論文摘要內容：
本文以計算流體力學(CFD)方法探討三維二行程引擎之掃氣效率。二行程引擎的性能關鍵是在於掃氣過程的優劣，掃氣的優劣指標為掃氣效率下與捕氣效率。在掃氣過程中活塞的形狀，掃氣口的位置、方向及角度，掃氣口流道角度，將影響引擎的掃氣效率。文中探討CO2由掃氣口進入汽缸內所行經的路徑(短路、廻環掃氣、中心損失、壁面迴路)對掃氣效率及捕氣效率的影響。本研究針對活塞頂面的幾何形狀，掃氣口及掃氣口流道的角度進行分析，結果顯示改變掃氣口流道角度(50°)能提升4%的掃氣效率及捕氣效率。針對改變掃氣口流道(50°)做分析，將排氣行程角度減少9°，能使掃氣效率及捕氣效率均提升13%。經研究結果發現原始引擎性能的關鍵在於排氣角度設計過大。

The Contents of Abstract in this Thesis:
In this paper, Computational Fluid Dynamics (CFD) method was used to study the scavenging efficiency by a 3D two-stroke engine. The scavenge process of a two-stroke engine is one of main factor to evaluate the engine performance. The geometry of piston surface, and the angle of transfer port and channel will affect the scavenging efficiency. CO2 flows in to the cylinder from channel are decided by the following four flow paths short-circuiting, loop scavenging, central loss and near-wall flow for scavenging efficiency (SE) and trapping efficiency (TE). In the study, three kinds of geometrics of piston surface, and three different degrees of transfer port and channels. In the results, the 50° channel of transfer port can enhance 4% SE and TE. And to reduced 9° of exhaust process in this case, the SE and TE will enhance 13%. Actually, the exhaust process of the origin engine in too long.

目錄
摘要 I
謝誌 III
目錄 IV
圖目錄 VI
符號索引 X
希臘字母 XII
第1章 前言 1
1.1 研究動機 1
1.2 文獻回顧 2
1.3 基本介紹 4
1.3.1 掃氣型式 4
1.3.2 流體路徑 7
1.3.3 掃氣模型 11
1.4 SINGLE-CYCLE TEST 16
1.5 研究目的 17
第2章 研究方法 18
2.1 數學模式 18
2.1.1 基本假設 18
2.1.2 統御方程式 18
2.1.3 紊流模型 20
2.2 邊界條件 21
2.3 數值方法 23
2.3.1 離散化 23
2.3.2 一階上風法 24
2.3.3 SIMPLE 演算法 25
2.4 格點系統 27
2.4.1 格點驗證 28
2.5 滑動格點 29
2.6 初始條件 30
第3章 結果與討論 32
3.1 二行程掃氣引擎濃度場及效率分析 32
3.2 掃、排氣行程效率分析 60
第4章 結論與未來展望 69
4.1 結論 69
4.2 未來展望 69
參考文獻 70
作者簡介 72

參考文獻

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