本文選題：風力機噪聲 + 半經(jīng)驗公式��； 參考：《中國科學院研究生院(工程熱物理研究所)》2014年博士論文

【摘要】：隨著風電行業(yè)的快速發(fā)展,風電機組的單機容量越來越大,葉片長度也越來越長,輻射噪聲水平也隨之快速增加。已有研究和分析表明,現(xiàn)代大型風電機組的主要輻射噪聲來源于葉片的氣動噪聲,并且氣動噪聲水平近似和葉尖速度的5次冪成正比關系。風電葉片長度的增加使得葉片柔性增大,產生氣動彈性問題,從而誘發(fā)額外的輻射噪聲。為了滿足環(huán)境噪聲標準的要求,風力機的設計轉速需要控制在一定范圍內,致使在額定風速下,風能利用系數(shù)遠離設計最優(yōu)值,如果能降低葉片的氣動噪聲使得風力機的限制轉速提高,額定風速相應降低,風能就可以得到更充分的利用,同時提高轉速還可以降低作用在軸上的扭矩,減少機組的主軸、齒輪箱、發(fā)電機等部件的載荷,增強結構安全可靠性。另外,在葉片設計過程中,通過低噪聲葉片設計提高風力機的限制轉速,從而將最優(yōu)風能利用系數(shù)對應的尖速比進一步提高,可以降低葉片的實度,減少葉片的重量并降低成本。作者利用BPM翼型自身噪聲半經(jīng)驗公式和Amiet來流湍流半經(jīng)驗公式預測研究了某2.5MW風力機(GW109/2500)的輻射噪聲,噪聲預測結果和現(xiàn)場實驗結果吻合較好。來流風速對輻射噪聲的影響研究結果表明,風力機輻射噪聲主要受轉速影響,來流風速變化對噪聲的影響較小,同理來流風剪切對輻射噪聲的影響也較小。另外,研究表明,葉片輻射噪聲最大的位置位于葉片展向的80-95%,對于地面某一觀察點而言,葉片處于某—特定位置的時刻輻射噪聲最大,這些結論都和現(xiàn)場實驗測量結果—致。作者對中國科學院工程熱物理研究所研發(fā)設計的大厚度、鈍尾緣翼型的輻射噪聲進行了研究,發(fā)現(xiàn)來流風速較小時,翼型分離失速噪聲占主導,而當來流風速較大時,鈍尾緣脫落渦噪聲超過分離失速噪聲成為主要聲源。另外,為了深入分析研究由于葉片的非定常運動引發(fā)的氣動噪聲問題,作者建立了運動翼型的噪聲預測模型,并進行了數(shù)值驗證。推導了二維FW-H方程的頻域運動單極子聲源公式用于運動翼型的輻射噪聲計算,結果表明,由于翼型的非定常運動引起的單極子聲源強度大于由于翼型表面非定常載荷引起的偶極子聲源強度。隨后對運動翼型的非定常流場和聲場進行了研究。對于定常入流速度下的浮沉和俯仰運動的翼型,隨著翼型運動頻率的增大,升阻力系數(shù)幅值增大,遠場輻射噪聲也隨之增強。對于湍流來流情況,當翼型浮沉頻率較小時,湍流來流使得升阻力系數(shù)較定常來流時增大；當翼型浮沉頻率增大到0.5Hz時,湍流來流并沒有使升阻力系數(shù)增大,而是和定常來流結果很相近,作者認為這可能是由于尾渦結構發(fā)生改變,導致渦結構對流場的影響超過湍流來流的作用。對于湍流來流下的俯仰運動翼型,可以得到類似結論。
[Abstract]:With the rapid development of wind power industry, the single unit capacity of wind turbine becomes larger and larger, the length of blade becomes longer and longer, and the level of radiation noise increases rapidly. It has been studied and analyzed that the main radiated noise of modern large-scale wind turbine is from the aerodynamic noise of blade, and the level of aerodynamic noise is proportional to the fifth power of blade tip velocity. With the increase of blade length, the blade flexibility increases, resulting in Aeroelastic problem, which induces additional radiation noise. In order to meet the requirements of environmental noise standards, the design speed of wind turbine needs to be controlled within a certain range, so that under rated wind speed, the wind energy utilization coefficient is far from the optimum design value. If the limited speed of the wind turbine can be increased by reducing the aerodynamic noise of the blade, and the rated wind speed is reduced accordingly, the wind energy can be utilized more fully, and at the same time, the torque acting on the shaft and the main shaft of the unit can be reduced by increasing the speed. Gear box, generator and other parts of the load, enhance structural safety and reliability. In addition, in the process of blade design, the limited speed of wind turbine can be increased through the design of low noise blade, so that the tip speed ratio corresponding to the optimal wind energy utilization coefficient can be further increased, and the real degree of blade can be reduced. Reduce blade weight and cost. By using the semi-empirical formula of self-noise of Amiet airfoil and the semi-empirical formula of Amiet turbulent flow, the authors have studied the radiated noise of a 2.5MW wind turbine GW 109 / 2500). The results of noise prediction are in good agreement with the field experiment results. The results show that the radiation noise of wind turbine is mainly affected by the rotational speed, the change of the incoming wind speed has little effect on the noise, and the influence of the shear of the incoming wind on the radiation noise is also small. In addition, it is shown that the position of the maximum radiation noise of the blade lies in the 80-95b of the blade span. For a certain observation point on the ground, the time when the blade is at a certain position is the most radiated noise. These conclusions are all due to the results of the field experiments. The authors have studied the large thickness and the radiation noise of the blunt tail flange airfoil developed and designed by the Institute of Engineering Thermal Physics of the Chinese Academy of Sciences. It is found that the airfoil separation stall noise is dominant when the incoming wind speed is small, but when the incoming flow velocity is large, the airfoil separation stall noise is dominant. The obtuse edge shedding vortex noise is more than the separated stall noise as the main sound source. In addition, in order to analyze the aerodynamic noise caused by the unsteady motion of the blade in depth, the noise prediction model of the moving airfoil is established and verified numerically. In this paper, the frequency domain monopole sound source formula of two dimensional FW-H equation is derived to calculate the radiated noise of moving airfoil. The results show that, The intensity of monopole source caused by unsteady motion of airfoil is larger than that of dipole source caused by unsteady load on airfoil surface. Then the unsteady flow field and sound field of the moving airfoil are studied. For the airfoil with steady inflow velocity, the amplitude of the lift resistance coefficient increases with the increase of the motion frequency of the airfoil, and the far field radiation noise is also enhanced with the increase of the motion frequency of the airfoil. In the case of turbulent flow, when the floatation frequency of airfoil is small, the coefficient of lift resistance increases when the frequency of airfoil is small, and when the frequency of floating and sinking of airfoil increases to 0.5 Hz, the coefficient of rising resistance is not increased when the frequency of airfoil is increased to 0.5 Hz. The results are very close to those of the steady flow. The authors think that this may be due to the change of the wake vortex structure, which results in the effect of the vortex structure on the flow field exceeding the effect of the turbulent flow. A similar conclusion can be obtained for the pitching airfoil under turbulent flow.
【學位授予單位】：中國科學院研究生院(工程熱物理研究所)
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM315

【引證文獻】

相關期刊論文 前1條

1 程君妮;;模擬戶外風速裝置設計[J];自動化儀表;2017年05期

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本文編號：2032534