請用此 Handle URI 來引用此文件：
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/93923完整後設資料紀錄
| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 王昭男 | zh_TW |
| dc.contributor.advisor | Chao-Nan Wang | en |
| dc.contributor.author | 方昕予 | zh_TW |
| dc.contributor.author | Hsin-Yu Fang | en |
| dc.date.accessioned | 2024-08-09T16:27:03Z | - |
| dc.date.available | 2024-08-10 | - |
| dc.date.copyright | 2024-08-09 | - |
| dc.date.issued | 2024 | - |
| dc.date.submitted | 2024-08-03 | - |
| dc.identifier.citation | [1] 黃家烈，《筆記型電腦散熱風扇之研究》，博士論文，國立臺灣科技大學機械工程系，2001。
[2] 李宗穎，《筆記型電腦散熱模組之數值與實驗整合研究》，碩士論文，國立臺灣科技大學機械工程系，2006。 [3] 劉宗明，《筆記型電腦散熱風扇最佳化設計》，碩士論文，國立屏東科技大學機械工程系，2011。 [4] 詹泓儒，《後傾式離心扇之流場模擬與性能改善》，碩士論文，國立臺灣科技大學機械工程系，2021。 [5] 詹仕弘，《抽油煙機性能之數值予實驗研究》，碩士論文，國立臺灣科技大學機械工程系，2009。 [6] 陳柏祥，《創新式舌部應用於燃氣爐具之離心風機的性能及噪音優化》，碩士論文，國立臺灣科技大學機械工程系，2022。 [7] 林筱增、周錫明、趙繼舜、潘冠呈、陳仁郁，〈風扇噪音頻譜特性量測與分析〉，中華民國振動與噪音工程學會論文集，pp. 142-149，2004年6月。 [8] 徐逸亭，《風扇噪音場分析模擬（與減噪設計）》，碩士論文，國立臺灣大學機械工程學研究所，2006。 [9] 吳御銓，《λ/4減噪器應用在離心扇之數值與實務整合研究》，碩士論文，國立臺灣科技大學機械工程系，2014。 [10] M. J. Lighthill, "On Sound Generated Aerodynamically. I. General Theory," Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 211, No. 1107, pp. 564-587, March 1952. [11] N. Curle, "The Influence of Solid Boundaries upon Aerodynamic Sound," Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 231, No. 1187, pp. 505-514, September 1955. [12] J.E. Ffowcs Williams and D.L. Hawkings, "Sound Generation by Turbulence and Surfaces in Arbitrary Motion", Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 264, No.1151, pp. 321-342, May 1969. [13] J. Smagorinsky, "General circulation experiments with the primitive equations," Monthly Weather Review, Vol. 91, No. 3, pp. 99-164, March 1963. [14] O. Reynolds, "On the Dynamical Theory of Incompressible Viscous Fluids and the Determination of the Criterion," Philosophical Transactions of the Royal Society of London A, Vol. 186, pp. 123-164, January 1895. [15] D. A. Morelli, R. D. Bowerman, "Pressure Distributions on the Blade of an Axial-Flow Propeller Pump. " Journal of Fluids Engineering, Vol. 75, No. 6, pp. 1007-1012, July 1953. [16] Bruno Eck, Fans; design and operation of centrifugal, axial-flow, and cross-flow fans. New Nork: Pergamon Press, 1973. [17] W. Neise, "Noise Reduction in Centrifugal Fans: A Literature Survey," Journal of Sound and Vibration, Vol. 45, No. 3, pp. 375-403, April 1976. [18] D. Raj, W. B. Swim, "Measurements of the Mean Flow Velocity and Velocity Fluctuations at the Exit of an FC Centrifugal Fan Rotor." Journal of Engineering for Gas Turbines and Power, Vol. 103, No. 2, pp. 393-399, April 1981. [19] A. Kjo ̈rk, L. Lo ̈fdahl, "Hot-Wire Measurements Inside a Centrifugal Fan Impeller. " Journal of Fluids Engineering, Vol. 111, No. 4, pp. 363-368, December 1989. [20] 鄭增堂，《離心式風機舌板改善性能測試研究》，碩士論文，國立台北科技大學能源與冷凍空調工程系，2011。 [21] 林宏鐘，《室內送風機氣動噪音之研究與改善》，碩士論文，國立臺灣師範大學機電工程系，2010。 [22] P. K. Kundu, Ira M. Cohen, and David R Dowling, Fluid Mechanics, 5th ed. Academic Press, 2011, ch. 12, pp. 545–549. [23] Y. Zhou, "Turbulence theories and statistical closure approaches," Physics Reports, Vol. 935, p. 9, November 2021 [24] AFS ENEA. (2009, January 23). ANSYS FLUENT 12.0 Theory Guide [Online] Available: https://www.afs.enea.it/project/neptunius/docs/fluent/html/th/main_pre.htm [25] P. Bradshaw, T. Cebeci, J. H. Whitelaw, Engineering Calculation Methods for Turbulent Flow, London: Academic Press, 1981. [26] W. P. Jones, B.E. Launder, "The prediction of laminarization with a two-equation model of turbulence," International Journal of Heat and Mass Transfer. Vol. 15, No.2, pp. 301-314, February 1972. [27] David C. Wilcox, "Formulation of the k-w Turbulence Model Revisited. " AIAA Journal, Vol. 46, No.11, pp. 2823-2838, November 2008. [28] D. You and P. Moin, "A dynamic global-coefficient subgrid-scale eddy-viscosity model for large-eddy simulation in complex geometries," Physics of Fluids, Vol. 19, No. 6, June 2007. [29] H. Nyquist, "Certain Topics in Telegraph Transmission Theory," Transactions of the American Institute of Electrical Engineers, Vol. 47, No. 2, pp. 617-644, April 1928. [30] C. E. Shannon, "A mathematical theory of communication," Bell System Technical Journal, Vol. 27, pp. 379-657, July and October 1948. [31] 王福軍, 《計算流體動力學分析-CFD軟件原理與應用》, 清華大學出版社, 2004。 | - |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/93923 | - |
| dc.description.abstract | 噪音是筆記型電腦使用者面臨的一大困擾，為了減少因空氣流動造成的氣動噪音，需先了解其成因及影響因素。本文主要以氣動聲學理論，使用計算流體力學進行數值模擬，了解改變風扇本身的幾何構造與額外增加結構對於風扇噪音頻譜與音量大小造成的改變。使用暫態大尺度渦流模擬法（LES）算出風扇流場，以此流場估算Ffowcs Williams and Hawkings（FW-H）聲學類比的聲音訊號。模擬結果顯示，縮減舌部間隙和優化流道結構皆能讓質量流率上升，提升風扇散熱效率，同時僅引起輕微的噪音增加。其中，縮減舌部間隙使質量流率上升4.95%，入口與出口聲音大小分別增加1.0 dB及1.5 dB；增加20毫米的流道結構可以提升5.01%的質量流率，入口聲音大小上升4.9 dB、出口降低聲音大小0.7 dB。本研究預期能為未來風扇降噪技術的開發提供指引，有助於減少筆記型電腦使用者所受的噪音困擾。 | zh_TW |
| dc.description.abstract | Fan noise is an inevitable annoyance for laptop users. Further investigation of causes and influencing factors is needed to reduce aeroacoustic noise from fans. Based on aeroacoustics and computational fluid dynamics (CFD), the study aims to examine resultant noise in different fan cases. This includes analyzing changes, in terms of its spectrum and the total sound pressure level, due to modifications in the fan’s structure and extra structures. Using the transient large eddy simulation (LES), we first obtain the detailed flow field. Next, the fan noise is computed from the flow field with the help of Ffowcs Williams and Hawkings (FW-H) acoustic analogy. Here we show that reducing the cut-off clearance and extending the flow discharge can increase the mass flow rate, enhancing the fan's cooling efficiency while only slightly increasing noise levels. Specifically, reducing the cut-off clearance increases the mass flow rate by 4.95%, with sound pressure levels at the inlet and outlet increasing by 1.0 dB and 1.5 dB, respectively. The 20 mm flow discharge extension increases the flow rate by 5.01%, with the inlet sound pressure level rising by 4.9 dB and the outlet sound pressure level reducing by 0.7 dB. We anticipate that our findings will serve as a guide for future research on fan noise reduction, potentially alleviating the noise-related discomfort experienced by laptop users. | en |
| dc.description.provenance | Submitted by admin ntu (admin@lib.ntu.edu.tw) on 2024-08-09T16:27:03Z No. of bitstreams: 0 | en |
| dc.description.provenance | Made available in DSpace on 2024-08-09T16:27:03Z (GMT). No. of bitstreams: 0 | en |
| dc.description.tableofcontents | 致 謝 i
摘 要 ii Abstract iii 目 次 iv 圖 次 vii 表 次 ix 第一章 緒論 1 1.1前言 1 1.2文獻回顧 2 1.2.1氣動聲學 2 1.2.2計算流體力學 3 1.2.3離心式風扇 3 1.3 論文架構 5 第二章 基本理論 6 2.1統御方程式（Governing Equation） 6 2.1.1連續方程式（Continuity Equation） 6 2.1.2動量方程式（Momentum Equation） 6 2.1.3能量方程式（Energy Equation） 7 2.2雷諾平均法（Reynolds-Averaged Navier-Stokes, RANS） 7 2.2.1k-ε紊流模型 10 2.2.2k-ω紊流模型 11 2.2.3SST k-ω紊流模型 12 2.3大尺度渦流模擬法（Large Eddy Simulations，LES） 14 2.4氣動聲學 15 2.4.1Lighthill聲學類比理論（Lighthill Acoustic Analogy） 15 2.4.2Ffowcs Williams and Hawkings方程式 16 2.4.3聲音大小之表示 19 第三章 數值模擬方法 20 3.1計算流程說明 20 3.2網格分布 21 3.3時間步長（Time Step Size）與時間步數（Number of Time Steps） 22 3.4邊界條件 23 3.4.1出入口邊界 23 3.4.2壁面邊界 23 3.4.3 連續邊界 23 3.5離散化求解 24 3.5.1求解器Solver 28 3.6網格獨立性劃分測試 29 第四章 暫態氣動噪音分析 32 4.1分析方法 32 4.2分析架構 32 4.3改變舌部間隙之影響 33 4.3.1增加舌部間隙 35 4.3.2縮減舌部間隙 40 4.4風扇出口加上流道之影響 42 4.5風扇流道加上整流板之影響 50 4.6綜合比較 55 第五章 結論與展望 56 5.1結論 56 5.2展望 57 參考文獻 58 | - |
| dc.language.iso | zh_TW | - |
| dc.title | 筆電散熱風扇氣動噪音之探討 | zh_TW |
| dc.title | A Study of the Aeroacoustic Noise of Laptop Fans | en |
| dc.type | Thesis | - |
| dc.date.schoolyear | 112-2 | - |
| dc.description.degree | 碩士 | - |
| dc.contributor.oralexamcommittee | 黃維信;謝傳璋;湯耀期 | zh_TW |
| dc.contributor.oralexamcommittee | Wei-Shien Hwang;Chuan-Cheung Tse;Yao-Chi Tang | en |
| dc.subject.keyword | 氣動聲學,離心式風扇,計算流體力學,大尺度渦流模擬法,FW-H聲學模型, | zh_TW |
| dc.subject.keyword | aeroacoustics,centrifugal fan,computational fluid dynamics,large eddy simulation (LES),Ffowcs Williams and Hawkings (FW-H) model, | en |
| dc.relation.page | 60 | - |
| dc.identifier.doi | 10.6342/NTU202403260 | - |
| dc.rights.note | 未授權 | - |
| dc.date.accepted | 2024-08-07 | - |
| dc.contributor.author-college | 工學院 | - |
| dc.contributor.author-dept | 工程科學及海洋工程學系 | - |
| 顯示於系所單位： | 工程科學及海洋工程學系 | |
文件中的檔案：
| 檔案 | 大小 | 格式 | |
|---|---|---|---|
| ntu-112-2.pdf 目前未授權公開取用 | 6.81 MB | Adobe PDF |
系統中的文件，除了特別指名其著作權條款之外，均受到著作權保護，並且保留所有的權利。