臺灣博碩士論文加值系統

摘要

本文以數值模擬分析，探討各種配置的側向噴流對管狀突張式後續燃燒器內流場混合之情況，採用 紊流模式，以控制體積積分法，建立有限差分方程式，按SIMPLEST運算程序求解。並於各種固定配置狀況下，變更噴流與主流之動量流通率比，以觀察噴流動量之改變對混合流場的影響，並研究具偏斜角之側向噴流進氣方式對混合流場的影響。
經模擬顯示，對此種突張圓管之侷限流場而言，邊壁的捲增效應對混合率的提升有極大的助益，當動量流通率比J由1提升至2時，可明顯看出當J=2的混合率較J=1時有著顯著的提升(約10﹪)。且混合率並非隨著動量流通率比增加而升高，反而會有降低的趨勢，在2噴流對衝配置中，混合率最高值發生在J=4；而於多噴流配置中，當J=2時則有最佳之混合情形。在具偏斜角之側向噴流情況中，當偏移角度小時(≦10度)，將有助於流場更快速的混合，但若偏斜角度再增加，則會導致混合情形變差。藉由此文之模擬結果，不僅可探尋較佳的噴射流配置及J值，避免不必要的能量浪費，且可由流場速度向量圖和溫度分佈圖預測流場混合變化，進而有效的縮短後續燃燒器的尺寸長度。


關鍵字: 紊流模式、動量流通率比、偏斜角、突張圓管、
捲增效應、混合率

Abstract
In this study, a computational fluid dynamics（CFD）code, PHOENICS, is used to simulate the flowfield of the transverse jets with angle of inclination impacting each other on the three-dimensional confined cross flow. It adopts the two-equations turbulence model and the control-volume integration formula for finite difference and SIMPLEST algorithm to find more flowfield morphological characteristic of the various mixing configuration of the transverse jets. In the different jets configuration, the velocity vector, temperature, pressure,and the situation of mixing between the cross flow and opposed jets will be studied one by one.
For S/D=8 and S/D=6 case，the results show that the angle of inclination of transverse jets between and would produce the eddies which they are similar to form of 8. Because of these eddies have very strong efficacy and stay in the flowfield for a long time, the overall mixing rate will be nice. When the angle of inclination between and , the angle of jets slope very much and the jets fluid almost collect on the up-plane and down-plane in every kinds of jets configuration.The heat transfer is much worse between jets flow and cross flow at the center of duct, so the overall mixing rate decrease very much. In terms of the momentum flux ratio up to J=20, we can observe the jets mixing rate the same as J =30 at the downstream location 0f X/H=2.We can choose the low momentum flux ratio to economize energy. In cases of small spacing （S/D=4）overall mixing rate and pressure much higher than large spacing（S/D=8）.

Keywords：sequential burner, momentum flux ratio, mixing rate, angle 0f inclination of transverse jets

中文摘要…………………………………………………………...……..i
英文摘要………………………………………………………………....ii
目錄…………………………………………………………….………..iii
表目錄…………………………………………………………….……...v
圖目錄………………………………………………………….………..vi
符號說明………………………………………….…………..………..viii

第一章緒論…………………………..………………………………....1
1.1 前言………………………….………………………………….1
1.2突張式後續燃燒器流場簡介……………………………………1
1.3 研究動機與目的………………………………………….…….2
1.4 文獻回顧…………………………………………….………….3

第二章計算方法與物理模式………………………………………..…7
2.1 物理模式……………………………………………………….7
2.3 控制方程式…………………………………………………….7
2.4 邊界條件……………………………………………………...10

第三章 數值方法……………………………………………………..12
3.1 簡介…………………………………………………………...12
3.2 網格點系統…………………………………………………...12
3.3 差分方程式的建立…………………………………………...13
3.3.1 數值分析………………………………………………13
3.3.2 差分方程式……………………………………………13
3.3.3 混合體系法……………………………….…………..14
3.4 求解程序……………………………………………………...16
3.4.1 SIMPLE求解法………………………………………..17
3.4.2 SIMPLEST與SIMPLE求解法之比較……………….19
3.4.3鬆弛因子……………………………………………….20
3.4.4收斂條件……………………………………………….20
3.4.5數值模擬流程………………………………………….21
第四章 結果與討論…………………………………………………..23
4.1 兩噴嘴對衝配置……………………………………………...24
4.2 多噴嘴配置…………………………………………………...25
4.3 兩噴嘴偏斜進氣配置………………………………………...27

第五章 結論與建議…………………………………………………..29

參考文獻………………………………………………………………..31

1.邱耀平，“噴流在一受侷限流場之衝擊過程特性研究”,The Chinese Journal of Mechanics,Vol.13,No.2,June 19972.L. H. Back and E. J. Roschke,“Shear-layer Flow Regimesand Wave Instalilityies and Reattchment Length Downstream of an Abrupt Circular Channel Expansion”J. of Appl. Mech. Trans. ASME,Vol.94, pp. 667-681,1972.3.古旭輝“低音速突張管流場研究”,國立清華大學碩士論文,1980.4.K.N.Atkinson, Z.A.Khan and J.H.Whitelaw ,“Experimental investigation of opposed jets discharging normally into a cross-stream”, J.Fluid Mech.(1982), Vol.115,pp493-504,19825.J.D.Holdeman,R.Srinivasan,and A.Berenfeld,“Experiments in Dilution Jet Mixing”, AIAA Journal,Vol.21,No.10,pp.1436-1443, 1984.6.K.S.Chen and J.Y.Hwang,“Experimental Study on the Mixing of One-and Dual-Line Heated Jets with a Cold Crossflow in a Confined Channel”,Journal Vol.29,No.3,March 1991 7. 黃鎮江與鄭藏勝等人,“雷射全像干涉術應用於軸-側向進氣燃燒室混合效應之研究內之影響”,中國航空太空學會學 刊,pp.321-328,1985.8.邱耀平，“燃料噴射方式對後續燃燒過程特性研究”，能源季刊，pp.75-101，19969.Th. Doerr , M. Blomeyer and D.K. Hennecke ,“Optimization of Multiple Jets Mixing With a Confined Crossflow”,Journal of Engineering of Gas Turbines and Power , April 1997, Vol.119-315.10.Y.Kamotani,and I.Greber,“Experiments on a Turbulent Jet in a Cross Flow”, AIAA Journal, Vol.24, No.11, pp.1867-1869, 198611.R.K.Agarwal and W.W.Bower,“Navier-Stokes Computations of Turbulent Compressible Two-Dimensional Impinging Jet Flowfields”,AIAA Journal, Vol.20, No.5, pp.577-583, 1982.12. 王俊琪與李聰盛,“燃燒室內流體混和之研究” 中國航空太空學會年刊,pp.25-32,1985.13.J.M.M.Barata,D.F.G.Durao and M.V.Heitor,“Impingement of Single and Twin Turbulent Jets Through a Crossflow” AIAA Journal, Vol.29,No.4,pp.595-602,199114. 吳念祖,“駐焰器與側進冷卻突張式燃燒室漩渦流場效應分析”,逢甲大學機械工程研究所碩士論文(1990)15.Jorge M.M.Barata,“Fountain Flows Produced by Multiple Impinging Jets in a Crossflow”, AIAA Journal, Vol.34, No.12, December 1996, pp.2523-253016.張中明「具上限制版之紊流五噴射撞擊水平移動秤板流場數值模擬與分析(A Numerical Study of the Turbulent Flow Field from Confined Five Jets Impinge on a Horizontal Moving Plate)」第21屆全國力學會議(1997)17.許家隆「徹向噴流對後續燃燒器支流場混和效應數值模擬分析 (A Numerical Investigatio of Mixing of the Flow in a sequential Burner with Transverse Jets)」第24屆全國力學會議(2000)18.李耿昌「具限制版之紊流三維五噴射撞擊流場與熱傳數值模擬(A Numerical Study of Three Dimensional Turbulent Flow and Heat Transfer from Confined Five Impinging Slot Jets)」第24屆全國力學會議(2000)19.林忠明「多噴流對後續燃燒器混合之數值模擬分析」（A Numerical Study of Multiple Jets of Mixing in a Sequential Burner）第25屆全國力學會議(2001)20. Patankar S. V. and Spaiding D. B., “A Calculation Procedure for Heat, Mass and Momentum Transfer in Three-Dimensional Parabolic Flows”, INT. J. HEAT MASS TRANSFER, VOL. 15,pp.1787-1806.21. S.V. Patanker, “Numerical Heat Transfer and Fluid Flow”, Hemis--phere Publishing Corporation, New York, 198022. S.V. Patanker, “A Calculation Procedure for Two-Dimensional Elliptic Situations” ,Numerical Heat Tranfer,Vol.4,pp.409-425,198123. B. E. Launder and D.B. Spalding，“The Numerical computation of Turbulent Flow”comput. Method in Appl. Mech. and Engng. Vol.3, pp.269-289, (1974)