The Journal of the Acoustical Society of Korea (한국음향학회지)

The Acoustical Society of Korea (한국음향학회)
권호 표지
DOI QR코드

DOI QR Code

Optimal design of impeller in fan motor unit of cordless vacuum cleaner for improving flow performance and reducing aerodynamic noise

무선진공청소기 팬 모터 단품의 유량성능 향상과 공력소음 저감을 위한 임펠라 최적설계

  • Received : 2020.07.21
  • Accepted : 2020.09.10
  • Published : 2020.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the flow and noise performances of high-speed fan motor unit for cordless vacuum cleaner is improved by optimizing the impeller which drives the suction air through flow passage of the cordless vacuum cleaner. Firstly, the unsteady incompressible Reynolds averaged Navier-Stokes (RANS) equations are solved to investigate the flow through the fan motor unit using the computational fluid dynamics techniques. Based on flow field results, the Ffowcs-Williams and Hawkings (FW-H) integral equation is used to predict flow noise radiated from the impeller. Predicted results are compared to the measured ones, which confirms the validity of the numerical method used. It is found that the strong vortex is formed around the mid-chord region of the main blades where the blade curvature change rapidly. Given that vortex acts as a loss for flow and a noise source for noise, impeller blade is redesigned to suppress the identified vortex. The response surface method using two factors is employed to determine the optimum inlet and outlet sweep angles for maximum flow rate and minimum noise. Further analysis of finally selected design confirms the improved flow and noise performance.

본 논문에서는 무선진공청소기용 팬 모터 단품의 유량 및 소음성능을 향상시키기 위하여 무선청소기 유로를 통하여 공기를 흡입하는 임펠라에 대한 최적설계를 수행하였다. 우선, 팬 모터 단품, 특히 임펠라의 유동장을 분석하기 위하여 비정상, 비압축성 Reynolds averaged Navier-Stokes(RANS) 방정식을 전산유체역학(Computational Fluid Dynamics, CFD)에 기초하여 해석하였다. 예측한 유동장 정보를 입력값으로 Ffowcs-Williams and Hawkings(FW-H) 방정식을 사용하여 임펠라로부터 방사되는 소음을 수치적으로 예측하였다. 유량과 소음에 대한 수치해석 결과를 실험을 통해 측정한 팬 모터 단품의 P-Q 곡선과 음압 스펙트럼과 비교하여 사용한 수치방법의 유효성을 확인하였다. 수치해석결과로부터 임펠라 날개의 코드방향 중간부분의 급격한 곡률 변화로 인하여 강한 와류가 형성되는 것을 확인하였다. 와류는 유동에는 손실로 소음에는 소음원으로 작용하기 때문에 기존의 임펠라를 재설계하여 와류를 개선하고자 하였다. 2인자 반응표면방법을 사용하여 최대유량과 최소소음을 나타내는 입·출구 뒷젖힘각(sweep angle)을 결정하였다. 최종 선정된 설계안에 대한 추가 해석을 통하여 유량성능과 소음성능이 개선됨을 확인하였다.

Keywords

References

  1. S. Lee, S. Heo, and C. Cheong, "Prediction and reduction of internal blade-passing frequency noise of the centrifugal fan in a refrigerator," IJR. 33, 1129-1141 (2010).
  2. S. Heo, C. Cheong, and T. H. Kim, "Development of low-noise centrifugal fans for a refrigerator using inclined S-shaped trailing edge," IJR. 34, 2076-2091 (2011).
  3. S. Heo, C. Cheong, and T. Kim, "Unsteady fast random particle mesh method for efficient prediction of tonal and broadband noises of a centrifugal fan unit," AIP Advances, 5, 097133 (2015). https://doi.org/10.1063/1.4930979
  4. S. Heo, M. Ha, T. H. Kim, and C. Cheong, "Development of high-performance and low-noise axial-flow fan units in their local operating region," JMST. 29, 3653-3662 (2015).
  5. G. Ren, S. Heo, T. H. Kim, and C. Cheong, "Response surface method-based optimization of the shroud of an axial cooling fan for high performance and low noise," JMST. 27, 33-42 (2013).
  6. S. M. Park, S. Y. Ryu, C. Cheong, J. W. Kim, B. I. Park, Y. C. Ahn, and S. K. Oh, "Optimization of the orifice shape of cooling fan units for high flow rate and low-level noise in outdoor air conditioning units," Applied Sciences, 9, 5207 (2019). https://doi.org/10.3390/app9235207
  7. D. Shin, S. Y. Ryu, C. Cheong, T. H. Kim, and J. Jung, "Development of high-performance/low-noise centrifugal fan circulating cold air inside a household refrigerator by reduction of vortex flow" (in Korean), Trans. Korean Soc. Noise Vib. Eng. 26, 428-435 (2016). https://doi.org/10.5050/KSNVE.2016.26.4.428
  8. J. Choi, S. Y. Ryu, C. Cheong, M. K. Kim, and K. Lee, "Blade shape optimization of centrifugal fan for improving performance and reducing aerodynamic noise of clothes dryer" (in Korean), J. Acoust. Soc. Kr. 38, 321-327 (2019).
  9. I. H. Son, Y. Noh, E. H. Choi, J. Y. Choi, Y. J. Ji, and K. Lim, "Optimization of the flow path efficiency in a vacuum cleaner fan," SV. JME. 64, 258-268 (2018).
  10. W. Jansen and A. M. Kirschner, "Impeller blade design method for centrifugal compressors," Proc. Symposium on Fluid Mechanics, NASA-SP-304, 537-563 (1967).
  11. E. I. G. Velásquez, M. A. R. Nascimento, R. A. M. Carrillo, and N. R. Moura, "One and three-dimensional analysis of centrifugal compressor for 600 kW simple cycle gas turbine engine," Turbo Expo: Power for Land, Sea, and Air. 44007, 471-476 (2010).
  12. J. Zhang, C. Xu, Y. Zhang, and X. Zhou, "Quasi-3D hydraulic design in the application of an LNG cryogenic submerged pump," J.NGE. 29, 89-100 (2016).
  13. S. Y. Cho, Y. D. Lee, K. Y. Ahn, and Y. C. Kim, "A study on the design method to optimize an impeller of centrifugal compressor" (in Korean), The KSFM j. Fluid Machinery, 16, 11-16 (2013).
  14. C. H. Park, K. H. Park, and K. S. Chang, "Systemlevel analysis of a fan-motor assembly for vacuum cleaner" (in Korean), The KSFM j. Fluid Machinery, 20, 5-14 (2017).
  15. A. S. Lyrintzis, "Surface integral methods in computational aeroacoustics-From the (CFD) near-field to the (Acoustic) far-field," Int. J. Aeroacoustic, 2, 95-128 (2003). https://doi.org/10.1260/147547203322775498