在高旋轉數下三角形內冷卻通道中交錯肋條排列形式之熱傳研究

Abstract

由於地球的資源有限，所以尋求在現有的能源使用效率上需有更好的發展。渦輪噴射系統，因使用於高空飛行載具上有迅速便利、良好的可靠度、以及較佳的推力重量比。因此，若能更進一步的提高燃氣渦輪機的效率，則可大幅的減輕能源供應上吃緊的情況。由前人的研究得知，與主流場方向行成45。攻角的交錯式肋條，在不同的通道截面寬高比與旋轉數下皆有較好的熱傳效果。因此本實驗所選定的紊流增強器幾何參數為45。交錯式肋條，實驗的排列形式共有四種，分別為45度肋條排列式、45度間斷式、45度V型、以及45度V型斷裂式，其中肋條高度-水力直徑比(e/Dh)為0.085、 肋條距離-高度比(P/e)為 9、雷諾數為15000至25000之間。若得知在高旋轉數下各作用力對熱傳增益的影響，對於燃氣渦輪機的冷卻設計上將更有實質上的貢獻。因此本實驗將以旋轉數約0~330 rpm下，研究各種肋條型式對冷卻通道內熱傳增益的影響。

Due to the limitation of earth’s resources, a better development for seeking efficient use of energy is needed. Gas turbine system for aircraft engines has the good reliability and the best power-to-weight ratio. Therefore, if we can advance the fuel efficiency, we may reduce the energy-supply distressed situation. From previous research, rib angle of attack of 45° has better heat transfer effects in various aspect-ratio channels with different rotation numbers. Therefore, this experiment will choose this rib angle. There are five rib arrangements: continuous ribs, discrete ribs, V-shaped ribs, and discrete-V shaped ribs. These rib configurations have the same rib height-to-hydraulic diameter ratio (e/Dh) of 0.085 and rib spacing to height ratio (P/e) of 9. Reynolds number is during 15,000~25,000. It is known that high-rotation number have influence on heat transfer, and it will be a great contribution in gas turbine's cooling techniques. Therefore, this experiment will study the influences of rib configuration on heat transfer in cooling passages and the rotating speed is set between 0~330 rpm.