臺灣博碩士論文加值系統

本文目的在探討空氣在低雷諾數 紊流模式下，在平行粗糙渠道間之流場、溫度場及微粒附著沉積之應用。並利用計算流體力學套裝軟體PHOENICS來作數值模擬。在渠道間以二維穩定流場狀態來考慮，粗糙度是以凸出方塊來表示。制御方程式之建立包括連續、動量、能量及濃度方程式。在流場探討迴流區大小與粗糙高度和渠道寬度之比值(h/D)有關，另外也探討凸塊高度與摩擦因子之關係。溫度場則以固定熱通量為邊界條件。濃度場則以無因次微粒鬆弛時間與無因次沉降速度來探討。粗糙度的影響包括流場、溫度場及濃度場。主要結果如下：(1)凸塊後面迴流區域約為粗糙高度6倍，但與節距和凸塊高度之比值(p/h)無關，所以凸塊越大迴流區域越大。(2)凸塊越大壓力降越大，所以摩擦因子越大。(3)渠道溫度隨著粗糙凸塊高度增加而增加，而雷諾數越大溫度越小。(4)無因次微粒沉積速度隨著凸塊節距增加而減少。(5)在相同節距時，凸塊高度越大無因次微粒沉積速度越小。

The purpose of this study is to determine the air flow field, temperature field, and the particles deposition with the low Reynolds number turbulent flowing in a channel with roughness ribs. The PHOENICS CFD software package is used for calculation the physical model. The channel is decided in steady flow of two dimensions; by the way, the roughness also is decided on overhang of rib. The govern equations are include to continue equation, momentum equation, energy equation and concentration equation. In the flow field, the major objective is studying the recirculation region within channel and roughness height of ribs that they do have relate with ration (h/D) of channel width, In addition, it also study about relation between ribs height and friction factor. The temperature field is defined fix heat flux for boundary conditions, beside, the concentration filed is studying between relax time of deposition of non-dimensional particles and velocity of deposition of non-dimension. Roughness affected the flow field, temperature field and concentration field. The major results are follow as：(1) Recirculation region is about six times of roughness height after ribs, but the pitch is not relax with ratio (p/h) of ribs height, so, the bigger ribs, the larger recirculation region. (2) The bigger ribs, the larger the pressure drop and friction factor. (3) The channel temperature is increased with rib height, but the bigger Reynolds numbers, the smaller the temperature. (4) If the rib pitch is increase, the velocity of deposition of non-dimensional particles is lower. (5) As the same pitch, the higher rib, the smaller the velocity of deposition of non-dimensional particles.

中文摘要 i
ABSTRACT ii
目錄 iv
圖表目錄 vi
符號說明 ix
第一章 導論與文獻回顧 1
1-1 前言 1
1-2 問題描述 2
1-3 文獻回顧 4
第二章 統御方程式 8
2-1統御方程式 9
2-2 修正後之低雷諾數 模式 10
2-3 邊界條件 13
2-4摩擦因子、摩擦速度和微粒沉降速度之計算 14
第三章 數值方法 19
3-1 PHOENICS的結構 19
3-2 PHOENICS的應用 21
3-3 鬆弛係數 24
3-4 收斂標準 26
3-5 PHOENICS的源項(Source term) 26
3-6 資料輸入檔介紹 27
第四章 結果與討論 33
4-1 流場 33
4-2 溫度場 35
4-3 濃度場 35
第五章 結論與未來展望 64
5-1 結論 62
5-2 未來展望 62
參考文獻 64

【1】C. Yap, “Turbulent Heat and Momentum Transfer in Recirculating and Impinging Fliw, “Ph. D. Dissertation, U. of Manchester, UK, 1987.【2】PHOENICS(Parabolic Hyperbolic or Elliptic Numerical Integration Code Series), Available from CHAM Ltd., 40 High St., Wimbledom, London, SW19 5AU, England.【3】D. B. Spalding, ‘Recent Advances in Numerical Methods in Fluids,’ Ed. C. Taylor and K. Morgan, pp. 139-167, 1980.【4】S. ACHARYA, T. MYRUM, X. QIU, and S. SINHA, Int. J. Heat Mass Transfer, 40, pp. 461-479, 1997.【5】B. H. Chang, “Computation of Turbulent Recirculating Flow in Channels and for Impingment Cooling,” Ph, D. Dissertation, UCLA, 1992.【6】B. K. LEE., N. H. CHO and Y. D. CHOI, Int. J. Heat Mass Transfer, 31, pp. 1797-1805, 1988.【7】K. W. Lee J. A. Gieseke and M. A. Goldenberg, NUREG/CR-1264, BMI-2041, 1979.【8】K. W. Lee and J. A. Gieseke, J. Aerosol Sci., 25, pp. 699-709, 1994.【9】A. Li and G. Ahmadi, Aerosol Sci. Technol., 18, pp. 11-24, 1993.【10】A. Li, G. Ahmadi, R. G. Bayer and M. A. Gaynes, Aerosol Sci. 25, pp. 91-112, 1994.【11】L. J. Forney and L. A. Spielman, J. Aerosol Sci., 5, pp. 257-271, 1974.【12】B.E. Launder, and D. B. Spalding, Mathematical models of turbulence, Academic Press, London and New York, 1972.【13】S. K. Friedlander,“Smoke, dust and Haze ”Wiley-interscience, New York, 1977.【14】S. V. Patanka, “Numerical Heat Transfer and Fluid Flow,” Hermisphere publish Corp. NY, 1980.【15】M. Dalle Donne and L. Meyer, “Turbulent Convection Heat Transfer from Rough Surfaces with Two Dimensional Rectangular Ribs,” Int. J. Heat Mass Transfer, Vol. 20, pp. 583-620, 1977.【16】鄭永昌, “低雷諾數 紊流模式在平行粗糙板渠道間流場之應用分析,” 中原大學機械研究所碩士論文, 1997.【17】Webb, R. L., Eckert, E. R.. G., and Goldstein, R.. J., “Heat transfer and friction in tubes with repeated-reb roughness”, Int. J. Heat Mass Transfer, vol 14, pp. 601-617, 1971.