臺灣博碩士論文加值系統

本論文是有關微流道之流力及熱傳性質分析，與LIGA製程技術上的研究。微流道流動時其流力與熱傳參數為雷諾數(Re)和裴立數(Pe)，因為微流道之尺寸微小，對應之Re與Pe也相對很小。要以實驗方式觀察微流道內部的流動行為也幾乎不可能，在此微流道中Re的階次為10-4。
為了觀察如此複雜的對流流動系統，吾人建立了一套實驗測試模型，其Re略大於10-2。幸運的是，當Re為10-4到10-2之間，其流動的行為理論上可視為相同。因此，我們預期此二者會有相同的流動特性。吾人完成一個Re由10-8到1之間的數值解，證實在Re為10-4到10-2之間其流動特性相同。至於測試模型的Pe則可調整當與微流道相近。
微流道的一項重要應用是在紡織工業中的微型抽絲紡口(micro spinneret)，PET為超細纖維所使用的一種原料，本論文對於PET在不同溫度變化關係係以冪次律(power law)來表示，並計算出微流道中流函數(stream function)、渦度(vorticity) 與溫度分布，流道內壁上之摩擦係數和紐塞數(Nu)亦已求得。在測試模型實驗中，吾人以甘油作為工作流體，沿流動方向進行壓力分布量測，並以20-40m的PE粉末對此流場進行觀察。
LIGA製程技術包含微影(lithography)、電鑄(electroforming)及模造(molding)，在製造大量及高精確度的微小結構上，是一項新興技術。使用LIGA製程技術製造微流道還有高深寬比(aspect ratio)與流道幾何形狀的易變性(flexibility)等優點。吾人使用紫外光(UV, ultraviolet)曝光得到金(Au)的光罩(mask)，之後經X射線曝光可得到一高深的PMMA微結構。經過電鑄、拋光(polishing)與蝕刻(etching)，一個微型模(mold)就完成了。此微型模在經過模造及電鑄過程後便成為微流道。紡織工業需要大量具有高深寬比和不同流道幾何形狀的微型抽絲紡口，所以這在LIGA製程技術上是一項理想的應用。

This dissertation is concerned with the analysis of flow and heat transfer characteristics and LIGA fabrication technique for a micro nozzle. The flow and heat transfer parameters in the nozzle flow are the Reynolds number and the Peclet number. The extremely small size of micro nozzle yields small values of Re and Pe. It is almost impossible to observe the flow behavior experimentally inside the micro nozzle. The order of Reynolds number in the micro nozzle is usually less than 10-4.
To visualize the complex convective flow system, an experimental test model was built. The Reynolds number in the test model is not less than 10-2. Fortunately, the flows with Re= 10-4 to 10-2 are in the same flow regime of low Reynolds number. Therefore, it is expected to have the same flow characteristic. A numerical solution covers the range of Re=10-8 to 1.0 confirms that flow characteristics for Re=10-4 and 10-2 are the same. The value of Peclet number in the test model can be adjust to the value similar to that in the micro nozzle.
An important application of the micro nozzle is for micro spinneret in textile industry. Polyethylene terephthalate (PET) is the material of the micro fiber. The relationship of shear rate and viscosity of PET at various temperature levels is correlated by a power law. The stream function, vorticity, and temperature distributions in a micro nozzle are calculated. The friction factor and Nusselt number analyses in the micro nozzle are also carried out. In the test model, glycerin was used as the working fluid to simulate the flow. The pressure distribution along the flow direction was measured and the flow pattern was visualized by using polyethylene (PE) powder of 20-40mm.
could be expected after this exploration.
LIGA technique including lithography, electroforming and molding processes, is a new technique for fabricating large number and high precision microstructures. The other advantages of using LIGA technique in making nozzles are its capability of high aspect ratio and flexibility of nozzle geometry. One uses an UV(ultraviolet) exposure to obtain Au mask for X-ray exposure to make a deep PMMA microstructure. After the processes of electroforming, polishing and etching, a production mold can be obtained. The production mold then can be used for making the nozzles by molding and electroforming processes. The textile industry requires a large quantity of micro spinnerets with high aspect ratio and different nozzle geometry. It is an ideal application of LIGA technique.

ABSTRACT‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥i
ACKNOWLEDGEMENTS‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥iii
CONTENTS‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥iv
LISTS OF TABLES‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥vii
LISTS OF FIGURES‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥viii
NOMENCLATURE‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥x
I. INTRODUCTION‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥1
1.1 Theoretical Analysis‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥1
1.2 LIGA Fabrication Technique‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥2
1.3 The Structure of Present Study‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥4
II. THEORETICAL ANALYSIS‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥6
2.1 Governing Equations‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥6
2.2 Boundary Conditions‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥9
III. NUMERICAL METHODS‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥11
3.1 Grid System‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥11
3.2 Finite Difference Method‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥11
3.3 Solution Procedures‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥13
IV. EXPERIMENTAL APPARATUS AND PROCEDURES‥‥‥‥‥‥‥‥15
4.1 Pressure Measurements‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥15
4.2 Flow Visualization‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥16
V. LIGA FABRICATION TECHNIQUE‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥17
5.1 LIGA Spinneret Approach‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥17
5.2 Deep X-ray Lithography‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥17
5.2.1 Substrate preparation‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥17
5.2.2 Ultra-deep LIGA process‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥18
5.2.3 Conformal mask‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥20
5.3 Die Electroforming‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥22
5.3.1 Nickle plating‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥22
5.3.2 Alloy plating‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥24
5.4 Micro Injection Molding‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥25
5.5 Spinneret Electroforming‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥26
5.5.1 Surface treatment‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥27
5.5.2 Composite plating‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥28
VI. RESULTS AND DISCUSSION‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥29
6.1 PET Viscosity Correlation‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥29
6.2 Pressure Measurement‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥30
6.3 Numerical Solution‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥30
VII. CONCLUDING REMARKS‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥35
REFERENCES‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥37
TABLES‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥40
FIGURES‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥42
APPENDIX‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥79

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