NUMERICAL, EXPERIMENTAL AND ANALYTICAL INVESTIGATION FOR HIGHER WIND TURBINE EFFICIENCY

The study is based on Energy Possessed by the running rotors. Explained with Analytical Reasons and worked with Numerical Fluid Mechanics calculations for both useful energy produced and energy wasted by the running model rotors are also presented. The experimental work is carried out for nine Horizontal Axis wind rotors and one Vertical axis wind rotor physical models. By Changing the Wind Turbine Rotor Geometry and analyzing their theoretical and actual performance for a possible higher efficiency of energy extraction from the moving air. Between speed and power of the wind rotor an optimum size and angle are to be kept for each of the blades to harness the possible maximum kinetic energy from the wind is the deduction from the results as otherwise wastage of energy is higher. Energy is an imported input in many sectors of any country’s economy. Present Position: 1. Population of world has increased 2. Standard of living of human beings has also increased and so the per capita energy consumption has increased. A wind turbine is a rotating machine and looks like a big fan that converts the kinetic energy of wind into useful mechanical energy. This Mechanical kinetic energy can be used directly by any machinery such as a Water pump, Wood cutter or for grinding food grains. Such a machine is called a wind mill which is a very old device historically. If in a wind turbine the mechanical energy produced is instead converted into electricity then it is a wind generator, wind turbine, wind power unit (WPU), wind energy converter (WEC) and so on the names which also extracts energy from moving air by slowing down the speed of the wind, absorbing and transferring this harvested mechanical kinetic energy of the moving air into a rotating shaft which usually turns an alternator or generator to produce electricity. Wind turbines are by and large (a) Horizontal Axis (b) Vertical Axis Types. The Present experimental study the results are showing significant improvement for the horizontal axis type wind turbines which are more efficient than the vertical axis type of wind turbines. A conclusion is that an increasingly larger size of the blades from the inner to the outer periphery with appropriate angle of the blade is able to produce more energy output from the same moving air. With an increased efficiency one particular rotor is able to run and produce higher energy output. From a constant air flow source and by placing each of the model rotors in front of the blowing air the rotors are allowed to rotate and tested. The rotors are so designed and made to have various Solidity ratio, Blade angle, Tip Speed ratio and Mass. Different Energy possessed by each of them while running and efficiency of each of the ten rotors are calculated numerically and experimentally. The energy equation is used and the maximum rotational speed of the rotors under identical conditions are measured using noncontact type optical sensor. About 30 to 40 % more energy efficient is the case for particular rotor geometry is reported and recorded for the first time which can be due to better engineering design. Since the experimental test results also firmly supports the above final conclusion it is recommended that Commercial wind turbine manufacturers can confidently change the existing wind turbine rotor blade design from the smaller tip at the outer end of each blade into a larger tip. The increase in efficiency can be analytically justified to the higher torque produced and hence the more energy extraction by the larger tip area of the blades.