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題名 | 噴嘴暫態流場起始過程之數值研究=Numerical Study of the Starting Process in a Reflected Nozzle for Transient Flow |
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作者 | 苗志銘; 戴昌賢; 李峻溪; | 書刊名 | 中正嶺學報 |
卷期 | 30:1 2001.10[民90.10] |
頁次 | 頁67-79 |
分類號 | 447.5533 |
關鍵詞 | 起始過程; 震波反射; 三叉點; 馬赫幹; Starting process; Shock reflection; Triple point; Mach stem; |
語文 | 中文(Chinese) |
中文摘要 | 本文的重點是以數值,模擬二維噴嘴在不同入口形狀下之起始過程,統御方程式為三維依時性那維爾-史托克方程式,數值方法為有限體積法、算則採用顯式上風法及TVD法。研究參數含括二種不同噴嘴入口形狀(圓弧、尖端)以及二種不同噴嘴角度(10"、15")。本研究之模擬結果在定性與定量的分析方面與實驗數據及可視流場圖騰均相當吻合。此外,本研究亦清楚地捕捉出當主震波剛進入噴嘴時的流場演進過程,可視化結果明顯地呈現因震波反射作用所產生之複雜暫態流場特徵,包括馬赫反射所產生之反射震波、三叉點、馬赫幹等等;不同外形噴嘴所產生的震波反射現象並不相同,進而造成往後流場現象的差異。比較10°與15°噴嘴,發現在噴嘴前緣之反射域,其流場特徵相符,不受角度改變之影響,噴嘴角度較小者,二次震波愈早離開噴嘴,使起始過程較早結束,而達到穩態,但噴嘴角度較大者,其加速效果較佳,能達到較高之馬赫數。 |
英文摘要 | The aim of present study is using CFD technique to simulate the starting process of the two-dimensional reflection nozzles. The governing equations are full Navier-Stokes equation. The numerical code is developed based on the finite volume method coupled with the upwind Roe's scheme and TVD method. Besides the inlet geometry, the effect of the deflection angle on the flow structure is also considered. The numerical results show a good agreement with the experimental data in the qualitative and quantitative analysis. Numerical results indicated that after the shock enters the nozzle inlet, the shock reflection results in a complicated transient flow features including Mach reflection, tripe point and Mach stem, etc. Due to the shock reflection dominate the development of the flow structure, different nozzle inlet results in an obviously discrepancy in flow characteristics, especially on the entrance region of angle. For the half nozzle angle effect, the flow features belong to case of nozzle angle 10° and 15° are almost identical in reflection region. To reach the steady state quickly, the smaller half nozzle of 10° is a better choice in present study. However, the test case of bigger half nozzle angle 15° exhibits a well accelerative ability in reflection nozzle. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。