臺灣博碩士論文加值系統

　　離心泵葉輪為三維扭轉曲面，其流體沿著曲面來改變流向或改變流體速度與壓力，促使能量提昇。而干涉程度大、形狀複雜、葉片外廓建構不易、多軸加工困難與複雜的流場特性，涵蓋著流場分析與五軸加工技術；同時，其相關技術亦為國防科技發展的關鍵技術。國內技術之獲得相當昂貴且不易。如何將離心式葉輪精確地分析與加工設計，突破瓶頸並有效提昇其性能，顯然是一項重要的課題。
　　本研究有鑑於此，將創成加工理念的體積掃掠法導入葉輪設計之前，建構流體葉輪外形，建立加工方法並討論之；同時以解析式三次仿線與數值曲線有理式B仿線分別合成葉片空間曲線，將曲線參數、流場參數與加工參數作結合，分別比較不同的曲線葉形對流場效能之影響；並針對第四軸旋轉角與葉頂間隙對流場的影響加以討論。加工規劃方面，本研究針對不同曲線的加工運動分析做討論，並以扇形高度的概念來規劃刀具路徑；以向量幾何研判加工路徑是否與葉片干涉；以主曲率半徑決定刀具直徑的選取與葉片表面過切與否。最後對加工規劃結果之合理性做一討論。

　　The centrifugal impeller is a three-dimensional twisted surface. The energy is generated by velocity and pressure converting. The centrifugal impeller has some hard works, such as the interference of machining, the complex shape of blades, the difficulty in setting up blades and multi-axial machining, and the complicated fluid characteristics. That includes the flow simulation method and five-axial machining technology, and the related technique is also the key point of national defense industry. It is difficult and expensive to get the technique in Taiwan. Obviously, it is an important business that how to design and to analyze the performance of centrifugal pump accurately. There has many obstacles to overcome.
　　Therefore, the volume swept method based on the generated machining concept is advanced by the design of centrifugal impeller in this research. And it is discussed that how to create the profile of centrifugal impeller and machining method. The analytical spline and the rational B-spline will be introduced for the space-curve construction and curve parameters, fluid parameters, and machining parameters will be combined. Then it is found that the influence of curve on the performance of flow field. It is discussed that the fluid characteristics of tip clearance, the influence of tip clearance, and the twisted angle of impeller blades on the performance of flow field. Machining kinetic analysis of different curve is discussed in this research, and planning of tool path was worked by the concept of scallop height. At the same time, this research uses vector analysis to determine that the possibility of collision, and detects the possibility of over-cutting by the principal curvature. Finally, the performance of machining planning was estimated in this research.

中文摘要…………………………………………………I
英文摘要…………………………………………………II
誌謝………………………………………………………III
目錄………………………………………………………V
表目錄……………………………………………………VIII
圖目錄……………………………………………………IX
符號說明…………………………………………………XIV

第一章　 緒論……………………………………………1
1-1研究動機及目的………………………………………1
1-1.1泵之種類……………………………………………1
1-1.2產業現況概述………………………………………3
1-1.3遭遇之困難與挑戰…………………………………4
1-2本文架構………………………………………………5
1-3研究流程………………………………………………5
1-4文獻回顧………………………………………………6
第二章 離心式葉片的設計與五軸加工………………9
2-1離心泵之設計參數……………………………………9
2-2刀具路徑與葉片外廓的產生…………………………13
2-2.1均線位置產生………………………………………13
2-2.2刀具路徑產生………………………………………14
2-2.3葉片外廓產生………………………………………16
2-3葉片幾何與曲線之關係………………………………17
2-3.1三次仿線合成………………………………………18
2-3.2 有理式B仿線合成…………………………………19
2-4入出口角與曲線之關係………………………………23
2-5刀具路徑的修正………………………………………24
第三章 流場數值模擬…………………………………26
3-1基本假設………………………………………………26
3-2統御方程式……………………………………………26
3-3紊流模式………………………………………………28
3-3.1紊流模式……………………………………………28
3-3.2壁面函數……………………………………………30
3-4數值方法………………………………………………31
3-4.1平均雷諾Navier Stokes方程式離散 ……………31
3-4.2通量元素……………………………………………32
3-4.3上風差分法…………………………………………33
3-4.4數值網格建立………………………………………35
3-4.5邊界條件設定………………………………………36
第四章 加工規劃………………………………………38
4-1曲面彎曲程度表示……………………………………38
4-2扇形高度………………………………………………41
4-3餘料下刀點……………………………………………42
4-4加工干涉研判…………………………………………43
第五章 結果與討論……………………………………45
5-1 解析式仿線與有理式B仿線之流場比較……………45
5-2第四軸旋轉角對流場的影響…………………………46
5-3葉頂間隙之流場分析…………………………………49
5-4加工規劃結果…………………………………………50
5-4.1葉片表面主曲率半徑研判…………………………50
5-4.2進給速度與進給加速度分析………………………52
5-4.3粗加工規劃結果……………………………………53
第六章 結論與未來展望………………………………54
6-1結論……………………………………………………54
6-2未來展望………………………………………………55
參考文獻 …………………………………………………57
附錄 有理式B仿線之微分形式 …………………………118
自述 ………………………………………………………119

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