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軸流風(fēng)機(jī)設(shè)計(jì)要素對(duì)性能影響的數(shù)值研究碩士學(xué)位論文(存儲(chǔ)版)

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【正文】 用已有的 CAD 軟件進(jìn)行工業(yè)造型無法滿足計(jì)算要求, 這樣本文采用商用 CFD 軟件進(jìn)行風(fēng)機(jī)的三維 數(shù)值 建模。 6. 葉片的成型 :葉片 各基元級(jí)確定后,需要將它們堆積起來組成一個(gè)葉片,這一過程稱為葉片的成型 [25]。 ; ? ?222222 uz CuCW ??? ( 214) 式中: 2W —— 出口相對(duì)速度, m/s; 2u —— 出口圓周速度, m/s。 在軸流風(fēng)機(jī)的設(shè)計(jì)中,軸流風(fēng)機(jī)是否加前后導(dǎo)葉要由 H 值來定,具體為:當(dāng)?H 時(shí),軸流風(fēng)機(jī)不加前后導(dǎo)葉;當(dāng) ~?H 時(shí),軸流風(fēng)機(jī)要加后導(dǎo)葉;當(dāng) ?H 時(shí),軸流風(fēng)機(jī)既要加前導(dǎo)葉也要加后導(dǎo)葉。 ( 1)流型 系數(shù)的選取 若軸流風(fēng)機(jī)采用合適的流型系數(shù)進(jìn)行設(shè)計(jì),那么其可以最大限度地利用電機(jī)輸入的功率,還可以將 電機(jī) 輸 入功率最大限度地轉(zhuǎn)化為軸流風(fēng)機(jī)的氣動(dòng)功,這樣也就使得軸流風(fēng)機(jī)的風(fēng)機(jī)出口動(dòng)能即式 ( 22) 減少到了最小。軸流風(fēng)機(jī)的動(dòng)葉通常從葉根到葉頂是扭曲狀的,其分為 機(jī)翼 型 和 圓弧板 型 等 。如圖 21 所示,軸 流風(fēng)機(jī)一般由整流罩、前導(dǎo)葉、葉輪、外筒和擴(kuò)散筒組成,其中葉輪和前導(dǎo)葉組成了該風(fēng)機(jī)的級(jí),下面詳細(xì)介紹軸流風(fēng)機(jī)每一個(gè)組成部件的作用。 最后 適當(dāng)調(diào)整 了 T35 軸流風(fēng)機(jī)的設(shè)計(jì)參數(shù), 經(jīng)過對(duì)比 將性能較好的 T35 軸流風(fēng)機(jī)作為新 T35 軸流風(fēng)機(jī) 的設(shè)計(jì)雛形。最后在 每個(gè)控制體上 將待解的控制方程做積分處理且 導(dǎo)出 對(duì)應(yīng)的離散方程,最后求解導(dǎo)出的離散方程,內(nèi)蒙古 工業(yè)大學(xué)碩士學(xué)位論文 6 這樣就 可以 得到了與實(shí)際物理模型相符合的解。為了與實(shí)際物理 問題相符 ,離散方程中的條件設(shè)置必須與實(shí)際物理?xiàng)l件相一致, 而且 離散方程需第一章 緒論 5 要給定求解控制參數(shù)進(jìn)行求解。 若 要建的幾何模型比較復(fù)雜,可以先用 CAD 和Solidworks 軟件 進(jìn)行建模,再將其導(dǎo)入 Gambit 軟件 中,最后利用 Fluent 軟件進(jìn)行 相應(yīng)的計(jì)算。而當(dāng)輪轂比為 時(shí),該風(fēng)機(jī)的效率會(huì)最低。 金元日 等人 [13]對(duì) 低壓軸流通風(fēng)機(jī) 分別采用自由渦設(shè)計(jì)和可控渦設(shè)計(jì)進(jìn)行整機(jī)數(shù)值建模,并且對(duì)采用可控渦設(shè)計(jì)的風(fēng)機(jī)進(jìn)行了性能預(yù)測分析。 SJ Seo 等人 [7][8]在低速軸流風(fēng)機(jī)的整機(jī)數(shù)值模擬中 采用了葉片非徑向堆積技術(shù),并且提出若該風(fēng)機(jī)同時(shí)采用葉片前傾和葉片前掠,那么此風(fēng)機(jī)的性能將得到很好地改善, 同時(shí)指出在 一個(gè)設(shè)計(jì)工況的全壓值下 該風(fēng)機(jī)的數(shù)值計(jì)算結(jié)果與實(shí)驗(yàn)相符合。 國內(nèi)外研究現(xiàn)狀 國外 研究現(xiàn)狀 Francois G. Louw 等 人 [4]討論了進(jìn)口無導(dǎo)葉軸流風(fēng)機(jī)的氣動(dòng)設(shè)計(jì), 同時(shí) 指出不同 流型系數(shù) 具有不同的氣動(dòng)設(shè)計(jì), 而且 合適的可控渦設(shè)計(jì)要比自由渦設(shè)計(jì)復(fù)雜的多。軸流通風(fēng)機(jī)的傳統(tǒng)設(shè)計(jì)方法的特點(diǎn)是簡單、應(yīng)用方便且設(shè)計(jì)周期短,至今仍然是風(fēng)機(jī)行業(yè)的主流設(shè)計(jì)方法。 眾所周知, 隨著我國重工業(yè)的不斷發(fā)展,煤炭量的消耗也隨之增加,而其中有一大部分煤炭是被風(fēng)機(jī)消耗的 [1]。在此基礎(chǔ)上本文通過對(duì)新 T35軸流風(fēng)機(jī)的三維數(shù)值模擬,研究了該風(fēng)機(jī)的輪轂比、流型系數(shù)、葉片前傾和葉片前掠等設(shè)計(jì)要素對(duì)其性能的影響。隨著我國面臨越來越大的環(huán)境治理和節(jié)能減排壓力,研制開發(fā)和使用高效風(fēng)機(jī)產(chǎn)品將是通風(fēng)機(jī)行業(yè)重點(diǎn)關(guān)注的領(lǐng)域。 ( 分類號(hào) : 學(xué)校代碼 : U D C : 學(xué) 號(hào) : 碩士學(xué)位論文 類 別:全日制碩士研究生 題 目:軸流風(fēng)機(jī)設(shè)計(jì)要素對(duì)性能影響的數(shù)值研究 英文題目: The Numerical Research on Performance Effect for Design Elements of Axial Flow Fans 學(xué)科名稱:熱能與動(dòng)力工程 二○一四年 四 月 原 創(chuàng) 性 聲 明 本人聲明:所呈交的學(xué)位論文是本人在導(dǎo)師的指導(dǎo)下進(jìn)行的研究工作及取得的研究成果。 (請?jiān)谝陨戏娇騼?nèi)打“ √ ”) 學(xué)位論文作者簽名: 指導(dǎo)教師簽名: 日 期: 日 期: 內(nèi) 蒙古工業(yè)大學(xué)碩士學(xué)位論文 摘 要 軸流風(fēng)機(jī)在工業(yè)和生活中的應(yīng)用極為廣泛, 同時(shí) 也消耗大量能源。改進(jìn)后的程序不僅具有 了 高效靈活的特點(diǎn),而且其可以很好的與后續(xù)的數(shù)值模擬進(jìn)行銜接。 關(guān)鍵詞 : 軸流風(fēng)機(jī) ; 設(shè)計(jì)要素 ; 數(shù)值模擬;性能 影響 內(nèi) 蒙古工業(yè)大學(xué)碩士學(xué)位論文 Abstract Axial flow fans have extensive application in industry and life, they also consume abundant energy. As our country is under increasing pressure of environmental governance, energy conservation and emission reduction, fan industry focus on the fields which are researching, developing and using highefficiency fan products. The T35 axial flow fan is a kind of ventilation product used for many years in our country, its application range also is very wide, but the existing T35 fan efficiency is still not high. Based on the current situation of inefficient T35 axial flow fan, this article developed the new T35 axial flow fan by using engineering design experience and modern design methods and studied the performance effect of several important design elements for it. Firstly, this article introduced engineering method of axial flow fan pneumatic design especially including vane design, then described the whole machine threedimensional flow field numerical simulation method in conducting fan aerodynamic performance simulation, including numerical modeling, meshing, boundary conditions, convergence criterion and so on, and further discussed the performance calculation results difference of the fan under different numerical modeling, different fan outlet static pressure postprocessing and different boundary condition settings. The numerical simulation results can be pared with the measured results by adopting the appropriate modeling and numerical simulation postprocessing. The whole machine numerical simulation grids of the fan is obtained by grid tests, so it is of important foundation for subsequent discussing performance effect of the T35 axial fan’s design elements. Secondly, the article got a new T35 axial flow fan design prototype on the basis of the existing T35 axial flow fan, meanwhile improved input format, output format and partial experience parameter settings for the existing pneumatic design procedure. The improved procedure not only has the characteristics of highefficiency and flexibility, and it can primely link up subsequent numerical simulation. On the basis through conducting threedimensional numerical simulation of the new T35 axial flow fan, this article studied fan performance effect because of the fan’s design elements such as hub ratio, flow coefficient, forward lean, forward swept and so on. Finally, through the above research, the conclusions are: Firstly, fan pressure increases 內(nèi) 蒙古工業(yè)大學(xué)碩士學(xué)位論文 slightly at first and then decreases with the increase of hub ratio, fan efficiency gradually decreases by and large with the increase of hub ratio. Secondly, fan pressure increases at first and then decreases and increases at last with the increase of flow coefficient, fan efficiency increases at first and then decreases with the increase of flow coefficient. Thirdly, fan pressure and fan efficiency decreases with the increase of forward lean angle. Finally, fan pressure decreases slightly at first and then increases and decreases at last with the increase of forward swept angle, fan efficiency volatility decreases with the increase of forward swept angle. Through the analysis of the above design factors, the conclusions are: the T35 axial flow fan’s best design is that hub ration should be , flow coefficient should be , forward Lean blade is not suitable for it, forward swept blade is suitable for it. The performance of the T35 axial flow fan in the design scheme is better than the old T35 axial flow fan, the results show that total pressure is increased by and total pressure efficiency is increased by %. Key words: Axial flow fan; design elements; Numerical simulation; performance effect 內(nèi) 蒙古工業(yè)大學(xué)碩士學(xué)位論文 目
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