• Title/Summary/Keyword: MRF (Multiple Reference Frame)

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Analysis of the Generation and Radiation of the Fan Noise by Using Commercial CFD Code (상용 CFD코드를 이용한 냉각홴 공력소음의 발생 및 방사 해석)

  • Jeon, Wan-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.5 no.1 s.14
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    • pp.13-19
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    • 2002
  • In the present study, a numerical simulation is performed for the flow through a cooling fan. The computation was performed by using commercial code, STAR-CD. A rotating fan was simulated by rotational motions using MRF (Multiple Rotating Reference Frame) in a steady-state analysis and sliding interface (rotating meshes) in an unsteady-state analysis. The results of numerical computation were in good agreement with experimental data. In order to calculate the acoustic signal, the unsteady flow-field was firstly calculated. The acoustics of the fan is calculated by using acoustic analogy based on the unsteady flow-field. The predicted acoustic signal shows the characteristics of the uneven bladed-fan.

Suggestion of the Analysis Model and Verification on Rotating Flow in Stirred Tanks Using CFD (전산유체역학을 이용한 교반 탱크 내에서의 회전유동에 대한 해석 모델의 제안 및 검증)

  • Hwang, Seung Sik;Yong, Cho Hwan;Choi, Gyuhong;Shin, Dohghoon;Chung, Tae Yong
    • Journal of Energy Engineering
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    • v.22 no.1
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    • pp.28-37
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    • 2013
  • Stirred tank is widely used in various industries for mixing operations and chemical reactions for single- or multi-phase fluid systems. For designing agitator of high performance, quantity data of internal flow characteristics influenced by mixing performance are definitely confirmed but quantity analysis about the transient flow characteristics of complicate structure is recognized as difficult problem in the present. In this study, two models of commercial CFD code Fluent 6.3 used to propose suitable for the tank analysis. Agitation of Stirred tank is analyzed using a mixed model and the flow in the stirred tank is analyzed using a standard k-${\varepsilon}$ model. Multiple reference frame(MRF) and Sliding mesh(SM), the analysis techniques were used For compare a result of CFD with a visualization experiment result, to grasp internal flow and mixing characteristic in stirred tank and to present fundamental analysis method.

CFD Analysis of Aerodynamic Characteristics of Regional Turboprop Aircraft Propeller (중형 터보프롭 항공기급 프로펠러 공력특성 전산해석)

  • Choi, W.;Choi, J.S.;Jung, I.M.;Kim, J.H.;Lee, I.W.;Han, S.H.;Won, Y.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.447-452
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    • 2011
  • Propeller shall have high efficiency and improved aerodynamic characteristics to get the thru5t to fly at high speed for the Regional turboprop aircraft. That is way Clark-Y airfoil which is used to conventional turboprop aircraft propeller is selected as a blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the propeller design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. propeller geometry is generated by varying chord length and pitch angle at design point of Regional turboprop aircraft. The propeller design results indicate that is evaluated to be properly constructed, through analysis of propeller aerodynamic characteristics using the Meshless method and MRF, SM method.

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A Study on the Optimization of Discharge Grille of Outdoor Unit of Air Conditioner (에어컨 실외기 토출그릴 형상 최적화)

  • Choi, Seok-Ho;Oh, Sai-Kee;Kim, Hyun-Jong;Jin, Geun-Ho;Oh, Si-Young;Kim, Byung-Soon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.11
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    • pp.726-732
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    • 2011
  • The aerodynamic and aeroacoustic performance of discharge grille of outdoor unit of air-conditioner was investigated in this study. Discharge grille is one of outdoor unit's important parts to affect the flow rate and Overall Sound Pressure Level(OSPL). New type of discharge grille was suggested based on the results of numerical simulation. To simulate the flow pattern near the propeller fan, commercial flow solver FLUENT was used. Sliding mesh method was used for rotating propeller fan and initial condition for unsteady model was calculated by Multiple Reference Frame(MRF) method. To minimize the interaction noise between fan blade wake and discharge grille, new discharge grille has radial rib which is aligned with trailing edge of fan blade. And inclined radial rib was adopted for reducing flow rate drop in discharge grille. The optimization of inclined angle of radial grille was performed experimentally.