臺灣博碩士論文加值系統

本計劃乃是延續前期研究，對管路及突縮管之注油器噴嘴，因幾何形狀所產生兩相流空蝕現象之解析與預測。本文之研究探討是針對兩相流應用於突縮幾何外型L/D = 10之注油器內與管路系統之流場之數值計算模擬，在突縮管的例子，以不同壓差分別進行模擬分析，模擬得知在壓力差0.79Mpa雷諾數介於4.3×10e4之間為發現空蝕現象的臨界範圍，相對應的空蝕數約1.252。
並且，將此兩相流之數值模擬方法，也應用於飼水系統或核心冷卻系統之連續彎管管流中，以改善管件空蝕侵蝕，以增加安全性以及使用壽命，考慮重力影響流動的現象。工作液體為接近於飽和狀態下，工作液體通過一管路系統，當液體在管路系統中輕微低於系統溫度之飽和壓力下。或是在一彎管處，因內側管壁壓力減少，即空蝕現象可能在管路系統出現。在連續彎管的例子空蝕的臨界範圍雷諾數約1.35x10e6∼2.69x10e6之間，流場空蝕最先發生順序為4號、3號彎管，雷諾數增加為5.38x10e6時在2號彎管有出現空蝕，接著增加雷諾數為8.07x10e6時彎1號彎管也出現空蝕，相對的4號彎管之空蝕體積也越大。本文主要是以找出壓力差與及雷諾數的相互關係，和流場中發生空蝕的時機，藉以簡單地預測空蝕現象發生的條件，同時也估計可能發生空蝕現象發生的位置與分佈，另外並找出其相對關係以利於改善空蝕出現的機制。

In this work, cavitated two phase flows for nozzle and a 2D and 3D curved pipes are simulated. The benchmark test will be focused on the two-phase cavitation simulations for curved tubes and high-pressure convergent-divergent or core cooling channels of pipeline system in power plants by CFD STAR-CD solver. The geometry and operation conditions of the pipeline system will be provided by the related experiments as the test cases. The effect of operation conditions as the flow velocity pressure of pipelines on occurrence of cavitations is studied. Besides, the distributions of the occurrences of cavitation along pipe and nozzle are also discussed.
For example, Nozzle is simulated in different pressure drop. And we can know when in pressure drop 0.79Mpa that Reynolds number between 4.3×104 is critical range of cavitation. Cavitation number is correspond about 1.252.
In this case,the Reynolds number in cavitations critical range of curved pipes is between 1.35×106 and 2.69×106. The sequence of flow field cavitation is no.4 no.3. The cavitations occurs at no.2 curved pipe when Reynolds number is added about 5.38×106. And the cavitation also occurs at no.1 curved pipe when Reynolds number is added about 8.07×106. And the volume of cavitation in no.4 is more larger. In the main of this text we most find out the interrelation between pressure drop and Reynolds number and the timing of cavitation occurring. We can predict the conditions about cavitation in flow field easily. At the same time, we also can calculate the place and distribution for cavitation. Besides, we can find out the corresponding relation and then we also can improve the timing of cavitation occurring.

目 錄
致謝..... .................................................1
中文摘要...................................................2
Abstract...................................................3
圖 目 錄...................................................6
符 號 說 明...............................................10
第一章 緒論 ..............................................12
1-1 前言 .................................................12
1-2 文獻回顧 .............................................13
1-3 研究目的與方法 .......................................22
一、Case1突縮管 ..........................................22
二、Case2連續彎管型 ......................................24
第二章 物理及數學模式 ....................................27
2-1 物理現象簡介 .........................................27
2-2 空蝕係數物理意義 .....................................28
2-3 空蝕現象物理問題假設 .................................30
一、突縮管物理問題假設 ...................................30
二、連續型彎管物理問題假設 ...............................31
第三章 數值模式 ..........................................33
3-1 基本流場守恆方程式 ...................................33
3-2 標準 紊流模型 ........................................33
3-3 空蝕現象數值模式 .....................................34
第四章 結果與討論 ........................................37
4-1突縮管流場之格點獨立驗證 ..............................37
4-2 突縮管之流場與空蝕現象分析 ...........................42
4-3 突縮管之壓力差測試流場分析 ...........................45
4-4 突縮管兩相流之流場空蝕分析 ...........................47
4-5突縮管兩相流之空蝕現象暫態形式之解析說明 ..............51
4-6壓差0.79Mpa之空蝕現象暫態之連續生成圖 .................54
4-7壓差1Mpa之空蝕現象暫態之連續生成圖 ....................57
4-8壓差6Mpa之空蝕現象暫態之連續生成圖 ....................61
4-9壓差50Mpa之空蝕現象暫態之連續生成圖 ...................66
4-10壓差75Mpa之空蝕現象暫態之連續生成圖 ..................72
4-11壓差150Mpa之空蝕現象暫態之連續生成圖 .................78
4-12管路系統之連續彎管流場與空蝕現象分析 .................84
4-13連續彎管型之流場空蝕現象暫態形式之解析說明 ...........91
4-14 2D入口平均速度4m/s管路系統空蝕現象暫態之生成圖 ......94
4-15 2D入口平均速度8m/s管路系統空蝕現象暫態之生成圖 ......99
4-16 2D入口平均速度16m/s管路系統空蝕現象暫態之生成圖 .....104
4-17 2D入口平均速度16m/s管路系統空蝕現象暫態之壓力圖 .....109
4-19 3D管路系統之連續彎管模擬 ............................114
4-20 3D入口平均速度4m/s管路系統空蝕生成圖 ................119
第五章 結論 ..............................................124
參考文獻 .................................................126

[1]Lefebvre, A. H., “Atomization and spray, hemisphere publishing corporation”, pp.20-161, U.S.A., 1989.
[2]Chang, J. C., Chen, C. Y., Zhao, Z. L. and Lin, C. F., “Experimental study on the effects of injector hole geometry on atomization”, 4th Pacific International Conference on Aerospace and Technology, Vol. 1,pp. 21-23, 2001.
[3] Tamaki, N., Nishida, K., Hiroyasu, H. and Shimizu, M., “Effects of the internal flow in a nozzle hole on the breakup processes of a liquid jet”, Proc. ICLASS-97,Vol. 1, pp. 417-424, 1997.
[4] Tamaki, N., Nishida, K., Shimizu, M. and Hiroyasu, H., “Effects of cavitation and internal flow on atomization of a liquid jet”, Atomization and Sprays, Vol. 8, pp. 179-197, 1998.
[5] Nurick, W. H., “Orifice cavitation and its effect on spray mixing”, Journal of Fluids Engineering, pp.681-687, 1976
[6]Zhang, X., and Basaran, O. A., “An experimental study of dynamics of drop formation”, Phys. Fluid, Vol. 7, No. 6, June, 1995.
[7] Hiroyasu, H., Arai, M. and Shimizu, M., “Breakup length of a liquid jet and internal flow in a nozzle”, Proc. ICLASS-91, Vol. 1, pp. 275-282, 1991.
[8]Arcoumanis, C., and Andrews, R. J., “Measurement of the internal fluid flow in a diesel injector using refractive index matching”, Paper presented at an IMechE Seminar on Diesel Fuel Injection Systems, UK on 14-14 April, pp.1, 1992.
[9]Soterious, C., Andrew, R., and Smith, M., “Direct injection diesel sprays and the effect of cavitation and hydraulic flip on atomization”, SAE Paper 950080, pp.1, 1995.
[10] Chaves, H., Knapp, M., Kubitzek, A., Obermeier, F. and Schneider, T.,“Experimental study of cavitation in the nozzle hole of diesel injector using transparent nozzles”, SAE Paper 950290, pp.1, 1995.
[11]Marcus, F. H., Richard J. P., and Huimphery C., “A study of spray formed by two impinging jets”, NACATN 3835, March 1957.
[12] Tamaki, N., Nishida, K., Hiroyasu, H., and Shimizu, M., “Effects of the internal flow in a nozzle hole on the breakup processes of a liquid jet”, Proc. ICLASS-97,Vol. 1, pp. 417-424, 1997.
[13] Tamaki, N., Nishida, K., Shimizu, M., and Hiroyasu, H., “Effects of cavitation and internal flow on atomization of a liquid jet”, Atomization and Sprays, Vol. 8, pp. 179-197, 1998.
[14] Kim, J. H., Nishida, K., and Hiroyasu, H., “Characteristics of the internal flow in diesel injection”, Proc. ICLASS-97, Vol. 1, pp. 175-182, 1997.
[15] Nishida, K., Ceccio, S., Assanis, D., Tamaki, N. and Hiroyasu, H., “Characterization of cavitation flow in a simple hole nozzle”, Proc. ICLASS-97, Vol. 1, pp. 207-214, 1997.
[16] Rizk, M. A., and Elghobahsi S. E., “A two-equation turbulence model for dispersed dilute confined two-phase flow”, Int. J. Multiphase Flow, Vol. 15, pp. 119-133 (1989).
[17] Adeniji-Fashola, A., and Chen C. P., “Modeling of confined turbulent fluid-particle flows using eulerian and largrangian schemes”, Int. J. Heat Mass Transfer, Vol. 33, pp. 691-701 (1990).
[18] Issa, R. T., and Oliverira P. J., “Numerical prediction of phase separation in two-phase flow through T-junctions”, Comput. Fluids, Vol. 23, pp. 347~372 (1994).
[19] Tu, J. Y., and Fletcher, C. A. J., ”Numerical computation of turbulent gas-solid particle flow in 90。bend”, AlChE J., Vol.41, pp. 2187-2196(1994).
[20] Schmidt, D. P., Rutland, C. J., and Corradini, M. L., “A numerical study of cavitating flow through various nozzle shapes”, Engine Research Center, University of Wisconsin, Madison. 971597.
[21] Schmidt, D. P., Corradini, M. L., “Analytical prediction of the exit flow of cavitating orifices”, Engine Research Center, 1500 Engineering Dr. University of Wisconsin, Madison. WI 53706.
[22] Schmidt, D. P., Corradini, M. L., “One-dimensional analysis of cavitating orifices”, Engine Research Center, 1500 Engineering Dr. University of Wisconsin, Madison. WI 53706.
[23] Schmidt, D. P., Su, T. F., Goney, K. H., Farrell, P. V. and Corradini, M. L., “Detection of cavitation in fuel injector nozzles,” Institute for Liquid Atomization and Spray Systems Annual Conferene, Vol. 1, pp.1, 1996.
[24] Delannoy, Y., and Kueny, J. L., “Two phase flow approach in unsteady cavitation modeling”, Cavitation and Multiphase Flow Forum, ASME FED, Vol. 98, pp. 153-158, 1990.
[25] Koivula, T., “On cavitation in fluid power,” Proc. of 1st FPNI-PHD Symp. Hamburg , Vol. 1, pp. 371-382, 2000.
[26] Durst, F., and Loy, T., “Investigations of laminar flow in a pipe with sudden contraction of cross sectional area”, Computers & Fluids Vol. 13, No. 1, pp.15-36, 1985.
[27] Ohrn, T. R., Senser, D. W., and A. H. Lefebvre, “Geometrical effect on discharge coefficients for plain-orifice atomizers”, Atomization and Sprays, vol., no. 2, pp.137-153, 1991.
[28] Koo, J. Y., and Martin, J. K., “Near-Nozzle Characteristics of A Transient Fuel Spray”, Atomization and Sprays, vol. 5, pp.107-121, 1995.
[29] He, L., and Ruiz, F., “Effect of cavitation on flow and turbulence in plain orifice for high-speed atomization”, Atomization and Sprays, vol. 5, pp.569-584, 1995.
[30] Schmidt, D. P., Rustand, C. J., and Corradini, M. L., “A fully compressible, two-dimensional model of small, high-speed, cavitating nozzles”, Atomization and Sprays, vol. 9, pp.255-276, 1999.
[31] Kine, M. C., Woodward, R.D., Burch, R.L., Cheung, F.B., and Kuo, K. K., “Imaging of impinging jet breakup and atomization processes using copper-vapor-laser-sheet-illuminated photography”, Chemical Propuisi- on , Non-intrusive Combustion Diagnostics , May 1993, The Netherlan- ds.
[32] 卓英吉,“以數值方法探討注油器管內流場之空蝕現象”, 國立成功大學航空太空工程研究所碩士論文, 1997.
[33] 楊授印, “以數值方法探討噴流機構內流場空蝕現象” , 國立成功大學航空太空工程研究所碩士論文, 1998.
[34] 洪健元,”內流場空蝕現象之初步數值模擬”, 中華大學機械與航太工程研究所碩士論文, 2000.
[35] Huang, Z., Shao, Y. M., Shiga, S., Nakamura, H., and Karasawa T., “The role of orifice flow pattern in fule atomization “ ICLASS-94 Rouen , France , July 1994,pp 86-93
[36] Kuensberg Sarre, C., Kong, S. C. and Reitz, R. D., “Modeling the effects of injector nozzle geometry on diesel sprays“, SAE Paper 1999-01-0912, 1999.
[37] Computational Fluid Dynamics Softwasre , “STAR-CD Version 3.10 User Guide”, 1999 Computational Dynamics Limited.
[38] Computational Fluid Dynamics Softwasre , “STAR-CD Version 3.10 Tutorial Manual vol.1”, 1999 Computational Dynamics Limited.
[39] Computational Fluid Dynamics Softwasre , “STAR-CD Version 3.10 Tutorial Manual vol.2”, 1999 Computational Dynamics Limited.
[40] Computational Fluid Dynamics Softwasre , “STAR-CD Version 3.10 User Guide”, 1999 Computational Dynamics Limited.
[41] Giese, T., and Laurien, E., ,“A three dimensional numerical model for the analysis of pipe flows with cavitation” Institute for Nuclear Technology and Energy Systems (IKE) University of Stuttgart.
[42] Kubota, A., Kato, H., and Yamaguchi, H. 1992. ‘A new modelling of
cavitating flows: a numerical study of unsteady cavitation on a hydrofoil section’, J. Fluid. Mech., 240, pp. 59-96.
[43]曹家誌,”兩相流管件侵蝕之現象之數值解析”中華大學機械與航太工程研究所碩士論文, 1999.
[44]楊添智,”兩相流體空蝕現象之數值初步探討”中華大學機械與航太工程研究所碩士論文, 2002.