抽油煙機之流場模擬與氣動噪音分析

Abstract

本研究主要在於探討抽油煙機之流場與氣動噪音，在數值計算上使用有限體積法與LES紊流模式計算抽油煙機之流場，利用Ffows Williams-Hawkings聲場方程式計算其氣動噪音。針對抽油煙機之流場與聲場作分析，利用計算結果求出抽油煙機噪音源產生的位置。 綜合模擬結果與分析，抽油煙機的聲場能量分佈與流場中壓力擾動有關，具有較高聲場能量分佈的區域，乃是噪音源產生的位置。從聲壓位準圖中，可以得知抽油煙機的氣動噪音是由窄頻噪音與寬頻噪音所組成。其最高峰值頻率大約為 5800Hz，處於人耳的敏感範圍內，因此抽油煙機所產生的噪音會對人們造成一定程度的影響。

The major purpose of this paper is to study the flow field and acoustic noise of a range hood by numerical methods. In the numerical calculation, a finite volume method and LES turbulent model are adopted to solve the flow. For acoustic noise analysis, Ffowcs-Williams and Hawkings formulation is used to predict the sound pressure level of the range hood. The results show that the acoustic noise level is related with the pressure fluctuation of the flow. The acoustic noise of range hood is composed of narrow-band noise and broad-band noise. It is dominant at 5800Hz which is in the sensitive area of human hearing. Therefore, the reduction of the range hood noise is essential.