臺灣博碩士論文加值系統

本論文研究的主題為利用數值方法模擬馬達溫升，首先對馬達個別元件進行模擬，所探討的馬達元件有三部分，即外扇、風罩及散熱翅。再將此三個元件組合，以組合的模型，模擬馬達於標準狀況(standard condition)下運轉的情形。
本研究的原因，是因為馬達的流量及溫升通常藉由實驗直接量測實體而得，當更改元件尺寸時，又需重新開模及鑄造，耗費時間成本。若能利用數值方法調整元件尺寸，即可計算出所需的流量及溫升，節
省時間和成本。
本論文中所使用之分析軟體為STAR-CD。此軟體求解所使用的數值方法為有限體積法(F.V.M)，其流場中流體性質之計算點為網格的中心點，以此進行每個格點之疊代計算，直到所有格點皆達到收斂為止。
個別元件分析部分，外扇是在移除風罩的狀況下，給定一進風口段及出風口段的長度，測試項目包括(1)給定壓力差計算流量；(2)給定流量計算壓力差。此部份吾人選取兩把外扇進行分析。風罩是在探討不同開孔率與局部阻力係數之間的關係，並使用孔係材料取代風罩。散熱翅是進行其冷流場分析，計算在流體通過散熱翅溝槽時所產生的速度降。吾人對兩組散熱翅模型進行分析，以比較不同尺寸但幾何外形相似的兩組散熱翅，何者的散熱性能較佳。最後將外扇、用孔隙材料取代的風罩以及散熱翅三部份加以組合，在給定的轉速及邊界條件下計算流量及散熱翅速度降。
計算結果顯示，外扇在不同的邊界條件下所計算出的流量或壓力差，與實驗值相比，其誤差均能保持在一容許的範圍之內；孔隙材料可以藉由給定適當的多孔值係數，很準確地產生一個吾人所需要的壓力降，因此吾人可以將之用來取代實際的風罩；長度較長的散熱翅以及翅高較短的散熱翅具有較佳的性能。組合的模型所模擬的流量其誤差亦在一容許的範圍內。

The title of this thesis is simulate temperature rise for electrical motor
by numerical methods.First we simulate component of electrical moter separately,containing outer fan,cover and fin.Then we combine three components simulating electrical motor working under standard condition.
The reason of this research is saving time and money.Flow rate and temperature rise for electrical motor usually defined by measuring motor directly.When changing motors dimensions,it needs to open mold and manufacture again,wasting time and money.We can save time and money by changing component''s dimension and computing flow rate and temperature rise using numerical methods.
In this thesis we use STAR-CD to analyze motor.The numerical methods of this software is finite volume method(F.V.M),
computing points of fluid in flow field are at centers of cell,every cell performing computation repeatedly until all cells arrive convergence criteria.
Individually analyzing,for outer fan we remove cover and giving an inlet region and outlet region to test two items:(1)Giving pressure difference to compute flow rate;(2)Giving flow rate to compute pressure difference. In this section we select two type of outer fan to perform analysis.We discuss relations between different porosity area ratio and local drag coeffic-
ient(pressure drop coefficient),and using porous media replace baffle plate.We analyzing cold flow field of fin,computing velocity drop of fluid passing gap of fin.We select two type of fin to perform analysis,comparing them with different dimensions but similar geometries,whom have better performance.At last,we combine outer fan,cover replace with porous media and fin,computing flow rate and pressure drop across fin under given rotating velocity and boundary conditions.
Results shows that,computation of outer fan at different boundary conditions to get flow rate or pressure difference,whose error can decrease in a tolerance range;porous media can create a pressure drop which we want
by giving proper porous coefficients,so we can replace actual cover by porous media;fin has better performance which has longer length and shorter fin height.When using combined model’s simulating mass flow,which error also in a tolerance range.

1 導論
1.1 前言--------------------------------------------------12
1.2 計算流體力學程式的計算步驟----------------------------14
1.3 研究動機----------------------------------------------18
2 數值模式的建立
2.1 流體力學統御方程式------------------------------------19
2.2 紊流模式----------------------------------------------21
2.3 STAR-CD中的數值運算-----------------------------------23
2.4 馬達各部位元件說明------------------------------------26
3 外扇
3.1 問題描述----------------------------------------------28
3.2 網格建構----------------------------------------------29
3.3 邊界條件設定------------------------------------------35
3.4 計算結果----------------------------------------------39
3.5 綜合比較----------------------------------------------42
3.6 速度與壓力分布探討------------------------------------45
4 風罩
4.1 問題描述----------------------------------------------58
4.2 網格建構----------------------------------------------64
4.3 邊界條件設定------------------------------------------65
4.4 計算結果----------------------------------------------65
4.5 綜合比較----------------------------------------------78
4.6 速度與壓力分布探討------------------------------------84
5 散熱翅之冷流場分析
5.1 問題描述----------------------------------------------91
5.2 網格建構----------------------------------------------93
5.3 邊界條件設定------------------------------------------94
5.4 計算結果----------------------------------------------96
5.5 速度與壓力分布探討------------------------------------100
6 外扇與風罩及散熱翅的整合
6.1 問題描述----------------------------------------------107
6.2 網格建構----------------------------------------------107
6.3 邊界條件設定------------------------------------------109
6.4 計算結果----------------------------------------------111
6.5 速度與壓力分布探討------------------------------------118
7 結論
7.1 外扇結論----------------------------------------------127
7.2 風罩結論----------------------------------------------127
7.3 散熱翅結論--------------------------------------------128
7.4 整體結論----------------------------------------------128

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