臺灣博碩士論文加值系統

本研究以數值計算模擬含機身與旋翼組之雙旋翼飛行器，探討其於前進飛行時不同操作條件下之氣動力特性。上、下兩組旋翼均由三葉片組成，其葉片翼切形有NACA0012對稱翼與Viper-X非對稱翼兩種類型；後者另考慮旋翼葉片尖端具有20、35及40度三種後掠角。數值方法採用ANSYS/Fluent商用軟體旋轉參考座標模擬混和計算域，結合結構與非結構性組合網格系統。流動之統御方程為雷諾平均Navier-Stokes方程組，並以SST k-ω模型模擬紊流特性。研究之初，先比較各種不同條件下之下洗速度，進而探討懸停與前進飛行等不同條件下，所產生的升力、扭矩與前進推力等結果，並比較具對稱與非對稱翼切形旋翼之結果以及分析旋翼葉片翼尖後掠對氣動力之影響。結果顯示:綜合而論，前飛各種操作條件下，具有非對稱Viper-X翼切形且葉片翼尖後掠35度之旋翼組有較佳之氣動力性能。

In this study, coaxial rotor vehicles with rotor-fuselage combination are simulated numerically to study the aerodynamic characteristics under various operating conditions during the forward flight. The upper and lower rotor each consists of three blades. Two kinds of rotor blade, NACA 0012 (symmetrical wing) and Viper-X (asymmetric wing), are considered. For the latter, in addition, the rotor blade tips with sweepback angles of 20, 35 and 40 deg are taken into accout. The numercial simulations are performed using the commercial package ANSYS/Fluent with mixed model of rotating frame of reference, and combination of structural and nonstructural grid system. The fluid flow is governed by Reynolds-averaged Navier-Stokes equations and the turbulence characteristics are simulated by the SST k-ω model. At the beginning of the study, the downwash speeds at various conditions are compared first, and then the results of lift, torque and forward thrust at conditions of hovering and forward flight, and symmetrical and asymmetric rotors are explored. The influence of the blade tip sweepback on the aerodynamic force is also analyzed. From the results under various operating conditions, it can be summarized that the coaxial rotor of Viper-X blade with tip sweep of 35 deg shows relatively better aerodynamic performance.

誌謝i
摘要ii
ABSTRACTiii
目錄v
表目錄vii
圖目錄ix
符號說明xviii
第一章 緒論1
1.1 前言1
1.2 文獻回顧3
1.3 研究動機與研究目的5
第二章 物理模型與統御方程組6
2.1 物理模型6
2.2 統御方程組7
2.3 SST k-ω紊流計算模型8
第三章 數值計算方法22
3.1 數值模擬程序22
3.2 離散方法23
3.3 網格配置與邊界條件24
3.4 收斂準則與鬆弛因子26
第四章 結果與討論36
4.1 下洗速度比較36
4.2 不同翼型懸停結果之比較39
4.3 不同條件下前進飛行結果之比較41
4.3.1 Viper-X非對稱翼翼尖後掠35°型不同條件下前進飛行結果之比較41
4.3.2 Viper-X非對稱翼型相同條件下前進飛行結果之比較44
第五章 總結76
參考文獻79
附錄81

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