以大涡模拟得到的泵内全三维非稳态流场为基础，通过设置外部监测点对声压信号进行频域分析的方法，以额定转速为1450r/min的离心泵为对象，基于FW-H声学模型研究了转速在1000r/min到6000r/min之间变化时泵内蜗壳辐射噪声的变化规律，揭示了辐射噪声与转速之间的响应关系，通过对蜗壳压力脉动强度和流场均匀性指标的分析研究，获得了转速对辐射噪声影响的根本原因。模拟结果表明：蜗壳辐射噪声随叶轮转速的增加而非线性单调增大，且在2000-2500r/min的转速区间（占总区间10%）内，蜗壳辐射噪声急剧增大（增量约为额定工况噪声7%）。同时，蜗壳辐射噪声整体上呈现指向性分布，即‘正对隔舌噪声大、背对隔舌噪声小’的偏心分布。该结论可为离心泵变频运行中有效避开高辐射噪声工况提供指导，为低噪声离心泵的三维设计奠定基础。
Abstract
In this paper, to investigate the centrifugal pump with the design rotational speed 1450r/min, based on the flow field explored by the 3D unsteady Large Eddy Simulation (LES) model, through setting the external monitoring points and the method of Fourier transform of their sound pressure signals, the changing rules of noise radiation in the pump are analyzed when the rotational speed increases from 1000 to 6000r/min base on FW-H acoustic model and the relationship between radiation noise and rotational speed is revealed as well. Moreover, the pressure fluctuations on the volute surface are calculated and the uniformity evaluation standard is also established to analyze the direct and underlying causes for the volute radiation noise. It is interesting to find that the volute radiation noise represents a non-linear rise with the increase of rotational speed, and especially while increasing from 2000 to 2500r/min (10% of the whole range), the radiation noise rockets drastically (7% increase compared with the noise under design condition). Meanwhile, the distribution of noise radiation shows directivity; that is the noise of areas towards the volute tongue is significantly higher than that of areas back to it. These conclusions make guidance how to avoid the loud noise as a variable-speed adjustment and lay a foundation for 3D design of low-noise centrifugal pumps.
关键词
离心泵 /
FW-H声学模型 /
变转速工况 /
蜗壳辐射噪声 /
变化规律
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Key words
Centrifugal pump /
FW-H acoustic model /
Variable rotational speed conditions /
Volute radiation noise /
Changing rules
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