Investigation into the generation mechanism of two phase flow induced noise in a bidirectional pump during washing machine drain operation

Sangjin Lee; Sangheon Lee; Cheolung Cheong; Hae-chan Kim; Jinho Choi

doi:10.7776/ASK.2026.45.1.013

All Issue

2026 Vol.45, Issue 1 Preview Page Next Page

Research Article

Investigation into the generation mechanism of two phase flow induced noise in a bidirectional pump during washing machine drain operation 세탁기 양방향 펌프 배수 작동 시 이상 유동에 기인한 소음 발생 메커니즘 분석

31 January 2026. pp. 13-22

PDF XML

Abstract

In this paper, experimental and numerical investigations were conducted to explain the generation mechanism of two phase flow-induced noise occurring in the transient section during the drain operation of a bidirectional pump used in washing machines. First, Short Time Fourier Transform (STFT) Diagram analysis of noise measurements and flow visualization experiments confirmed that air inflow into the housing is the primary cause of flow noise generation in the transient section. To numerically simulate this phenomenon, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations were selected as the governing equations, and a Volume of Fluid (VoF) model based on the homogeneous mixture model was applied to precisely simulate the two-phase flow within the pump housing. The numerical results revealed that the inflow of air into the bidirectional pump housing reduces the fluid torque load on the impeller. This reduction in torque was confirmed to induce rotational noise by causing r/min fluctuations in the transient section due to the motor's control characteristics. Furthermore, it was elucidated that the perturbation of water within the drain pipe induces strong pressure fluctuations on the housing wall, thereby generating two phase flow noise.

Keywords

Bidirectional pump

Flow-induced noise

Two-phase flow

Volume of Fluid (VoF) model

Fluid resistance torque

본 논문에서는 세탁기에 사용되는 양방향 펌프의 배수 작동 시 과도 구간에서 발생하는 유동 소음의 발생 메커니즘을 규명하기 위해 실험적 및 수치적 연구를 수행하였다. 먼저 소음 실험을 통한 Short Time Fourier Transform(STFT) Diagram 분석과 유동 가시화 실험을 통해 공기 유입이 과도 구간의 유동 소음 발생의 주된 원인임을 확인하였다. 이를 수치적으로 모사하기 위해, 전산유체역학 기반의 Unsteady Reynolds-Averaged Navier-Stokes(URANS)을 지배방정식으로 선정하여 유동 해석을 수행하였다. 이때, 양방향 펌프 하우징 내의 이상 유동을 모사하기 위해 균질 유동 모델(Homogeneous mixture model) 기반의 Volume of Fluid(VoF) 모델을 적용하였다. 수치해석 결과를 통해 양방향 펌프 하우징 내부로 공기가 유입되면서, 임펠러에 부하 되는 유체 저항 토크가 감소 됨을 알 수 있었고, 이러한 현상이 과도 구간에서의 일시적인 r/min 상승을 발생시키는 것을 확인하였다. 또한, 배수 배관 내의 물의 섭동이 하우징 벽면에 강한 압력 변동을 발생시켜 유동 소음을 발생시키는 것을 규명하였다.

키워드

양방향 펌프

유동 소음

이상 유동

Volume of Fluid (VoF) 모델

유체 저항 토크

References

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).

10.5050/KSNVE.2016.26.4.428

Y. Song, S.-Y. Ryu, C. Cheong, T.-H. Kim, and J. Koo, “Optimization of impeller blade shape for high-performance and low-noise centrifugal pump” (in Korean), J. Acoust. Soc. Kr. 42, 519-528 (2023).

D.-H. Kim, Y. Noh, O.-K. Lim, E.-H. Choi, and J. Y. Choi, “Design optimization of two-way pump casing through flow analysis” (in Korean), J. Comput. Struct. Eng. Inst. Kr. 31, 79-85 (2018).

10.7734/COSEIK.2018.31.2.79

J. A. Garcia, M. Asuaje, E. Pereyra, and N. Ratkovich, “Analysis of two-phase gas-liquid flow in an electric submersible pump using a CFD approach”, Geoenergy Sci. Eng. 233, 212510 (2024).

10.1016/j.geoen.2023.212510

S. H. Baek, W. H. Jung, and S. Kang, “Shape optimization of impeller blades for biderectional axial flow pump” (in Korean), Trans. Korean Soc. Mech. Eng. B. 36, 1141-1150 (2012).

10.3795/KSME-B.2012.36.12.1141

J. Lee, S. Lee, C. Cheong, T. Kim, and J. Koo, “Analysis of noise generation mechanism for two-phase flow of refrigerant in evaporator inlet pipe of refrigerator” (in Korean), J. Acoust. Soc. Kr. 43, 593-604 (2024).

ISO 3744:2010, Acoustics-Determination of Sound Power Level and Energy Levels of Noise Sources Using Sound Pressure-Engineering Methods for an Essentially Free Field Over a Reflecting Plane, 2010.

ISO 3745:2012, Acoustics-Determination of Sound Power Levels and Sound Energy Levels of Noise Sourves Using Sound Pressure-Precision Method for Anechonic Rooms and Hemi-Anechonic Rooms, 2012.

J. Caridad, M. Asuaje, F. Kenyery, A. Tremante, and O. Aguillom, “Characterization of a centrifugal pump impeller under two-phase flow conditions”, J. Pet. Sci. Eng. 63, 18-22 (2008).

10.1016/j.petrol.2008.06.005

J. L. Parrondo, J. Velarde, and R. R. Santolaria, “Development of a sound generation model for a centrifugal pump” J. Sound Vib. 251, 291-305 (2002).

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 : 45
No :1
Pages :13-22
Received Date : 2025-12-23
Revised Date : 2026-01-19
Accepted Date : 2026-01-28
DOI :https://doi.org/10.7776/ASK.2026.45.1.013

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

All Issue