买一套棋牌app需要多少 www.jbqtck.com.cn 譯文：本論文描述了發展的數值模擬繞流一個籠罩的螺旋錐齒輪的建模策略。策略，然后施加到一系列關鍵的護罩參數的參數變化。罩蓋和齒輪的問題是通用的，雖然根據所采用的羅爾斯·羅伊斯航空發動機內部的齒輪箱?；ふ殖萋值男枰醋哉庋氖率?，买一套棋牌app需要多少，旋轉時，像一個風扇的行為。工作是由齒輪移動周圍的流體，通常是空氣與油顆粒懸浮在里面，這創建了一個寄生損失，簡稱為風阻功率損耗。在本論文的工作是研究如何風阻功率損耗可以影響由齒輪和罩的幾何特征，一個更大的項目的一部分。大直徑（200毫米）齒錐齒輪運行在高轉速（> 10,000 RPM）的的風阻功率損耗形成的總功率損耗的主要部分，這是很重要的。
已經制定了這項工作的研究4種不同的流體流量設置：Taylor-Couette流，錐形Taylor-Couette流，無罩的螺旋錐齒輪，一個籠罩的螺旋錐齒輪的建模策略。 Taylor-Couette流的工作提供了基本的環境中試驗各種數值技術和增益熟悉的CFD的商業計劃，將用于整個論文（流利），隨著嚙合程序GAMBIT。它給了稱為錐形Taylor-Couette流的流量，然后將其用于模擬流Taylor-Couette流的變形例中，在氣缸與圓錐體所取代，理解。 4流行的湍流模型進行了比較，讓一個決定，’^好’的湍流模型使用在一個籠罩齒輪的建模，并開始發展的戰略。此策略，然后施加到更復雜的幾何形狀的一個開式齒輪，模擬實驗數據已經上創建了一個內部的鉆機。要確認籠罩螺旋錐齒輪建模的策略的適用性，它適用于兩個罩，實驗數據是可用的。結果表明，數值模擬，可以捕捉到相對性能護罩的。然后繼續考慮一系列的參數變化，即3個關鍵的壽衣參數是不同的3舉止，生產27變化的工作。這些參數可以影響風阻功耗：評估每個參數的影響的風阻功率損耗已被賦予多少。在’好’和’壞’的情況下的流場的描述，并通過近似使用可壓縮流的伯努利方程的形式，已經提出了一個’壞’的壽衣是’壞’的原因。原文：This thesis describes the development of a numerical modelling strategy for simulating the flow around a shrouded spiral bevel gear. The strategy is then applied to a series of parametric variations of key shroud parameters. The shroud and gear in question are generic, although based upon those employed in the internal gear box of a Rolls-Royce aeroengine. The need to shroud the gear comes from the fact that a spiral bevel gear, when rotated, acts like a fan. Work is done by the gear to move the surrounding fluid, usually air with oil particles suspended in it, which creates a parasitic loss, referred to as the windage power loss. The work within this thesis is part of a larger project which has investigated how windage power loss can be affected by geometric features of gears and shrouds. This is important as for large diameter (>200mm) bevel gears running at high speeds (>10,000 RPM) the windage power loss forms a substantial part of the total power loss.
The modelling strategy has been developed in this work by studying 4 different fluid flow settings: Taylor-Couette flow, Conical Taylor-Couette flow, an unshrouded spiral bevel gear, and a shrouded spiral bevel gear. Work on Taylor-Couette flow provided a basic setting in which to trial various numerical techniques and gain familiarity with the commercial CFD program which would be used throughout this thesis (FLUENT), along with the meshing program GAMBIT. It gave an understanding of the flow, which was then used to simulate the flow in a modification of Taylor-Couette flow where the cylinders are replaced with cones, called Conical Taylor-Couette flow. Comparisons were made between 4 popular turbulence models, allowing a decision to be made on the `best’ turbulence model to use in the modelling of a shrouded gear, and to start to develop the strategy. This strategy was then applied to the more complex geometry of an unshrouded gear, simulating experimental data which had been created on an in-house rig. To confirm the applicability of the strategy to modelling shrouded spiral bevel gears, it was applied to two shrouds for which experimental data was available. It showed that numerical modelling can capture the relative performance of the shrouds well. The work then continued by considering a series of parametric variations, whereby 3 key shroud parameters are each varied in 3 manners, producing 27 variations. Each of these parameters can affect the windage power loss: an assessment of how much each parameter affects windage power loss has been given. A description of the flow field in `good’ and `bad’ cases has been given, and through approximating the flow by using the compressible form of Bernoulli’s equation, reasons for a `bad’ shroud being `bad’ have been presented.