臺灣博碩士論文加值系統

本研究中使用ANSYS FLUENT數值方式研究400cc踏板車的無級變速器（CVT）內的固體/液體的溫度。以Moving Reference Frame(MRF)方式模擬旋轉運動和平行運動，實現了氣體和固體之間的共軛熱傳效應。本研究的重點放在CVT幾何參數的配置，皮帶的熱傳導率、皮帶減速比和曲軸箱散熱量對CVT熱流場的影響上。
數值結果發現，CVT內分隔板的設計可以將流體引導到皮帶附近，防止高溫流體滯留在CVT內，進一步降低皮帶和皮帶輪的溫度。皮帶導熱率的增加會增加皮帶的平均溫度，但會降低其溫差。此外，由於轉速的增加，當皮帶從高減速比變化到低減速比時，被動皮帶輪的溫度將會降低。還研究了從曲軸箱到CVT殼體的散熱，使得與曲軸箱相鄰的殼體中的肋條用作翅片，以增強從發動機到CVT殼體的熱傳遞。與其他研究者提出的方法相比，該方法被認為是最詳細的模型。
關鍵字：CVT、CFD、連續變速器、散熱

In this study, the temperature of solid/fluid inside a continuously variable transmission (CVT) of a 400 cc scooter is investigated numerically utilizing ANSYS FLUENT. The moving reference frame(MRF)techniquewith conjugate heat transfer between gases and solid rotation/translationare implemented to carry out the simulation.The emphasis of the present study is put on the effects of CVT housing configuration, belt’s thermal conductivity,belt’s speed ratio and the heat dissipated from the crankcase on the thermal-flow-field of CVT.
The numericalresults show that it is foundthat the proposed design of partition plate inside the CVT housing can direct the flow to belt and prevent the heat fluidremainin the CVT, and can further decrease the temperatures of the belt and pulley.The increase of thermal conductivity of belt will increase the average temperature of belt but minimizethe temperature difference on it.

In addition, the temperature of driven pulley will decrease when belt transition from high ratio to low ratio due to the increase of itsrotational speed. The heat dissipation from the crankcase to CVT housing is also exploredthat the ribs in the housing adjacent to the crankcase served as the fin to enhance the heat transfer from engine to CVT housing.In comparison with the methods proposed by other researchers, thismethodis found to be the most detailed model.
Keyword: CVT、CFD、Continuously Variable Transmission、Heat Dissipation

摘要 I
ABSTRACT II
謝誌 IV
目錄 V
表目錄 VII
圖目錄 VIII
符號索引 X
希臘字母 XI
第1章 緒論 1
1.1 前言 1
1.2 文獻回顧 2
1.3 研究動機 11
1.4 研究內容 11
第2章 研究方法 12
2.1 基本假設 12
2.2 數學模式 12
2.2.1 連續方程式 (Continuity equation) 13
2.2.2 動量方程式 (Momentum equation) 13
2.2.3 能量方程式 (Energy equation) 14
第3章 電腦數值模擬 15
3.1 幾何模型 15
3.2 網格與材料 19
3.3 邊界條件 22
3.3.1 流體部分 22
3.3.2 熱傳部分 22
第4章 結果與討論 27
4.1 CVT幾何參數分析 29
4.2 CVT皮帶熱傳導係數參數分析 34
4.3 CVT皮帶減速比參數分析 36
4.4 加入CVT外殼固體熱傳後的CVT溫度探討 40
4.5 CVT簡易分析模型的散熱性能探討 43
第5章 結論 46
第6章 未來展望與建議 47
參考文獻 48
作者簡介 50

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