Numerical simulation of the flow field characteristics of various winglet shapes

機構典藏 > College of Engineering > Graduate Institute & Department of Aerospace Engineering > Thesis > Item 987654321/35626

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Title:	Numerical simulation of the flow field characteristics of various winglet shapes
Other Titles:	在不同翼尖小翼下的流場特性之數值模擬
Authors:	周鴻旭;Chou, Hung-hsu
Contributors:	淡江大學航空太空工程學系碩士班宛同;Wan, Tung
Keywords:	翼尖渦流;翼端渦流;誘導阻力;螺旋狀翼端小翼;Trailing Vortices;Tip Vortices;Induced Drag;Spiroid Winglet
Date:	2005
Issue Date:	2010-01-11 06:53:09 (UTC+8)
Abstract:	減少飛機飛行時的阻力是飛機製造商的一個主要的目標，飛機在巡航時，摩擦阻力和升力誘導的阻力是造成阻力的兩個重要的關鍵。在翼尖形成的渦流是當升力存在時，所造成的一個不可避免的產物，產生翼尖渦流需要能量，而機翼和空氣之間能量轉換就是由誘導阻力轉移而來，另外，由大型飛機產生的強大翼尖渦流會增加它後方小型飛機的危險性，例如波音747客機所產生的翼尖渦流有能力使太靠近它的輕型飛機失去控制，某些意外就因為這樣而發生，這也是飛機在起飛和降落時需要間隔很大的空間的原因。翼尖渦流可以由移動或是減低的方法來做修正，這些修正方法可以用翼尖的裝置如翼尖小翼來達到。在這篇論文中，以計算模擬的方式，利用FLUENT軟體當作求解器，討論當不同翼尖小翼外型時，在翼尖附近的流場情形，目標是了解各種翼尖小翼對渦流結構所造成的變化。吾人選擇用ATR-72的機翼當作基準，附加上各種不同外型的翼尖小翼，在馬赫數等於0.2與0.41時，從0度到16度之間各種不同的攻角的情形下，比較其升力、阻力的變化，而其中包含了一種新的翼尖小翼外型，叫做螺旋狀翼尖小翼，吾人也設計出一些不同外型的螺旋狀翼尖小翼，其中包括不同的cant angle、不同的螺旋半徑和不同的翼尖小翼的機翼剖面，試著找出一種能減少最多阻力的最佳外型，進而達到省油的目的。 Drag reduction is one of the main objectives of the transport aircraft manufacturers. The drag breakdown of a transport aircraft at cruise shows that the skin frictional drag and the lift-induced drag constitute the two main sources of drag. The vortices produced in the wing tip are unavoidable products by the presence of lift. Generation of tip vortices requires energy, and transfer of this energy from wing to air is induced drag. Large induced drag will reduce airplane endurance while cruising, and also increase the fuel consumption. Furthermore, wing tip vortices on large aircraft can be so powerful as to endanger smaller aircraft flying behind them. For large airplanes such as Boeing 747, these tip vortices can be powerful enough to cause small airplanes following too closely to be out of control. The energy of the vortices can be modified through displacement and reduction. These modifications can potentially be achieved by the use of wing tip devices such as winglets. In this paper, use computational method, and regard FLUENT software as flow solver. Investigating wings with different shapes of winglet, the situation of the flow field near the wing tip. The objective of this work is to gain a greater understanding of how the wing tip device modifies the vortex structure. Use ATR-72 wing as the datum, and add different types of winglet shape, at Mach number equal to 0.2 and 0.41, with different angles of attack, to compare the differences in CL and CD. It is including a new winglet appearance－spiroid winglet. I also design different kinds of spiroid winglet, including spiroid winglets with different cant angles, different sprial radius, and different spiroid winglet airfoil section, hope to find a optimize shape which can reduce the drag most, and then achieve the aerodynamic performance and fuel-efficient goals.
Appears in Collections:	[Graduate Institute & Department of Aerospace Engineering] Thesis

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