Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Prediction of Frequency Modulation of BPF Tonal Noise for Random Pitch Cross-Flow Fans by Unsteady Viscous Flow Computations

비정상 점성유동 해석에 의한 부등피치 횡류홴의 BPF 순음 주파수 변조 특성 예측

  • 조용 (고려대학교 대학원) ;
  • 문영준 (고려대학교 기계공학과)
  • Published : 2003.03.01
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Abstract

The unsteady flow characteristics and associated blade tonal noise of a cross-flow fan are predicted by computational methods. The incompressible Navier-Stokes equations are time-accurately solved for obtaining the pressure fluctuations between the rotating blades and the stabilizer. and the sound pressure is predicted using Curie's equation. The discrete noise characteristics of three impellers with a uniform and two random pitch (type-A and -B) blades are compared by their SPL (Sound Pressure Level) spectra. and the frequency modulation characteristics of the BPF (Blade Passing Frequency) noise are discussed. Besides. a mathematical model is proposed for the prediction of discrete blade tonal noise and is validated with available experimental data. The fan performance is also compared with experimental data. indicating that the random pitch effect does not significantly alter the performance characteristics at ${\phi}$ 〉 0.4

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References

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