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研究生: 徐震驊
Hsu, Chen-Hua
論文名稱: 應用具狹縫斜肋之平板於方形通道加熱塊之紊流強制對流熱傳增益研究
Study on Heat Transfer Enhancement for Turbulent Forced Convection over Heated Blocks in a Square Channel by a Plate with Slits and Inclined Ribs
指導教授: 吳鴻文
Wu, Horng-Wen
學位類別: 碩士
Master
系所名稱: 工學院 - 系統及船舶機電工程學系
Department of Systems and Naval Mechatronic Engineering
論文出版年: 2019
畢業學年度: 107
語文別: 英文
論文頁數: 127
中文關鍵詞: 具斜肋與狹縫的平板強制紊流對流熱傳增益加熱塊方形通道
外文關鍵詞: Plate with slit and inclined ribs, forced turbulent convection, heat transfer enhancement, heated blocks, square channel
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  • 本文係利用有限體積法(FVM)離散Navier-Stokes方程式和能量方程式並化成代數方程組。接著運用解壓力耦合方程一致的半隱式方法(SIMPLE, Semi-Implicit Method for Pressure-Linked Equation Consistent) 迭代至收斂,獲得流場及溫度場。此模擬將三種不同斜肋間距比(為斜肋間距對風道高度比的簡稱)的鰭片: 斜肋間距比= 1.2、0.8和0.6,放置於33 mm x 33 mm x 750 mm通道內,固定放置高度(22mm)改變離入口的放置位置(230, 250 and 270 mm)和雷諾數(5000, 6500, 8000, 9500),分析強制對流之溫度場與速度場分佈。
    研究結果顯示:在雷諾數等於5000-9500,熱塊前端(0.3L)斜肋間距比= 0.6(C7)的平均紐賽數較其他兩種提高,最大增加率為7.2%。在雷諾數等於5000-9500,熱塊中段(0.33L)斜肋間距比= 0.8(C5)的平均紐賽數較其他兩種提高,最大增加率為6.0%。在雷諾數等於5000-9500,熱塊後段(0.36L)斜肋間距比= 0.6(C9)的平均紐賽數較其他兩種提高,最大增加率為10.3%,可以得知縮短間距有助於熱傳增益。從鰭片之平均紐賽數上看到,在雷諾數等於5000-9500,C2、C5和C8相較於其他擺放位置鰭片的平均紐賽數是最高的。在三種不同數量的斜肋間距比與三種不同的位置,在熱塊的中段,熱傳效益是最好的,熱性能係數隨雷諾數增加而下降,隨著鰭片移動到熱塊的中段(0.36L),熱性能係數效益最佳,在C7得到最佳的熱性能係數。

    The Navier-Stokes equations and energy equation are constructed by the Finite Volume Method (FVM) and then are discretized to a system of algebraic equations and dimensionless of mathematical formulation. They can be solved by semi-implicit method for pressure linked equations-consistent (SIMPLE). The solutions must be iterated to converge within each step to obtain the temperature and flow field.
    This simulation places three different plate with slits and inclined ribs (pitch ratio= 1.2, 0.8 and 0.6) on a channel (33 mm x33 mm x750 mm) and changes the x direction (230, 250 and 270 mm) with four Re levels (5000, 6500, 8000, 9500) to investigate the temperature and flow field without gravity in forced convection.
    In this study, the pitch ratio and the placed position of the plate with slits and inclined ribs are changed to study the effect of the influence on the heat transfer. At Re= 5000-9500, the (Nu)avg of pitch ratio= 0.6 (C7) in the front section of the heated blocks (0.3L) is improved compared with the other two cases (C1 and C4), and the maximum increase rate is 7.2%. At Re= 5000-9500, the (Nu) avg of pitch ratio= 0.8 (C5) in the middle section of the heated blocks (0.33L) is improved compared with the other two cases (C2 and C8), and the maximum increase rate is 6.0%. At Re= 5000-9500, pitch ratio= 0.6 (C9) in the rear section of the heated blocks (0.36L) is improved compared with the other two cases (C3 and C6), and the maximum increase rate is 10.3%, and it can be known that decreasing the pitch ratio contributes to the heat transfer. At Re= 5000-9500, the (Nu)avg of C2, C5 and C8 are higher than those of other placed positions. For three different pitch ratio and different placed positions, heat transfer benefit is best in middle section of the heated blocks, and the (Nu)avg of C5 is highest. The thermal performance factor decreases when the Re increases. When the plate with slits and inclined ribs is moved to the middle of the heated blocks, thermal performance factor increases the most. At Re= 5000-9500, thermal performance factor of C7 is highest.

    摘要 I 誌謝 II Abstract III Content V List of Table VII List of Figure VIII Nomenclature XIX Chapter 1 Introduction 1 1-1 Background 1 1-2 Literature reviews 3 1-3 Objectives and motivation of present study 10 Chapter 2. Numerical theory and geometry 12 2-1 Principle 12 2-2 Mathematical formulation 12 2-2-1 Parameters 13 2-3 Renormalized Group (RNG) turbulence model 15 2-4 Discretization method 17 2-4-1 Finite volume method 17 2-4-2 Least Squares Cell Based 18 2-4-3 Discretization of momentum equation 19 2-4-4 Discretization of energy equation 20 2-5 SIMPLE method 20 2-5-1 Velocity-correction equation 20 2-5-2 Computational process 22 2-5-3 Under-relaxation factor 22 2-6 Geometry model and mesh 23 2-6-1 Numerical model 23 2-6-2 Geometry 23 2-6-3 Mesh 24 2-7 Boundary conditions and Parameters 25 2-7-1 Boundary conditions 25 2-7-2 Convergence criterion 25 Chapter 3 Results and discussion 26 3-1 Grid and time-step independent test 26 3-2 Accuracy of simulation 27 3-3 Influence of different pitch ratio to flow field and heat transfer performance 27 3-4 Influence of plate with slits and inclined ribs on different placement of X direction to flow field and heat transfer performance 30 Chapter 4 Conclusions and future work 33 4-1 Conclusion 33 4-2 Future work 34 References 35

    [1] S. A. EI-Sayed, S. A. EI-Sayed, M. E. AbdelHamid and M. M. Sadoun,“Experimental study of turbulent flow inside a circular tube with longitudinal interrupted fins in the streamwise direction”, International Journal of Heat and Mass Transfer, Vol.15, pp.1-15, 1997.
    [2] X. F. Peng, G. G. Peterson and B. X. Wang, “Frictional flow characteristics of water flowing through rectangular microchannels”, Experimental Heat Transfer, Vol.7, pp.249-264, 1994.
    [3] P. -S. Lee and S. V. Garimella and D. Liu, “Investigation of heat transfer in rectangular microchannels”, International Journal of Heat and Mass Transfer, Vol.48, pp.1688-1704, 2005.
    [4] Wang, Yabo, Zhu, Kai, Xui, Zhou, Wei and Jie, “Effects of the location of the inlet and outlet on heat transfer performance in pin fin CPU heat sink”, Applied Thermal Engineering, Vol.151, pp.506-513,2019.
    [5] P. Naphon and S. Klangchart, “Effects of outlet port positions on the jet impingement heat transfer characteristics in the mini-fin heat sink”, International Communications in Heat and Mass Transfer, Vol.38, pp.1400-1405, 2011.
    [6] Y. Yoon, S. -J. Park, D. R. Kim and K. -S. Lee, “Thermal performance improvement based on the partial heating position of a heat sink”, International Journal of Heat and Mass Transfer, Vol.124, pp.752-760, 2018.
    [7] H. -Y Li, S.-M. Chao and G. -L. Tsai, “Thermal performance measurement of heat sinks with confined impinging jet by infrared thermography”, International Journal of Heat and Mass Transfer, Vol.48, pp.5386-5394, 2005.
    [8] D. Jang, S. -J Yook and K. -S. Lee, “Optimum design of a radial heat sink with a fin-height profile for high-power LED lighting applications”, Applied Energy, Vol.116, pp.260-268, 2014.
    [9] I. Elbadawy, A. Sabry, M. H. Shedidb and A. Basheer, “Heat transfer characteristics in wake region of a single finned obstacle”, International Journal of Thermal Sciences, Vol.128, pp.149-159, 2018.
    [10] F. Bentarzi, A. Mataoui and M. Rebay, “Effect of inclination of twin impinging turbulent jets on flow and heat transfer characteristics”, International Journal of Thermal Sciences, Vol.137, pp.490-499, 2019.
    [11] A. Boonloi and W. Jedsadaratanachai, “Turbulent forced convection in a heat exchanger square channel with wavy-ribs vortex generator”, Chinese Journal of Chemical Engineering, Vol.23, pp.1256-1265, 2015.
    [12] M. Fiebig, P. Kaiiweit, N. K. Mitra and S. Tiggelbeck,“Heat transfer enhancement and drag by longitudinal vortex generators in channel flow”, Experimental Thermal and Fluid Science, Vol.4, pp.103-114, 1991.
    [13] J. -S Leu, Y. -H Wu and H. -Y Jang, “Heat transfer and fluid flow analysis in plate-fin and tube heat exchangers with a pair of block shape vortex generators”, International Journal of Heat and Mass Transfer, Vol.47, pp.4327-4338, 2004.
    [14] H. Huisseune, C. T'Joen, P. De Jaegar, B.Ameel, S. De Schampheleire and M. De Paep, “Performance enhancement of a louvered fin heat exchanger by using delta winglet vortex generators”, International Journal of Heat and Mass Transfer, Vol.56, pp.475-487, 2013.
    [15] H. Tan, L. W. Wu, M. Y. Wang, Z. H. Yang and P. G. Du, “Heat transfer improvement in microchannel heat sink by topology design and optimization for high heat flux chip cooling”, International Journal of Heat and Mass Transfer, Vol.129, pp.681-689, 2019.
    [16] M. H. Min, C. Y. Qi, X. F. Kong and J. F. Dong, “Experimental study of rectangular channel with modified rectangular longitudinal vortex generators”, International Journal of Heat and Mass Transfer, Vol.53, pp.3023-3029, 2010.
    [17] S. W. Perng, H. W. Wu and T. C. Jue, “Numerical investigation of heat transfer enhancement on a porous vortex-generator applied to a block- heated channel”, International Journal of Heat and Mass Transfer, Vol.55, pp.3121-3137, 2012.
    [18] Q. W. Wang, Q. Y. Chen, L. Wang, M. Zeng, Y. P. Huang and Z. J. Xiao, “Experimental study of heat transfer enhancement in narrow rectangular channel with longitudinal vortex generators”, Nuclear Engineering and Design, Vol.237, pp.686-693, 2007.
    [19] P. C. Huang, Y. J. Chen and M. C. Tzou, “Pulsating convective cooling across two porous-covering heated blocks”, International Journal of Heat and Mass Transfer, Vol.52, pp.932-951, 2009.
    [20] S. Y. Kim, B. H. Kang and J. M. Hyun, “Forced convection heat transfer from two heated blocks in pulsating channel flow”, International Journal of Heat and Mass Transfer, Vol.41, pp.625-634, 1998.
    [21] F. Selimefendigil and H. F. Oztap, “Numerical study and identification of cooling of heated blocks in pulsating channel flow with a rotating cylinder”, International Journal of Thermal Sciences, Vol.79, pp.132-145, 2014.
    [22] H. F. Oztop, Y. Varol and D. E. Alnak, “Control of heat transfer and fluid flow using a triangular bar in heated blocks located in a channel”, International Communications in Heat and Mass Transfer, Vol.36, pp878-885, 2009.
    [23] A. W. Islam, M. A. R. Sharif and E. S. Carlson, “Mixed convection in a lid driven square cavity with an isothermally heated square blockage inside”, International Journal of Heat and Mass Transfer, Vol.55, pp.5244-5255, 2012.
    [24] D. Lorenzini-Gutierrez, A. Hernandez-Guerrero, J. L. Luviano-Ortiz and J. C. Leno-Conejo, “Numerical and experimental analysis of heat transfer enhancement in a grooved channel with curved flow deflectors”, Applied Thermal Engineering, Vol.75, pp.800-808, 2015.
    [25] C. Herman and E. Kang, “Comparative evaluation of three heat transfer enhancement strategies in a grooved channel”, Heat and Mass Transfer, Vol.37, pp.563-575, 2001.
    [26] J. -K. Wu, “Study on Heat transfer enhancement for laminar forced convection over heat sources in a channel by a narrow plate with slits and inclined ribs”, Thesis of Department of Systems and Naval Mechatronic Engineering, National Cheng Kung University, 2018.
    [27] S.V. Patankar, “Numerical Heat Transfer and Fluid Flow”, McGraw-Hill, New York, 1980.
    [28] A. Bejan, “Convection heat transfer”, John Wiley and Sons Inc., New York, 1985.
    [29] F. P. Incropera and D.P. Dewitt, “Fundamentals of heat transfer and mass transfer”, John Wiley and Sons Inc., New York, 2011.
    [30] S. A. Beig, E. Mirzakhalili and F. Kowsari, “Investigation of optimal position of a vortex generator in a blocked channel for heat transfer enhancement of electronic chips”, International Journal of Heat and Mass Transfer, Vol.54, pp.4317-4324, 2011.

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