بررسي تجربي و عددي عملكرد آيروديناميكي ايرفويل تردميلي به همراه آشكارسازي ميدان جريان در تونل باد

چكيده انگليسي :

043 Experimental and Numerical Investigation of AerodynamicPerformance of Treadmill Airfoil with Flow Visualisation Wind Tunnel Seyed Ali Kazemi ali kazemi1@me iut ac ir Date of Submission 2015 08 03 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisors Mahdi Nili Ahmadabadi m nili@cc iut ac ir Mohsen Saghafian saghafian@cc iut ac irAbstractThe ratio of lift coefficient to drag coefficient in airfoils is within the effective parameters in airfoilaerodynamic performance and also in manufactured machines based upon an airfoil like wind turbine Inthe present study the new aerodynamic geometry has been defined based on the theory of objects withmoving surfaces which is also applicable in the design of blade section in Magnus wind turbines Theintroduced geometry is based on Treadmill geometry but its initial circle diameter is greater than that of theend and it is called as Treadmill airfoil In this work these two similar geometries with differentdimensions were placed against to the free stream with low speed Then by inducing a tangential velocityon the surface its effect on lift coefficient and drag coefficient was investigated using ANSYS CFXsoftware The effect of tangential velocity on the surface was studied in different velocities and angles ofattack to compare with a stationary surface mode The results show that the lift and drag coefficients andtheir ratio are greatly changed by surface tangential velocity According to the surface tangential motion the maximum ratio of lift to drag coefficient for the geometries number 1 and 2 are related to the angle ofattack of 0 and 5 degree with value of 130 and 56 respectively Moreover the maximum ratio of lift todrag coefficient for geometry number 1 in angles of attack 5 10 and15 are 81 90 and 57 respectively Inaddition the maximum ratio of lift to drag coefficient for geometry number 2 in angles of attack 0 10 and15 degree are 52 49 and 45 respectively It should be noted that the numerical method was applied tothe geometry 1 by a tangential motion of a section of the surface which its result showed that besides anincrease in lift coefficient the drag coefficient quantity will be negative In result a great ratio of liftcoefficient to drag coefficient is achieved It is worth mentioning that the consumption power required togenerate the tangential movement along the surface has a very low value In the other step the laboratorymodel of Treadmill geometry and experimental setup were designed and manufactured Then the modelwas positioned in the wind tunnel and qualitative and quantitative effect of tangential velocity on flowaround geometry was investigated In the qualitative study the positions of the sepration and stagnationpoints were specified which these results are also so well and well matching the numerical solution In thequantitative study the lift and drag coefficients of tredmill airfoil were measured dimensionless tangentialvelocity up to 1 and the attack angles in 0 5 and 10 degrees using loadcell and side force method As aresult the surface tangential velocity leads to increase in lift coefficient and lift to drag ratio Finally thedifference between the values of numerical solution and experimental investigation are acceptable whichrepresents the validity of numerical solution Keywords Magnus Effect Wind Turbine Moving Surface Airfoil Wind Tunnel

كاظمي، علي

بررسي تجربي و عددي عملكرد آيروديناميكي ايرفويل تردميلي به همراه آشكارسازي ميدان جريان در تونل باد

اثر مگنوس , سطوح متحرك , توربين باد