Bionic Design And Experimental Research Of Small Horizontal Axis Wind Turbine Blade Based On Biological Airfoil

As an inexhaustible and renewable green energy, wind energy has beenattracting wide attention by countries with worldwide energy shortage andenvironmental crisis. Currently, efficiency of wind turbine is about35%and there isstill a large room to improve to reach the theoretical efficiency of59.3%which isdemonstrated by Bates theory. Blades are the key components of the wind turbinesand the aerodynamic performance of blades can affect their efficiency which is mainequipment of wind power directly. Wind turbine blades are Consists of a series ofairfoil according to the specific sequence arrangement and the blade airfoilaerodynamic performance including their arrangement has important effects on theperformance of blades。This paper selects swallow airfoil at the aspect ratio of25%, swallow airfoil atthe aspect ratio of35%, Long-eared owl airfoil at the aspect ratio of50%and seagullairfoil at the aspect ratio of50%to comparative analysis with the standard airfoil Inthe100W small horizontal axis wind turbine operating conditions and using S-Amodel to analyze the aerodynamic characteristics of the bionic airfoil and standardairfoil at different angles of attack. The results show that in the range of0～20°ofangle of attack, bionic airfoils have improved greatly in terms of lift coefficient andlift-drag ratio than the standard airfoil. The stall angle of bionic airfoil increased dueto its excellent aerodynamic characteristics.Based on the above findings, the paper reconstructs the standard wind turbineblades of100W and six groups of blades which combined with bionic airfoils. Theyare25%swallow airfoil improved blades,35%swallow airfoil improved blades,50%Long-eared owl airfoil improved blades,50%seagull airfoil improved blades,50%Long-eared owl airfoil designed blades,50%seagull airfoil designed blades.Contrast analysis was carried out on the bionic blade and standard, strengthcharacteristics simulation analysis show that the bionic blade maximum equivalentstress is less than standard blade, strength performance confirms meet the designrequirements. Aerodynamic characteristics of numerical simulation using the SST model, analysis shows that the surface pressure of bionic blade, distance of0.4m,0.5m airfoil surface pressure to the hub are greater than the standard blade. It isconfirmed that the25%swallow airfoil improved blades,35%swallow airfoilimproved blades,50%seagull airfoil improved blades improving degree is larger.In order to obtain the real-time operation condition of wind turbine blades,accurate testing the output power of bionic blade and standard blade, this paperstructures the efficiency of indoor wind turbine test-bed. Experiment showed that thebionic airfoil design blade solidity was lower than those of standard blade, There isno efficiency improvement of50%Long-eared owl airfoil designed blade within theentire test wind speed; the efficiency of50%seagull airfoil designed blades is higherthan standard wind turbine blades on average increased by9.5%, the biggest increaseby13.58%when v>7m/s; Bionic airfoil improvement blade is the same as thesolidity of standard blade, the output power of50%Long-eared owl airfoil improvedblades increase slightly under low wind speed, on average increased by5.92%, thebiggest increase by8.66%when v <6.4m/s; the efficiency of25%swallow airfoilimproved blades,35%swallow airfoil improved blades and50%seagull airfoildesigned blades are generally increased by25.00%,26.48%and25.00%In the entiretest wind speed.