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The Flow Control Of Airfoil Separation Based On Deflecting Wing

Posted on:2020-06-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y Z WangFull Text:PDF
GTID:2370330590493694Subject:Engineering
Abstract/Summary:PDF Full Text Request
Airfoil separation flow control is the most popular research field in current fluid mechanics.It has great theoretical and economic value for aircraft high angle of attack flight,short takeoff and landing,and flight safety,an innovative technique for flow control,Deflecting Wing,is investigated by Numerical simulation in the present thesis.The basic idea of the Deflecting Wing that is deflecting the coming flow to airfoil.High lift airfoil is chosen as the baseline.The paper first selects 30P30 N as the Deflecting Wing and studies its flow characteristics.The results show that the Deflecting Wing is able to deflect flow at least 15°,which has verified the basic idea.Second,the paper combines numerical simulation calculation with orthogonal design to optimize the multi-parameters of the Deflecting Wing with the goal of delaying the stall angle of attack and increasing the lift.The results show that the optimal parameter state of Deflecting Wing delays the stall angle of the control airfoil by 5° and the maximum lift coefficient by 10%.And the parameter that has the largest influence on the unit level is the angel of the Deflecting Wing.Furthermore,the angle of Deflecting Wing is further changed to study the influence characteristics.The results show that the flow deflection wing can restrain flow separation and enhance lift of the airfoil in a range of angles.Within this range,as the angle increases,the separation is delayed,and the lift first increases.Less,the resistance has been reduced.Again,analysis of mechanism was done on the new flow control method by numerical simulations.Deep research of flow direction changing,boundary layer and surface friction characteristics are carried out to investigate the mechanism of Deflecting Wing.The results indicate that the Deflecting Wing increase the angel of flow around the leading edge of the wing and decrease the angel of the coming flow to make it deflect to the upside of the wing.Other than this,the Deflecting Wing can easily change the velocity profile in the boundary layer and make it more “fuller”.It decrease the shape factor and increase the stability of the boundary layer to restrain the flow separation.In order to investigate the applicability of the Deflecting Wing for different airfoils,a common airfoil NACA0012 and a special wind turbine airfoil NREL S809 are chosen for numerical simulation.Both the results show that Deflecting Wing delays the stall angle of the NACA0012 airfoil by 4° and the maximum lift coefficient by 40%,and the S809 airfoil by 4° and the maximum lift coefficient by 20%.Providing reference data and theoretical support for engineering applications of Deflecting Wing control technology.
Keywords/Search Tags:Flow control, Deflecting Wing, Flow separation, Flow control mechanism, Multi-element airfoil, Numerical simulation
PDF Full Text Request
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