臺灣博碩士論文加值系統

本文主要目的為用數值方法計算跳躍式壁溫水平圓管的熱流現象，在入口時流場為完全發展層流，管前半端為低溫區，經過跳躍點後進入高溫，並討論結合自然對流及熱輻射效應時對管內熱流場的影響。吾人用SIMPLER 來解統御方程式。
吾人以三種模式來處理熱輻射源項，其中考慮氣體之間及管壁對氣體的熱輻射效應為完整熱輻射模式，假設薄光學厚度則只考慮管壁對氣體的熱輻射效應，只考慮管壁徑向的熱輻射效應為徑向熱輻射模式 。我們選擇用來測試的氣體為水蒸氣及一氧化碳，此兩種氣體在高溫時輻射效應不可忽視。
我們發現自然對流效應會造成圓管內包括溫度及速度的劇烈變動，破壞其對稱性，而熱輻射效應則使得流場溫度快速且均勻的上升，同時減低自然對流效應的強度。

The study for laminar mixed convection combined with radiation in the thermal entrance region of pipe flow is important in any industrial applications requiring the prediction of short-tube heat transfer performance.
This thesis presents an analytical procedure for simultaneous convective and radiative heat transfer with a fully developed laminar flow in a pipe. The fluid is treated as a gray,absobing and emitting medium.
Three radiation models have been used to investigate the radiative transfer.The complete radiation model,not only the emission and absorption between thegas and the tube wall.The optically thin radiation model neglects the radiative heat exchanges among gas.In the other radial radiation model,the radiative intensities are regarded as a constant intensity with a wall.
When fluids are heated or cooled in horizontal tubes, the resulting temperature difference gives rise to density variation.So, the naturnal convective heat transfer is also important in pipe flow.

第一章 導論
1.1 引言 1
1.2 文獻回顧 2
1.3 本文概述 3
第二章 數學與物理模式
2.1 統御方程式 4
2.2 氣體熱性質 6
2.3 熱輻射性 7
2.4 熱輻射模式 8
2.5 邊界條件 10
第三章 數值方法
3.1 SIMPLE程式 11
3.2 管中心邊界數值上的處理 14
3.3 熱輻射源項數值上的計算 15
第四章 結果與討論
4.1 不同熱輻射模式的探討 16
4.2 入口Re的影響 18
4.3 不同氣體的比較 20
4.4 Ra的影響 20
4.5 光學厚度的影響 21
第五章 結論 22
參考文獻 23

[1]L. Graetz, ``Uber die Warmeleitungsfahigheit von Flussigkeiten,'' Part 1, Ann. Phys. Chem., Vol. 18, pp. 79-94; 1883, Part 2, Ann. Phys. Chem.,Vol. 25, pp. 337-357, 1885.
[2] R. K. Shah and A. L. London, `` Laminar flow forced convection in ducts,'' Advances in Heat Transfer, Academic Press, New York, 1978.
[3] A. Akyurtlu, J. F. Akyurtlu, K. S. Denison and C.E. Hamrin,
``Application of the General Purpose Collocation software, Pdecol,To the Graetz Problem,'' Computers & Chemical Engineering, Vol. 10, No. 3, pp. 213-222, 1986.
[4] R. F. Barron, Xianming Wang, T. A. Ameel and R. O. Warrington, ``The Graetz Problem Extended to Slip-flow,''
, Vol. 40. No8. pp. 1817-1823, 1997.
[5]M. L. Michelsen and J. Villadsen, ``The Graetz Problem with
Axial Heat conduction,'', Vol. 17, pp. 1391-1402, 1974.
[6]S. Bilir, ``Numerical Solution of Graetz Problem with
Axial Conduction,'' Numerical Heat Transfer, Part A,Vol. 21, pp. 493-500, 1992.
[7]J. Ou and K. C. Cheng, ``Natural Convection Effects on
Graetz Problem in Horizontal Isothermal Tubes,'' , Vol.20, pp. 953-960, 1977.
[8]M. Hishida, Y. Nagano and M. S. Montesclaros,``Combined Forced and Free Convection in the Entrance Region of an
Isothermally Heated Horizontal Pipe,'' ASME Journal of Heat
Transfer, Vol. 104, pp. 153-159, 1982.
[9]F. C. Chou and G. J. Hwang, ``Numerical Analysis of the Graetz Problem with Natural Convection in a Uniformly Heated Horizontal Tube,'', Vol. 31, No. 6, pp.1299-1308, 1988.
[10]C. Gau and D. C. Chi, ``A Simple Numerical Study of Combined Radiation and Convection Heat Transfer in the Entry Region of a Circular Pipe Flow,'' in Proceedings of the Second ASME/JSME Conference, Vol. 3, pp. 635-643, 1987.
[11] G. Yang and M. A. Ebadian, ``Thermal Radiation and Laminar Forced Convection in the Entrance Region of a Pipe with Axial Conduction and Radiation,'' , Vol. 12, No. 3, pp. 202-209, 1991.
[12]J. M. Huang and J. D. Lin, ``Combined Radiation and Natural Convection Effects on Graetz Problem in Horizontal Isothermal Circular Tubes,'' , Vol. 27, pp. 457-463, 1992.
[13]W. M. Kays and M. E. Crawford, Convective Heat and Mass Transfer,3rd Edition, McGraw-Hill, New York, 1993.
[14]M. N. Ozisik, Radiative Transfer and Interaction with Conduction and Convection}, John Wiley & Sons, New York, 1973.
M. N. Ozisik, Radiative Transfer and Interactions with Conduction and Convection, John Wiley & Sons, New York, 1973.
[15]M. F. Modest, Radiative Heat Transfer, McGraw-Hill, New York, 1993.
[16]R. Echigo, S. Hasegawa and K. Kamiuto, ``Composite Heat Transfer in a Pipe with Thermal Radiation of Two-Dimensional
Propagation - in Convection with the Temperature Rise in Flowing Medium Upstream from Heating Section,'' , Vol. 18, pp. 1149-1159, 1975.
[17]L. P. Paz, Cipolla, J. W., Jr. and T. F. Morse, ``The Effects of Radiation on Particle Deposition in MCVD: The Optically Thin Case,'' National Heat Transfer Conference, Heat Transfer Phenomena in Radiation, Combustion, and Fires, HTD-vol. 106, pp. 157-163, 1989.
[18]T. Hayase, J. A. C. Humphrey and R. Greif, ``A Consistently Formulated QUICK Scheme for Fast and Stable Convergence Using Finite-Volume Iterative Calculation Procedures,'' Journal of Computational Physics, Vol. 98, pp. 108-118, 1992.
[19]S.~V.~Patankar,Numerical Heat Transfer and Fluid Flow,
Hemisphere, Washington, D. C., 1980.
[20]B. P. Leonard, ``A Stable and Accurate Convective Modeling Procedure Based on Quardratic Upstream Interpolation,'' Computer Methods in Applied Mechanics and Engineering,
Vol. 19, pp. 59-98, 1979.
[21]F. H. Harlow and J. E. Welsh, ``Numerical Calculation of Time Dependent Viscous Incompressible Flow of Fluid with a Free Surface,'' Physics of Fluid, Vol. 8, pp. 2182-2189, 1965.