Numerical and experimental investigations on the aerodynamic and aeroacoustic performance of the blade winglet tip shape of the axial-flow fan

Seo-Yoon Ryu; Cheolung Cheong; Jong Wook Kim; Byeong Il Park

doi:10.7776/ASK.2024.43.1.103

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2024 Vol.43, Issue 1 Preview Page Next Page

Research Article

Numerical and experimental investigations on the aerodynamic and aeroacoustic performance of the blade winglet tip shape of the axial-flow fan 축류팬 날개 끝 윙렛 형상의 적용 유무에 따른 공기역학적 성능 및 유동 소음에 관한 수치적/실험적 연구

31 January 2024. pp. 103-111

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Abstract

Axial-flow fans are used to transport fluids in relatively low-pressure flow regimes, and a variety of design variables are employed. The tip geometry of an axial fan plays a dominant role in its flow and noise performance, and two of the most prominent flow phenomena are the tip vortex and the tip leakage vortex that occur at the tip of the blade. Various studies have been conducted to control these three-dimensional flow structures, and winglet geometries have been developed in the aircraft field to suppress wingtip vortices and increase efficiency. In this study, a numerical and experimental study was conducted to analyze the effect of winglet geometry applied to an axial fan blade for an air conditioner outdoor unit. The unsteady Reynolds-Averaged Navier-Stokes (RANS) equation and the Ffocws-Williams and Hawkings (FW-H) equation were numerically solved based on computational fluid dynamics techniques to analyze the three-dimensional flow structure and flow noise numerically, and the validity of the numerical method was verified by comparison with experimental results. The differences in the formation of tip vortex and tip leakage vortex depending on the winglet geometry were compared through a three-dimensional flow field, and the resulting aerodynamic performance was quantitatively compared. In addition, the effect of winglet geometry on flow noise was evaluated by numerically simulating noise based on the predicted flow field. A prototype of the target fan model was built, and flow and noise experiments were conducted to evaluate the actual performance quantitatively.

Keywords

Axial-flow fan

Winlget shape

Tip vortex

Tip leakage vortex

축류팬은 상대적으로 저압의 유동 영역에서 유동을 수송하기 위해 사용되며, 다양한 설계 변수에 대해 설계된다. 축류팬의 날개 끝 형상은 유동 및 소음 성능에 지배적인 역할을 수행하며 이에 대한 대표적인 유동 현상으로 날개 끝에서 발생하는 날개 끝 와류와 누설 와류가 있다. 이러한 3차원 유동 구조를 제어하기 위해 다양한 연구가 수행되어 왔으며, 항공기 분야에서 날개 끝 와류를 억제하고 효율을 증가시키기 위해 윙렛 형상이 개발되었다. 본 연구에서는 에어컨 실외기용 축류팬 날개에 적용된 윙렛 형상의 영향을 분석하기 위한 수치적, 실험적 연구를 수행하였다. 3차원 유동 구조 및 유동 소음을 수치적으로 분석하기 위해 unsteady Reynolds-Averaged Navier-Stokes(RANS) 방정식과 Ffocws-Williams and Hawkings(FW-H) 방정식을 전산유체역학 기법에 기초하여 수치 해석하였으며, 실험 결과와의 비교를 통해 수치 기법의 유효성을 검증하였다. 윙렛 형상에 따른 날개 끝 와류와 누설 와류의 형성의 차이를 3차원 유동장을 통해 비교하고, 그에 따른 공기역학적 성능을 정량적으로 비교하였다. 또한, 예측 유동장을 바탕으로 소음을 수치적으로 모사하여 윙렛 형상이 유동 소음 측면에 미치는 영향을 분석하였다. 대상 팬 모델의 시제품을 제작하여 유동 및 소음 실험을 실시하여 실제 성능을 정량적으로 평가하였다.

키워드

축류팬

윙렛 형상

날개 끝 와류

누설 와류

References

S.-Y. Ryu, S. Kim, C. Cheong, J.-U. Kim, B. I. Park, and S. M. Park, "Optimization of flow performance by designing orifice shape of outdoor unit of air-conditioner" (in Korean), J. Acoust. Soc. Kr. 36, 371-377 (2017).

R. T. Whitcomb, "A design approach and selected wind tunnel results at high subsonic speeds for wing-tip mounted winglets," NASA Tech. Rep., L-10908, 1976.

P. Andersen, J. Friesch, J. J. Kappel, L. Lundegaard, and G. Patience, "Development of a marine propeller with nonplanar lifting surfaces," MAR. TECHNOL. SNAME. N. 42, 144-158 (2005). 10.5957/mt1.2005.42.3.144

T. Benedek, J. Vad, and B. Lendvai, "Combined acoustic and aerodynamic investigation of the effect of inlet geometry on tip leakage flow noise of free-inlet free-exhaust low-speed axial flow fans" Appl. Acoust. 187, 108488 (2022). 10.1016/j.apacoust.2021.108488

K. Park, H. Choi, S. Choi, and Y. Sa, "Effect of a casing fence on the tip-leakage flow of an axial flow fan," Int. J. Heat Fluid Flow, 77, 157-170 (2019). 10.1016/j.ijheatfluidflow.2019.04.005

S. M. A. Moghadam, M. Meinke, and W. Schröder, "Analysis of tip-leakage flow in an axial fan at varying tip-gap sizes and operating conditions," Comput. Fluids, 183, 107-129 (2019). 10.1016/j.compfluid.2019.01.014

M. Zhang, Y. Cao, and C. Zhou, "Flow physics and loss mechanisms of tip leakage flow in variable-blade-pitch-angle ducted fans," Aerosp. Sci. Technol. 142, 108588 (2023). 10.1016/j.ast.2023.108588

KS C 9306; Korean Standards Association, Room Air-Conditioners, 2002.

ANSI/AMCA 210-07, Laboratory Methods of Testing Fans for Certified Aerodynamic Performance Rating, 2018.

V. Yakhot and S. A. Orszag, "Renormalization group analysis of turbulence. I. Basic theory," J. Sci. Comput. 1, 3-51 (1986). 10.1007/BF01061452

J. C. R. Hunt, A. A. Wray, and P. Moin, "Eddies, streams, and convergence zones in turbulent flows," Proc. CTR summer program, 193-208 (1988).

Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 43
No :1
Pages :103-111
Received Date : 2023-12-20
Accepted Date : 2024-01-10
DOI :https://doi.org/10.7776/ASK.2024.43.1.103

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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