本文利用數值方法模擬二維NACA-0012機翼積冰後之外形並求出其機翼剖面升力係數，來探討積冰後之外形對空氣動力性能之影響。積冰模擬之數值分析分為四個部分：第一為流場的計算，求解出紊流之Reynolds Averaged Navier-Stokes方程組，得到NACA-0012於低速飛行時之流場現象。第二為水滴軌跡的計算，將水滴軌跡運動方程式帶入流場解即可獲得水滴之運動軌跡，並判斷水滴是否會撞擊到翼表面，進而計算出撞擊在翼面上局部之水滴量，亦即聚集效率。第三為利用質量、能量守恆來計算水滴結冰過程局部之積冰量，並模擬出積冰外形。第四為利用流片法計算出機翼積冰後之翼剖面壓力係數，並積分求得升力係數。
本文研究目的在探討在兩種不同的大氣條件下造成不同的積冰型態。形成霜狀冰與清透冰之參數包含大氣溫度、自由流速度、雲層之水含量、水滴大小等，其中影響最大的是大氣溫度。當大氣溫度越接近水的凝固點時，越容易形成清透冰似角狀之特徵外形。此類積冰結構大大的改變原有機翼前緣之幾何形狀，造成升力係數下降。若大氣溫度越低於水的凝固點時，則形成較具規則形狀之霜狀冰外形，但升力係數的減少不如清透冰來的大。

In this study, a numerical method is developed to simulate the two–dimonsional shape of airfoil after icing, and to compute the airfoil aerodynamic lift coefficient degrading due to icing. The numerical analysis of ice accretion simulation is divided into four parts：(1) The calculation of low-speed flowfield by using turbulent Reynolds Averaged Navier-Stokes equations solver to obtain the phenomenon of flowfield over NACA-0012 section. (2) The results of the water droplet trajectories by the equation of motion in the flowfield as obtained in part 1 determine the droplets impingement on the airfoil, and then to evaluate the amount of water that accretes on the airfoil, i.e., the collection efficiency. (3) Employing the mass and energy conservation laws to calculate the local quantity of ice accretion during the process of freezing, and to simulate the shape of the ice. (4) Using the panel method to evaluate the airfoil pressure coefficient and the lift coefficient after icing.
The objective of this study is to investigate the different types of ice accretion under two different atmospheric conditions, which cause the rime ice and the glaze ice on the airfoil. There are several parameters in the ice accretion, such as the air temperature, freestream velocity, liquid water content and the droplet size, etc. However, the main parameter is the air temperature. The glaze ice is characterized by the horned shape when the air temperature is around the freezing point. Formation of the glaze ice changes the shape of leading edge of airfoil greatly, and degrades the lift coefficient and changes the airfoil aerodynamic performance. As for the rime ice case, it forms some regular shape at lower air temperature under freezing point, and degradation of lift coefficient is not worse than the glaze ice is

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