發動機排氣尾管紊流分佈與噪音抑制之數值研究

Numerical Study of Turbulent Distribution and Noise Suppression in the Gas Turbine Engine Exhaust Pipe

洪楚翔(Chu-Hsiang Hung)

指導教授 ： 吳文忠

國立虎尾科技大學/工程學院/飛機工程系航空與電子科技碩士班/碩士(2016年)

摘要

在機場環境的要求中，目前發動機噪音是影響環境的重要因素之一，降低噪音的設備是必須的。發動機主要噪音跟排出的高溫高速噴流與外部低速冷空氣混合的程度有關，要使噪音降低，必須改善內部流與外部空氣混合比例，故本文討論如何在排氣面積相同情況下改善外型，可以使其達到排氣風量不變而降低噪音的效果。
本研究採用CFD套裝軟體Fluent進行模擬，為了提高其準確性，首先進行模擬與實驗數據進行比較其聲壓水平，經過驗證之後以推力八千磅噴射引擎當作設計原型，並討論三種外型變化的影響，有Wave、Chevron及Fold型，減少排出的高速氣流與外部空氣劇烈衝擊以降低噪音，探討外型變化後尾段的氣流紊流狀況及噪音的分佈情形，以Chevron型尾管降噪效果最佳，降噪效果約為8-13dB。

關鍵字

發動機整流罩 ； 降低噪音 ； 外型變化 ； 波浪型 ； 尾管

並列摘要

In the requirements of the airport environment. At present the engine noise is one of the important factors affecting the environment, noise reduction equipment is necessary. The main noise of the engine is related to the degree of mixing of the discharged high-temperature high-speed jet with the external low-speed cold air. To reduce the noise, it is necessary to improve the mixing ratio of the internal flow and outside air. Therefore, this study discusses how to improve the appearance of the same exhaust area, which can achieve the same exhaust air volume and reduce the noise effect.
In this study, CFD software Fluent was used for simulation. In order to improve its accuracy. First, the simulated and experimental data were compared for their sound pressure levels. After validation, a thrust eight-thousand-pound jet engine was used as the prototype design. And discuss the influence of three kinds of appearance changes. Have Wave, Chevron and Fold types. To investigate the distribution of appearance change after the tail section of the air flow turbulence and noise situation. The Chevron - type tail pipe has the best noise reduction effect. Noise reduction effect is about 8-13dB.

並列關鍵字

nozzle ； Chevron ； noise ； subsonic ； suppression

參考文獻

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