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題 名 | 煞車制動盤具多孔性散熱座之熱傳增益研究=Heat Transfer Enhancement of Porous Heat Sinks in the Braking Disk |
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作 者 | 鄭澤明; 曾憲中; 廖宏儒; | 書刊名 | 航空技術學院學報 |
卷 期 | 5:1 民95.08 |
頁 次 | 頁49-57 |
分類號 | 447.1185 |
關鍵詞 | 制動盤; 離心力; 柯氏力; 黏滯力; 多孔介質; Braking disk; Centrifugal; Coriolis; Viscous forces; Porous media; |
語 文 | 中文(Chinese) |
中文摘要 | 絕大部分的動力機械都以旋轉的方式達成動力的轉換。在車輛之制動盤方面,為提高煞車效率就必須提高制動盤和煞車碟片的摩擦力,但是相對的制動盤溫度提昇會形成煞車打滑咬死現像,所以制動盤必須加強本身的冷卻能力。在制動盤內部旋轉槽流冷卻問題由於離心力、柯氏力和黏滯力的強力交互作用,其流場特性更加複雜,在垂直旋轉流場加熱管道中,流場常因參數不同顯現單對渦流或多對渦流之定流或不定流之層紊流特性,因此也引起摩擦係數之增加,在熱傳係數也同時相對增加,除此之外,旋轉常會延緩層紊流過渡現象的發生,離心浮力會加強內流管道的熱傳效果,為使實驗條件儘量模擬實際車輛制動盤的運作範圍,除了將Pr、Re及幾何參數保持與實際情況一樣外, 並將多孔介質置入測試段槽道中,以增強流場紊流性和增加熱傳面積,進一步瞭解垂直旋轉加熱之多孔介質多管道之正壓面、負壓面及側面的局部熱傳係數,以提供車輛制動盤設計之參考。 |
英文摘要 | Most of power machinery achieves the energy conversion by rotation. In the braking of vehicles, to increase the braking efficiency, the friction force must be increased; the increased high temperature may cause the material degradation and therefore shortens the rotating disk life. Consequently, the cooling capacity of the disk should be enhanced. In the coolant problem of braking disk, due to the strong interaction among the centrifugal, Coriolis, and Viscous forces of the coolant air flow in rotating channels, the flow field become more complex than that for non-rotating ones. In a heated radially rotating channel, steady or unsteady, laminar or turbulent, one pair or multi-pairs of vortices may appear in the flow field depending on the flow and thermal parameters, therefore the friction factor and the Nusselt number may be increased simultaneously. Besides, rotation may delay the laminar-turbulent flow transition; the centrifugal buoyancy may enhance the heat transfer. To simulate the operation conditions in a real braking disk of vehicles, one must keep Pr, Re and geometric parameters approximately the same values as those in a real one. Besides, the open cell porous media material is embedding inside rotating channels to increase the heat transfer area. To understand further the local heat transfer characteristic on the pressure side, suction side and sidewalls for radially rotating channels. This study can be helpful in the related devices braking disk of of vehicles. |
本系統中英文摘要資訊取自各篇刊載內容。