Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/72181
標題: 橫向流與雙噴射流偶合流場之數值模擬與分析
Numerical+Simulation+of+An+Impinging+Twin-Jet+With+Cross+Flow
作者: 莊書豪
關鍵字: 偶合流場;數值模擬分析;橫向流;雙噴射流
出版社: 國立中興大學工學院;Airiti Press Inc.
Project: 興大工程學報, Volume 2, Page(s) 83-103.
摘要: 
The interest in jet and fan-powered vertical take off and landing (VTOL) military aircraft will increase in the near future. In this paper, a theoretical resarch to simulate theimpinging twin-jet with cross flow has been undertaken. Impinging twin-jet coupled withcross flow in closed ground effect have been modeled by using the compressible NavierStokes equations with a two-equation k-ε turbulence model.
The effects of cross flow onimpinging twin-jet are also investigated. Calculated results show that several recirculatingzones distribute around the flow field. The sizes and locations of them have close relationship with the jet exit height above ground, nozzle space and the strength of the cross flow.In the mean time, there was a fountain up-wash flow occurring between the nozzles andtwo low pressure recirculating zones were induced by the interaction between the nozzlemain stream and foruntain up-wash flow. The effects of the cross flow induces the suddendecrease in the lift force of the aircraft. The stronger the cross flow. the less the lift forceof the flow field.

本文研究的主要目的是以數值模擬的方法來分析具有上平板之二維平面雙噴射撞擊流流場。使用SIMPLE-C法則,利用連續方程式和非穩態動量方程式配合K-ε雙方程式紊流模式來計算壓力,速度,紊流動能,紊流動能消散率等值在流場之分析。並探究地表面和噴嘴間高度,噴嘴角度,噴嘴間距及橫向流對雙噴射撞擊流場的影響情形。
從數值計算所得的結果顯示流場會產生數個迴流區,其大小,位置與兩噴嘴高度,角度,間距及橫向流有密切關係。同時在噴嘴間會產生上沖噴泉氣流(Fountain up-wash flow)的現象,此氣流與噴嘴主流會誘導出兩個低壓迴流區,因而導致飛機升力損失。當兩噴嘴向內側對噴時,上沖噴泉氣流消失,導致流場的升力提高;而當兩噴嘴向外側對噴時,上沖噴泉氣流更加顯著,其與噴嘴主流誘導出之迴流區增大,因此流場升力下降。當兩噴嘴向內對噴時,噴嘴高度增加將導致流場升力下降。噴嘴間距加大,則流場升力增加。橫向流的影響將會造成升力驟減,其強度(即速度)愈大,流場升力愈小。
URI: http://hdl.handle.net/11455/72181
ISSN: 1017-4397
Appears in Collections:第02卷
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