冷却用弯掠轴流风机变型设计及气动噪声分析

发布时间：2018-04-11 06:17

本文选题：弯掠轴流风机 + 变型设计　；参考：《华中科技大学》2011年硕士论文

【摘要】：轴流风机广泛地应用于各个行业并起着核心的作用，高效率、低噪声的轴流风机已有一些成熟的模型，但是每种型号的风机都有其特定的最佳工况，当被用于其他场合时就会出现规格或性能不匹配的问题。基于弯掠轴流风机的优越性，本文将弯掠轴流风机应用于变压器冷却的高温环境中，并提出了一种变型设计的方法解决性能不匹配的问题。获得已有弯掠轴流风机的结构尺寸及试验数据，确定旋转区域、进口风道、出口风道等计算区域，，建立计算模型并进行网格划分，选择合适的计算方法，对弯掠轴流风机模型进行了定常数值模拟并预测其外部性能。将预测及试验得到的风机全压-流量性能曲线在同一坐标系中进行比较，验证所选的数值模拟方法的正确性。为满足给定的流量和全压要求，利用变型设计方法得到了弯掠轴流风机的五种结构方案A/B/C/D/E，采用同样的计算方法预测它们的全压-流量及全压效率-流量性能曲线，筛选出了满足流量和全压要求且效率较高的B/E风机。对五种风机的叶轮轴向和径向特征流面上的全压和速度流线分布特性进行了分析，进一步验证了所筛选风机的优越性。E风机叶轮加工完成后在进口试验台进行了性能试验，验证筛选出的风机可以满足流量及全压要求。以稳态流场为基础，采用大涡模拟（LES）结合Lighthill声类比的改进方程——FW-H声学模型的方法对筛选出的B/E风机进行非定常计算及气动噪声预测。比较了远场噪声测点D处声压级的预测值及试验值。分析了以叶轮表面作为噪声源时B/E风机的涡流噪声频谱特性，研究了风机三维非定常内部流场中旋涡分布特性，并探讨了风机旋转区域内部声压级的分布规律，证明E风机满足给定的噪声要求。进一步探讨了E风机在不同转速时旋转区域内部不同位置气动噪声的时域和频域特性。最后结合本文工作的总结及不足之处，提出了对弯掠轴流风机气动噪声进行深入研究的方向。
[Abstract]:Axial flow fans are widely used in various industries and play a core role. High efficiency, low noise axial flow fans have some mature models, but each type of fan has its own specific optimal conditions.Specifications or performance mismatches occur when used in other situations.Based on the superiority of the bending-swept axial fan, this paper applies the bending-swept axial fan to the high temperature environment of transformer cooling, and puts forward a variant design method to solve the problem of performance mismatch.The structural dimensions and experimental data of the existing bending-swept axial fan are obtained, and the calculation areas such as rotation area, inlet air passage and outlet duct are determined, and the calculation model is established and meshed, and the appropriate calculation method is selected.The steady numerical simulation and the prediction of the external performance of the bending-swept axial fan model are carried out.The predicted and tested total pressure-flow performance curves of the fan are compared in the same coordinate system to verify the correctness of the numerical simulation method.In order to meet the requirements of given flow rate and total pressure, the five structural schemes A / B / C / D / E of the bending-swept axial flow fan are obtained by using the modified design method, and their total pressure-flow and total pressure-efficiency / flow performance curves are predicted by the same calculation method.The B / E fan with high efficiency is selected to meet the demand of flow and pressure.The distribution characteristics of total pressure and velocity streamline on the axial and radial characteristic flow surfaces of the impeller of five kinds of fans were analyzed, and the superiority of the selected fan was further verified. The performance tests were carried out on the imported test bed after the processing of the impeller of the selected fan.Verify that the selected fan can meet the flow and pressure requirements.Based on the steady flow field, the unsteady calculation and aerodynamic noise prediction of the selected B / E fan are carried out by using the improved equation of large eddy simulation (les) and Lighthill acoustic analogy (FW-H acoustic model).The predicted and experimental values of sound pressure level at point D of far field noise are compared.The eddy current noise spectrum characteristics of B / E fan with impeller surface as the noise source are analyzed. The vortex distribution characteristics in the three-dimensional unsteady flow field of the fan are studied, and the distribution law of sound pressure level in the fan rotating region is discussed.It is proved that the E fan satisfies the given noise requirement.The time-domain and frequency-domain characteristics of aerodynamic noise at different positions in the rotating region of E fan at different rotational speeds are further discussed.Finally, combined with the summary and deficiency of this paper, the research direction of aerodynamic noise of bending-swept axial fan is put forward.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH432.1

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