臺灣博碩士論文加值系統

本研究主要探討不同噴嘴流道設計及不同材料參數對於粒徑大小的影響。研究使用Ansys/Fluent針對三種不同噴嘴流道設計(內縮2 mm、水平0 mm、凸出4 mm)進行流場分析，首先分析不同邊界是否會影響模型流場，分析結果對於流場氣體最大速度相差0.003 %，但是流線上截然不同，要符合現實實驗須以兩側為牆壁。
針對內縮2 mm、水平0 mm、凸出4 mm噴嘴在不同進氣壓力下進行模擬，結果得知，隨進氣壓力增大，氣流所產生的迴流區越大，三種噴左設計達到尾流閉鎖壓力分別為48 bar、50 bar、57 bar，增加粒徑進行模擬，內縮2 mm與凸出4 mm在發生尾流閉鎖後平均粒徑有上升趨勢，推測是噴嘴設計及氣體出口與撞擊點距離很長，動能損失較多，而水平0 mm平均粒徑整體呈現變小趨勢。
針對粒徑在不同溫度、不同表面張力以及不同材料下進行模擬分析，結果顯示，以溫度來看，隨著粒徑溫度越高，平均粒徑呈現變小趨勢。以表面張力來看，材料表面張力越小所產生的平均粒徑越小，反之越大。以不同材料方面來看，模擬粒子溫度設定為1100 ℃，在此溫度下， 銅進入流場溫度快速降至熔點溫度1080 ℃以下，粒徑平均較大，材料鋁與材料錫因熔點低，粒徑平均較小。

This study focuses on the effect of different nozzle runner designs and different material parameters on the particle size. The study uses Ansys/Fluent to analyze the flow field for three different nozzle runner designs (2 mm internal shrinkage, 0 mm horizontal, and 4 mm projection), and first analyzes whether different boundaries affect the model flow field.
Simulations were conducted for 2mm inlet, 0mm horizontal, and 4mm projection nozzles at different inlet pressures, and the results showed that as the inlet pressure increases, the larger the backflow area generated by the gas flow, and the three nozzle designs reach the wake closure pressure of 48 bar, 50 bar, and 57 bar, respectively, and increase the particle size for simulation, the average particle size of 2mm inlet and 4mm projection in the wake closure has increased It is presumed that the nozzle design and gas exit distance from the impact point are very long, which results in more kinetic energy loss, while the overall average particle size of 0mm is decreasing.
The simulations were conducted for different temperatures, different surface tensions and different materials, and the results showed that, in terms of temperature, the average particle size tends to decrease as the temperature of the particle size increases. In terms of surface tension, the lower the surface tension of the material, the smaller the average particle size produced, and vice versa. In terms of different materials, the melting point of copper is 1080 °C, and the particle temperature is set to 1100 °C. Under this temperature, the temperature of copper entering the flow field drops rapidly to below 1080 °C, and the average particle size is large.

摘要 II
ABSTRACT IV
謝誌 VI
目錄 VII
表目錄 IX
圖目錄 X
符號索引 XI
第1章 緒論 2
1.1 前言 2
1.2 文獻回顧 3
1.3 研究動機 6
第2章 研究方法 8
2.1 基本假設 8
2.2 研究流程 8
2.3 統御方程式 9
2.3.1 連續方程式(Continuity equation) 9
2.3.2 動量方程式(Momentum equation) 10
2.3.3 能量方程式(Energy equation) 11
2.3.4 紊流方程式(Turbulence equation) 11
2.3.5 理想氣體方程式 (Ideal Gas Equation) 12
2.3.6 福祿數（Froude number） 12
2.4 研究方法 13
2.4.1 噴嘴尺寸與流場尺寸 13
2.4.2 網格系統 15
2.4.3 邊界條件 17
第3章 結果與討論 18
3.1 相同模型不同邊界模擬結果 20
3.2 不同噴嘴設計模擬結果 26
3.3 不同材料模擬結果 38
3.4 不同粒子溫度模擬結果 40
3.5 不同表面張力模擬結果 41
第4章 結論 46
第5章 未來展望與建議 48
參考文獻 49

1.S.P. Mates, S.D. Ridder, F.S. Biancaniello, Comparison of the Supersonic Length and Dynamic Pressure Characteristics of Discrete-Jet and Annular Close-Coupled Nozzles Used to Produce Fine Metal Powders, in: Proceedings of the 129th Annual Meeting & Exhibition of the Minerals, Metals & Materials Society. Nashville, USA, pp.71–81, 2000.
2.LI Xin, WANG Yong_xiang , Study on the Effect of Atomization Parameters on the Granularity of Metal Powder[J]. Jiangxi Nonferrous Metal ,16(3) ,pp.27-29,2002
3.J. Ting, M W. Peretti, W B. Eisen, “The effect of wake-closure phenomenon on gas atomization performance,” Materials Science and Engineering, A326 pp. 110–121, 2002.
4.Xu Q, Cheng D, Trapaga G, Yang N, Lavernia EJ. Numerical analysis of fluid dynamics of an atomization configuration. J Mater Respp,pp.156–66,2002.
5.Chengsong Cui, Fuyang Cao, Qingchun Li, “Formation mechanism of the pressure zone at the tip of the melt delivery tube during the spray forming process,” Journal of Materials Processing Technology, Vol. 137 pp. 5-9, 2003.
6.J. Ting, IE. Anderson, “A computational fluid dynamics (CFD) investigation of the wake closure phenomenon,” Materials Science and Engineering, A 379, pp. 264-276, 2004.
7.Lang M, Rist U, Wagner S. Investigations on controlled transition development in a laminar separation bubble by means of LDA and PIV. Exp Fluids(36) ,pp.43–52,2004.
8.P. McGuinness, W. Drenckhan, D. Weaire , “The optimal tap: three. Dimensional nozzle design,” Journal of Physices D: Applied Physices, Vol. 38, Issue. 4, pp. 3382-3386, 2005.
9.S.P. Mates, G.S. Settles, A study of liquid metal atomization using close-coupled nozzles, part 2: atomization behavior, At. Sprays 15, pp.41–60, 2005.
10.N. Zeoli, S. Gu, “Numerical modelling of droplet break-up for gas atomization,” Computational Materials Science, Vol. 38, pp. 282-292,
2006.
11.Mullis AM, Adkins NJ, Huang Z, Cochrane RF. Quantitative high frame rate analysis of the spray cone geometry during close-coupled gas atomization. In: Third international conference on spray deposition and melt atomization SDMA2006, Bremen, Germany; 4–6th September 2006.
12.R. Ünal, “Investigation on metal powder production efficiency of new convergent divergent nozzle in close coupled gas atomisation,” Powder Metallurgy, Vol.50, No. 4, 2007.
13.Unal R. Improvements to close coupled gas atomization nozzle for fine powder production. Powder Metall50(1), pp.66–71, 2007.
14.M. Jeyakumar, G. S. Gupta, S. Kumar, “Modeling of gas flow inside and outside the nozzle used in spray deposition,＂Journal of materials processing technology, Vol. 203, pp. 471-479, 2008.
15.Planche M.P., Allimant A., Bailly Y., Dembinski L. and Coddet C., “Progress in gas atomization of liquid metals by means of a De Laval nozzle,” Powder Technology, PTEC-07221, 2008
16.Tong M, Browne DJ. Modelling compressible gas flow near the nozzle of a gas atomiser using a new unified model. Comput Fluids(38) , pp.1183–90, 2009.
17.R. Ünal, O. Aydin, “Experimental and numerical modeling of the gas atomization nozzle for gas flow behavior,” Computer and Fluids, Vol. 42, pp.37-43, 2011.
18.O. Aydin, R. Unal, “Experimental and Numerical Modeling of the Gas Atomization Nozzle for Gas Flow Behavior,” Computer & Fluids, Vol. 42, Issue. 1, pp. 37-43, 2011.
19.S. Motaman, A. M. Mullis, R. F. Cochrane, “Use of Computational Modelling For Investigation the Effect of Melt Delivery Nozzle Tip Length on Gas Flow Separation in Supersonic Gas Atomization,” International Conference on Liquid Atomization and Spray Systems, 2012.
20.CAO Jian-ming , ZHU Hui , GUO Guang-xiang , WANG Zhen-ping , CHEN Hai-long , LU Lin-chun , LI Ming-long.Study on air assistant to improve quality of droplet atomization[J].Experiments and Measur in Fluid Mechanics, 27(1)pp.56-60,87,2013.
21.E. Urionabarrenetxea, J.M. Martín, A. Rivas, I. Iturriza, F. Castro, Experimental study and simulation of the gas flow in the atomisation chamber during close-coupled gas atomisation, Proceedings of the International Powder Metallurgy Congress and Exhibition, Euro PM , European Pow , 2013.
22.R. Tamura, T. Osada, K. Minagawa, T. Kohata, M. Hirosawa, K. Tsuda, K. Kawagishi, Machine learning-driven optimization in powder manufacturing of Ni co based superalloy, Mater. Des. 109290 (2020).
23.D. Beckers, N. Ellendt, U. Fritsching, V. Uhlenwinkel, Adv. Powder Technol(31)。pp.300‒311,2020。