| 研究生: |
余宗樺 Yu, Tzung-Hua |
|---|---|
| 論文名稱: |
具有各種隔板之封閉倉儲的三維自然對流熱傳特性研究 Study on the Heat Transfer Characteristics of 3D Natural Convection in Enclosed Storage with Various Partitions |
| 指導教授: |
陳寒濤
Chen, Han-Taw |
| 學位類別: |
碩士 Master |
| 系所名稱: |
工學院 - 機械工程學系 Department of Mechanical Engineering |
| 論文出版年: | 2021 |
| 畢業學年度: | 109 |
| 語文別: | 中文 |
| 論文頁數: | 131 |
| 中文關鍵詞: | 自然對流 、建築散熱 、計算流體力學 、逆算法 |
| 外文關鍵詞: | natural convection, building heat dissipation, computational fluid dynamics, inverse algorithm |
| 相關次數: | 點閱:178 下載:0 |
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鐵皮屋因建築成本低且工序簡單,因此常被各行業作為倉儲使用。當夏天時,因為氣溫急速升高,使得鐵皮屋內室溫上升,對於一些囤放電子設備之倉儲來說,大多需要利用通風口、風扇甚至是加裝冷氣進行室內散熱,進而增加電費、設備維修等費用。因此本文架設一簡易封閉式倉儲,透過最小平方法求得空腔外部之未知熱源,由模擬軟體ANSYS Icepak所計算之結果挑選最適合之流動模型,並透過溫度及流場分布圖與實驗進行比對,探討倉儲在不同擺設配置及太陽日照方位之情況下,於封閉式空腔之熱傳與流場流動。
結果顯示,在本研究所使用之RANS中,Transition SST模型與實驗量測點之結果最為接近。在頂部及任一短邊壁面作為加熱面時,在短邊壁面上有加裝隔板之影響最大,會使室內空氣溫度提高,其效應隨著短邊加熱面距離逐漸減小;在頂部及任一長邊壁面作為加熱面時,當長邊隔板中間增加間隔,空氣利於上下層空氣對流混合,且流速上升,使整體空氣溫度較為平均,減少上層熱空氣聚熱,對流效應提高。而在增加長邊隔板寬度之情況下,雖可增強隔板與周圍空氣之對流效應,但障礙物面積增加,使上層空氣不易與下層空氣進行混合。
Because of the low construction cost and simple process, iron house is often used as storage in various industries. In summer, because of the rapid rise in temperature, the room temperature of the iron room rises. For some electronic equipment storage, most need to use vents, fans or even add air conditioners for indoor heat dissipation, thus increasing the cost of electricity, equipment maintenance and other costs. Therefore, this paper sets up a simple closed storage, and obtains the unknown heat source outside the cavity by using the least square method. The most suitable flow model is selected by the results calculated by simulation software ANSYS Icepak, and the temperature and flow field distribution map are compared with the experiment to explore the storage under different equipment configurations and solar sunlight orientation. Heat transfer and flow field flow in a closed cavity.
The results show that the Transition SST model is the closest to the experimental measurements of the RANS used in this study. When the top and any short side wall are used as the heating surface, the effect of installing a partition on the short side wall is the greatest, which will increase the indoor air temperature. The effect decreases with the distance of the short side heating surface. When the top and any long side wall surface are used as the heating surface, when the interval between the long side partition is increased, the air is conducive to the convection mixing of the upper and lower air, and the flow rate rises, so that the overall air temperature is more average, the heat accumulation of the upper hot air is reduced, and the convection effect is improved. When the width of the long partition is increased, the convection effect between the partition and the surrounding air is enhanced, but the area of the barrier is increased, which makes it difficult for the upper air to mix with the lower air.
[1] L. L. Wang and W. Li, A study of thermal destratification for large warehouse energy savings, Energy Build., vol. 153, pp.126-135, 2017.
[2] I. V. Miroshnichenko, M. A. Sheremet, and A. A. Mohamad, Numerical simulation of a conjugate turbulent natural convection combined with surface thermal radiation in an enclosure with a heat source, Int. J. Therm. Sci., vol. 109, pp. 172-181, 2016.
[3] M.A. Almeshaal, K. Kalidasan, F. Askri, R. Velkennedy, A.S. Alsagri and L. Kolsi, Three-dimensional analysis on natural convection inside a T-shaped cavity with water-based CNT–aluminum oxide hybrid nanofluid, Int. J. Therm. Anal. Calorim., vol. 139, pp. 2089-2098, 2020.
[4] A. Raji, M. Hasnaoui, M. Firdaouss and C. Ouardi, Natural convect-ion heat transfer enhancement in a square cavity periodically
cooled from above, Numer. Heat Transf. Appl., vol. 63, pp. 511-533, 2013.
[5] G. Yu, Z. Lian, W. Gan and J. Ji, Numerical investigation on the effect of harmonic horizontal-axis rotation on laminar natural convection in an air-filled enclosure. Int. J. Heat Mass Transf., vol. 152, 2020.
[6] M. Arici, H. Karabay and M. Kan, Flow and heat transfer in double, triple and quadruple pane windows, Energy Build, vol. 86, pp. 394-402, 2015.
[7] M. Arıcı, Ç. Yıldız, S. Nižetić, A. Shahsavar and A. Campo,
Implications of boundary conditions on natural convective heat transfer of molten phase change material inside enclosures, Int. J. Energy Res., vol. 45, pp7631-7650,2020.
[8] K. C. Jhang and W. J. Wu, Simulation of the natural convection under the condition near critical Ra number (weakly turbulence).
[9] W. Y. Su, Study of 3D CFD Inverse Method on Natural Convection Heat Transfer in Rectangular Cavity, 2021.
[10] T. Fusegi, J. M. Hyun, K. Uwahara and B. Farouk, A numerical study of three dimensional in a differentially heated cubical enclosure, Int. J. Heat Mass Transf., vol. 34, pp.1543-1557, 1991.
[11] T. Basak, S. Roy, S. K. Babu and A. R. Balakrishnana, Finite element analysis of natural convection flow in a isosceles triangular enclosure due to uniform and non-uniform heating at the side walls, Int. J. Heat Mass Transf., vol. 51, pp. 4496-4505,2008.
[12] Ç. Yıldız, a. E. Yıldız, M. Arıcı, N. A. Azmi, A. Shahsavarc, Influence of dome shape on flow structure, natural convection and entropy generation in enclosures at different inclinations: A comparative study, Int. J. Mech. Sci., vol. 197, 2021.
[13] G. Yesiloz and O. Aydin, Laminar natural convection in right-angled triangular enclosures heated and cooled on adjacent walls, Int. J. Heat Mass Transf., vol. 60, pp.365-374, 2013.
[14] M. Y. Ha and M. J. Jung, A numerical study on three-dimensional conjugate heat transfer of natural convection and conduction in a differentially heated cubic enclosure with a heat-generating cubic conducting body, Int. J. Heat Mass Transf., vol. 43, pp. 4229-4248, 2000.
[15] M. N. A. Saïd, R. A. MacDonald and G. C. Durrant, Measurement of thermal stratification in large single-cell buildings, Energy Build., vol. 24, pp.105-115, 1996.
[16] W. A. Kouz, A. Alshare, S. Kiwan, A. A. Muhtady, A. Alkhalidi and A. H. Saadeh, Two-dimensional analysis of low-pressure flows in an inclined square cavity with two fins attached to the hot wall, Int. J. Therm. Sci., vol. 126, pp. 181-193, 2018.
[17] A.K. Sharma, K. Velusamy and C. Balaji, Interaction of turbulent natural convection and surface thermal radiation in inclined square enclosures, Heat Mass Tran., vol. 44, pp-1153-1170, 2008.
[18] D. K. Singh and S.N. Singh, Conjugate free convection with surface radiation in open top cavity, Int. J. Heat Mass Transf. vol. 89, pp. 444-453, 2015.
[19] H. Hassan and N.Y. Abdel Shafey, 3D study of convection-radiation heat transfer of electronic chip inside enclosure cooled by heat sink, Int. J. Therm. Sci., vol. 159, 2021.
[20] N. Kasagi, Y. Tomita and A. Kuroda, Direct Numerical Simulation of Passive Scalar Field in a Turbulent Channel Flow, J. Heat Transfer, vol. 114, pp. 598-606.
[21] W. Guo and H. M. Prasser, Mixed convection study on the influence of low Prandtl numbers and buoyancy in turbulent heat transfer using DNS, Ann. Nucl. Energy, vol. 158, 2021.
[22] D. Kizildag, F. X. Trias, I. Rodríguez and A. Oliva, Large eddy and direct numerical simulations of a turbulent water-filled differentially heated cavity of aspect ratio 5, Int. J. Heat Mass Transf., vol. 77, pp. 1084-1094, 2014.
[23] Q. Chen and J. V. D. Kooi, A methodology for indoor airflow computations and energy analysis for a displacement ventilation system, Energy Build., vol. 14, pp.259-271, 1990.
[24] Q. Chen and W. Xu, A zero-equation turbulence model for indoor airflow simulation, Energy Build., vol. 28, pp.137-144, 1998.
[25] V. Yakhot and S. A. Orszag, Development of turbulence models for shear flows by a double expansion technique, Phys. Fluids, vol. 4, 1992.
[26] B.E. Yuce and E. Pulat, Forced, natural and mixed convection benchmark studies for indoor thermal environments, Int. Commun. Heat Mass Tran., vol. 92, pp.1-14, 2018.
[27] Z. J. Zhai, Z. Zhang, W. Zhang and Q. Y. Chen, Evaluation of various turbulence models in predicting airflow and turbulence in enclosed environments by CFD: part 1 – summary of prevalent turbulence models, HVAC&R Research, vol. 13, pp. 853-870, 2007.
[28] Validation of a zero-equation turbulence model for complex indoor airflows, Build. Eng., vol. 105, pp.414-427.
[29] A. Moser , List of annex-documentation: Annex 20: air flow patterns within buildings, I. E. A., p.77, 1995.
[30] X. Chai, W. Li, B. Chen, X. Liu, J. Xiong and X. Cheng, Numerical simulation of turbulent natural convection in an enclosure with a curved surface heated from below, Prog. Nucl. Energy, vol. 126, 2020.
[31] B. E. Launder and B. I. Sharma, Application of the energy-dissipation model of turbulence to the calculation of flow near a spinning disc, Lett. Heat Mass Tran., vol. 1, pp. 131-137, 1974.
[32] D. Kizildag, F. X. Trias, I. Rodríguez, A. Oliva, Large eddy and direct numerical simulations of a turbulent water-filled differentially heated cavity of aspect ratio 5, Int. J. Heat Mass Transf., vol. 77, pp. 1084-1094, 2014.
[33] T. Wu and C. Lei, On numerical modelling of conjugate turbulent natural convection and radiation in a differentially heated cavity, Int. J. Heat Mass Transf., vol. 91, pp.454-466, 2015.
[34] J. Salat, S. Xin, P. Joubert, A. Sergent, F. Penot and P. Le Quéré, Experimental and numerical investigation of turbulent natural convection in a large air-filled cavity, Int. J. Heat Fluid Flow, vol. 25, pp. 824-832, 2004.
[35] S. Xin, J. Salat, P. Joubert, A. Sergent, F. Penot and P. Le Quéré, Resolving the stratification discrepancy of turbulent natural convection in differentially heated air-filled cavities. Part III: a full convection–conduction–surface radiation coupling, Int. J. Heat Fluid Flow, vol. 42, pp.33-48, 2013.
[36] A. Sergent, S. Xin, P. Joubert, P. Le Quéré, J. Salat and F. Penot, Resolving the stratification discrepancy of turbulent natural convection in differentially heated air-filled cavities – Part I: reference solutions using Chebyshev spectral methods, Int. J. Heat Fluid Flow, vol. 39, pp. 1-14, 2013.
[37] H. T. Chen, J. P. Song, and Y. T. Wang, Prediction of heat transfer coefficient on the fin inside one-tube plate finned-tube heat exchangers, Int. J. Heat Mass Transfer, vol. 48(13), pp. 2697-2707, 2005.
[38] H. T. Chen and W. L. Hsu, Estimation of heat transfer coefficient on the fin of annular-finned tube heat exchangers in natural convection for various fin spacings, Int. J. Heat Mass Transfer, vol. 50(9), pp. 1750-1761, 2007.
[39] H.-T. Chen, M.-C. Lin, and J.-R. Chang, Numerical and experimental studies of natural convection in a heated cavity with a horizontal fin on a hot sidewall, Int. J. Heat Mass Transfer, vol. 124, pp. 1217-1229, 2018.
[40] H. T. Chen, W. X. Ma, and P. Y. Lin, Natural convection of plate finned tube heat exchangers with two horizontal tubes in a chimney: Experimental and numerical study, Int. J. Heat Mass Transfer, vol. 147, p. 118948, 2020.
[41] Q. Chen and W. Xu, A zero-equation turbulence model for indoor airflow simulation, Energy and Build., vol. 28, pp. 137-144, 1998.
[42] B. E. Launder and D. B. Spalding, "The numerical computation of turbulent flows," in Numerical Prediction of Flow, Heat Transfer, Turbulence and Combustion: Elsevier, pp. 96-116, 1983.
[43] V. Yakhot, S. A. Orszag, S. Thangam, T. B. Gatski and C. G. Speziale, Development of turbulence models for shear flows by a double expansion technique, Physics of Fluids A, vol. 4, pp. 1510-1520, 1992.
[44] F. R. Menter, R. B. Langtry, S. R. Likki, Y. B. Suzen, P. G. Huang, and S. Volker. A Correlation Based, Transition Model Using Local Variables Part 1 - Model Formulation, 2004.