跳到主要內容

臺灣博碩士論文加值系統

(35.153.100.128) 您好!臺灣時間:2022/01/22 07:48
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:李明龍
研究生(外文):Ming-Long Lee
論文名稱:澆注過程之模式分析
論文名稱(外文):Modeling Analysis of Filling Processes
指導教授:趙隆山
指導教授(外文):Long-Sun Chao
學位類別:碩士
校院名稱:國立成功大學
系所名稱:工程科學系碩博士班
學門:工程學門
學類:綜合工程學類
論文種類:學術論文
論文出版年:2002
畢業學年度:90
語文別:中文
論文頁數:99
中文關鍵詞:澆注數值分析
外文關鍵詞:FillingNumerical analysis
相關次數:
  • 被引用被引用:2
  • 點閱點閱:348
  • 評分評分:
  • 下載下載:68
  • 收藏至我的研究室書目清單書目收藏:0
澆注過程是屬於含有自由液面之流場的暫態問題。澆注與過程的數值模擬有助於瞭解模穴充填時金屬液流動的情形,對於鑄件品質的控制及鑄模的設計都有很大的幫助。
本文以數學模式來模擬金屬液於模穴之澆注過程。在澆注方面,同時考慮金屬液與空氣。流場部分,使用POWER-law法對統御方程式進行離散,並利用SIMPLE法及雙區計算模式來求解速度場。求解守衡標量方程式,以決定自由液面區的位置與型態。
探討澆注過程中,流體在模穴中流動的情形及自由液面的變化情形,本文以底澆和側澆,來比對不同的澆注位置流場的流動情形。於流場之分析中,對SIMPLE法與SIMPLER法作比較,發現後者比前者較易得到收斂速度場。計算所得之自由液面型態大致與文獻上吻合。在側澆中速度低的充填過程中,重力效應大於慣性力,容易產生潰流而影響上游流場;速度比較快的充填過程中,慣性力大於重力效應,金屬液沿著邊牆充填不會影響上游流場。但在底澆中就比較不會有這類情形,但如果速度過快,就會產生金屬液體的不穩定,而造成捲氣等缺陷,待凝固後就會產生氣孔。
本文除了在數值模式的探討及分析比對外,也希望能將此模式應用在實際澆注過程中,所以以一工字型鑄模為例。在工字型鑄模中,金屬液受到下縮孔和上擴口的影響,比矩型鑄模,流動較為平順,不過當速度增加時,金屬液流動與液氣界面就會較不穩定。
ABSTRACT
A filling process is a transient flow problem with time-varying free surface. The numerical simulation can help us to understand the flow field of a filling process, which can assist the mold design and the quality control of a casting process.
In this paper, a mathematical model, in which both liquid metal and air were considered, was built to simulate the filling processes in a mold cavity. The POWER-law was used to derive the finite difference equations of the flow field, and the SIMPLE algorithm was applied to solve the velocity field. By utilizing the Van Leer second-order scheme, the conserved scalar equation was solved to determine the position and profile of liquid/air interface.
In the beginning of this study, the computing results of the SIMPLE algorithm for a channel flow were compared with those of the SIMPLER one. The latter is easier to obtain convergent solutions than the former. In the analysis of filling process, the flow fields of both side- and bottom-fillings of a rectangle mold cavity were analyzed by the proposed model. The profiles of free surface of side filling are similar to those in the literature. For side-filling, when the gravity force is larger than the inertia force, the flow front is easier to break up and affect the upstream. On the contrary, the flow front will go up along the mold wall and will not affect the upstream. The flow front of bottom-filling is more stable than in side-filling. However, the higher inlet velocity would make the front of bottom-filling less stable. Finally, a more practical case, the flow field of filling an I-shaped mold cavity, was investigated.
目錄
摘要 I
ABSTRACT Ⅰ
目錄 IV
圖目錄 VII
表目錄 X
符號說明 XI
第一章 緒 論 1
1.1研究動機 1
1.2文獻回顧 3
1.3研究方法 6
第二章 理論分析 7
2.1基本假設 7
2.2控制方程式 8
2.3流場邊界條件 10
第三章 數值分析 12
3.1交錯網格與控制體積的設置 12
3.2 差分方程式與解法 13
3.3數值方法 15
3.3.1 SIMPLE運算法 15
3.3.2 SIMPLER運算法 18
3.4自由液面的追蹤 20
3.5邊牆之邊界條件 23
3.6澆注模式之求解過程 24
第四章 結果與討論 26
4.1流場數值測試與討論 26
4.1.1測試Van-Leer法的可行性 26
4.1.2測試SIMPLE及SIMPLER法的可行性 27
4.1.3 SIMPLE及SIMPLER法之比較 28
4.2網格、猜初值與鬆弛因子對數值的影響 28
4.2.1網格對數值的影響 28
4.2.2 SIMPLE及SIMPLER法猜初值對數值的影響 29
4.2.3鬆弛因子對數值的影響 29
4.3網格的測試與比對 30
4.4澆注流場之數值比對 32
4.4.1水壩崩流分析 32
4.4.2側澆充填分析 33
4.4.3底澆充填分析 34
4.4.4工字型的應用 36
第五章 結論 38
參考文獻 40
附錄 A 83
附錄B 90
附錄C 93
附錄D 95
參考文獻
Amsden, A. A. and Harlow, F. H., "A Simplified MAC Technique for Incompressible Fluid Flow Calculation," Tech. Report LA-4370, Los Alamos Scientific Laboratory (1970).
Carslaw, H. S. and Jaeger, J. C., "Conduction of Heat in Solids," 2nd ed., Oxford at the Clarendon Press, pp. 282-283 (1959).
Crank, J., "Free and Moving Boundary Problems, " Oxford Uni. Press, Oxford (1984).
Chan, K. S., Pericleous, K. and Cross, M., "Numerical Simulation of Flow Encountered during Mold-Filling," Applied Math. Modelling, Vol.15, pp. 624-631 (1991).
Date, A.W., "A Strong Enthalpy Formulation for the Stefan Problem," International Journal of Heat and Mass Transfer, Vol. 34, pp. 2231-2283 (1991).
Harlow, F. H. and Welch, J. E., "Numerical Calculation of Time-Dependent Viscous Incompressible Flow of Fluid with Free Surface," Phys. Fluids Vol. 8, pp. 2182-2189 (1965).
Hirt, C. W. and Nichols, B. D., "Volume of Fluid (VOF) Method for the Dynamics of Free Boundaries," J. Comput. Phys., Vol. 39, pp. 201-225 (1981).
Hsiao, J. S., "An Efficient Algorithm for Finite Difference Analysis of Heat Transfer with Melting and Solidification," Numerical Heat Transfer, Vol. 8, pp. 653-666 (1985).
Liu Jun and Spalding, D. B., "Numerical Simulation of Flows with Moving Interface," PCH., Vol. 10, pp. 625-637 (1988).
Martin, J. C. and Moyce, W. J., Phil. Trans. Roy. Soc. London, pp.244-312 (1952).
Nichols, B. D., Hirt, C. W. and Hotchkiss, R. S., "SOLA-VOF: A Solution Algorithm for Transient Fluid Flow with Multiple Free Boundaries," Tech. Report LA-8355, Los Alamos Scientific Laboratory (1980).
Pao, R. H. F., "Fluid Dynamics," pp.148-149, Charlese E. Merrill Books, Inc., Columbus, Ohio, U.S.A (1967).
Pantanker, S. V., "Numerical Heat Transfer and Fluid Flow," Hemisphere Publishing Co.,New York, U.S.A (1980).
Rappaz, M., "Modelling of Microstructure Formation in Solidification Processes, " International Materials Reviews, Vol. 34, No. 3, pp. 93-123 (1989).
Shah, R. K., and A. L. London,"Laminar Flow Forced Convection in Ducts"Academic,New York(1978).
Shah, R. K., "A Correlation for Laminar Hydrodynamic Entry Length Solution for Circular and Noncircular Ducts",J. Fluids Eng., Vol.100,p.177-179(1978).
Suhas, V. Patankar, "Numerical Heat Transfer and Fluid Flow," Hemisphere Publishing Co., New York (1980).
Swaminathan, C. R. and Voller, V. R., "A Time Implicit Filling Algorithm," Math. Modeling, Vol. 18, pp. 101 (1994).
Tszeng, T. C., Im, Y. T. and Kobayashi, S., "Thermal Analysis of Solidification by The Temperature Recovery Method," Int. J. Mach. Tools Manufact. Vol. 29. No. 1, pp. 107-120 (1989).
Van Leer, B., "Towards the Ultimate Conservative Difference Scheme. IV: A New Approach to Numerical Convection," J. Comput. Phys., Vol. 23, pp. 276-299 (1977).
Voller, V. R., "First Implicit Finite-difference Method for the Analysis of Phase Change Problem, " Numerical Heat Transfer, Part B, Vol. 17, pp. 155-169 (1990).
Voller, V. R., and Swa, C. R., "General Source Based Method for Solidification Phase Change," Numerical Heat Transfer, Part B, Vol.19, pp. 175-189 (1991).
Welch, J. E., Harlow, F. H., Shannon, J. P. and Dally, B. J., " The MAC Method, A Computing Technique for Solving Viscous, Incompressible, Transient Fluid Flow Problems Involving Free Surfaces," Tech. Report LA-3425, Los Alamos Scientific Laboratory (1966).
蔡懷寧,楊秉儉,蘇俊義,"型腔充填過程的三維流動數值模擬",鑄造 (1996).
廖欽彬,"不同障礙物分佈對平行板層流場影響之數值分析",碩士論文,國立海洋大學機械與輪機工程系 (1998)
張恭豪,"澆鑄過程之三維數值分析",碩士論文,國立成功大學工程科學系 (1998).
彭勳章,"澆注與凝固過程之三維數值分析",碩士論文,國立成功大學工程科學系 (1999).
劉曜嘉,"澆注過程之分析-守衡標量法之應用",碩士論文,國立成功大學工程科學系 (2000).
廖學專,"澆注與凝固過程之數值分析",碩士論文,國立成功大學工程科學系 (2001).
連結至畢業學校之論文網頁點我開啟連結
註: 此連結為研究生畢業學校所提供,不一定有電子全文可供下載,若連結有誤,請點選上方之〝勘誤回報〞功能,我們會盡快修正,謝謝!
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top