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    Please use this identifier to cite or link to this item: http://ccur.lib.ccu.edu.tw/handle/A095B0000Q/149

    Title: 高轉速氣動箔片軸承之箔片剛性設計;The design of foil stiffness of high speed rotation foil air bearing
    Authors: 陳仕皓;CHEN, SHIH-HAO
    Contributors: 機械工程系研究所
    Keywords: 箔片剛性;設計;Foil Stiffness;Design
    Date: 2018
    Issue Date: 2019-05-23 12:52:43 (UTC+8)
    Publisher: 機械工程系研究所
    Abstract: 微渦輪引擎中,通常使用球軸承或者氣體軸承作為潤滑系統,其應用包含渦輪機、無人飛機、偵蒐載具以及偏遠地區的發電設備,但在長時間以及高轉速的運轉需求下,以氣體軸承較具優勢。球軸承在使用上以滾動元件或液動壓作為潤滑,通常需要有效率的冷卻系統來維持液體潤滑的工作溫度,以確保潤滑系統正常的運作;而氣體軸承以氣體做為潤滑,其性能較不易受到溫度變化的影響。氣體軸承在潤滑系統中具有幾項符合長時間運轉需求的特性,如:無須定期保養、環境忍耐度高、操作溫度廣泛以及具有多種潤滑氣體可供選用,因此在高轉速長時間運轉、高溫操作環境及冷卻系統的考量下,選用箔片氣體軸承作為潤滑系統。 氣體軸承承受軸承負載能力低,因此需要加入彈簧箔片輔助氣膜支撐;利用箔片的變形以及可壓縮流的雷諾方程式作為研究方法,計算最小氣膜厚度與收斂壓力,輔助氣膜支撐軸承負載;其中箔片變形即是箔片剛性的呈現。本研究建立一模擬分析系統,研究工具包含電腦數值計算、箔片剛性量測設備以及Abaqus模擬軟體。研究中,從箔片的參數設計箔片剛性,改變箔片變形以產生足夠的氣膜使轉軸運轉順暢,並在不同軸承負載的需求下,對拱形箔片與片狀箔片做剛性的設計與分析。在研究結果中,利用電腦數值計算、箔片剛性量測設備與模擬軟體建立出箔片剛性設計系統,得出片狀箔片中以鉛直間距、間隙大小以及幾何高度,這三種設計參數能增加箔片剛性,其中以鉛直間距對於箔片剛性的影響最為靈敏;此外,為因應不同的軸承負載,提出大、中、小的軸承負載做拱型箔片與片狀箔片的剛性設計與分析,結果顯示拱型箔片適合用在大負荷,而片狀箔片適用在中、小負荷的情況。
    Foil gas bearing have wide industrial applications, mainly in micro-turbine engine and the aircraft industry else. Micro-turbine is the small size of gas turbine, and only equipped with single layer compressor and a turbine, which make the machine system having the advantage of small volume and suitable for high- speed rotating application. Turbine engine also have the need for long-time running lubrication system. Most important, air foil have remarkable potential for both aspect. This research project applies a lubrication system to meet the technology vision; developing a 80kg-thrust micro-turbine engine in the use of micro-turbine generator, small high-speed target drone, life propulsion system of standard high speed trap and long high speed rotating operations. In the application of high speed micro-turbine engine, the micro-turbine power system has the long running time requirements with the rotating speed up to 90,000 to 100,000 rpm and life needs ( for 30kW ) over 30,000 hours, so the primary is to choose a proper bearing lubrication system in the need of high speed and long time rotating. From the previous research, knowing spindle rotates in high speed and usually works in the environment of high temperature. Applying rolling or fluid hydrodynamic bearing, we need to use an efficient cooling system to make sure bearing working performance. Foil gas bearing isn’t vulnerable to temperature change, so we don’t need the cooling system in the allowable temperature range of foil material. Therefore we choose foil gas bearing, having high speed rotation and long-time operation, as the lubrication system and hope to enhance power efficiency and life-cycle of micro-turbine generator . We need lots of experience for the bearing design because it’s complicated to manufacture. For the purpose of making shaft lift, we set up a simulation and analysis system. Therefore, it’s needed to use related patent and article as reference and then take the calculation of experiment trend and result of simulation into account to analysis. After, provide the analysis result with reference data for research organization. While the design of the foil is the key aspect of affecting the performance of foil gas bearings, this research start with surface roughness of top foil and use the full-film hydrodynamic lubrication theory to calculate the minimum film thickness used for supporting shaft lifting. Try to reach the stiffness in the theory calculation with the calculation of programming language and design geometry foil for stiffness. Studying research analysis on present bump foil is also necessary. Eventually, hope to enhance the load capacity and reliability of foil gas bearing in real working.
    Appears in Collections:[機械工程學系] 學位論文

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