thegenerator component comprises of the electrical generator, the control electronicsand a gearbox component for converting the low speed rotational energy toelectricity. Lastly, the structural support component includes the tower foroptimally situating the rotor component to the wind energy source. (Fingersh L.,2006)There are primarily 2 orientations of a wind turbine which are classified on thebasis of their axis on which the turbine rotates – VAWT (Vertical Axis WindTurbine) & HAWT (Horizontal Axis Wind Turbine).- A turbine with a shaft mounted horizontally parallel to the ground is calledHAWT. (Peter J. Schubel, 2012)- A turbine with a shaft mounted perpendicular to the ground is called VAWT.(Peter J. Schubel, 2012)Some distinguished characteristics of the two rotor configurations:- VAWT has low tip speed ratio & the rotor speed cannot be controlledeffectively.- VAWT can avoid heavy tower loads by mounting the generators on theground.- HAWT has proved its dominance over VAWT through its attributes ofcontrolled rotor speed.- One major advantage that VAWT possesses over HAWT is that the bladeshave a constant shape as well as no twist in the curvature is required. Thisin turn reduces the cost of manufacturing. But HAWT is commercially moreviable than VAWT. This is due to low rotor speed achievement in VAWTwhich results in poor output performance.- HAWT generally faces the upwind while VAWT is not affected by the directionof wind.- VAWT is generally easier and cheaper to maintain due to its proximity to theground. - HAWT need to be large so as to generate required power unlike VAWT.Turbines cannot function at very high speeds as they are prone to take damage.Thus an automatic controller is installed that turns on the turbine when wind isblowing at prime speed and shuts off when wind becomes stronger. Historic and Modern Rotor Designs (Peter J. Schubel, 2012) "