• 제목/요약/키워드: Axial flow

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엇회전식 축류홴의 공력 특성에 관한 실험적 연구 (Experimental Study on the Aerodynamic Characteristics of a Counter-Rotating Axial Fan)

  • 최진용;조이상;조진수;원유필
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집B
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    • pp.441-446
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    • 2000
  • The experiments of the Aerodynamic characteristics of a counter-rotating axial fan were carried out. The performance tests of a single and a counter-rotating axial fan were carried out based on the Korean Standard Testing Methods for Turbo-fans and Blowers(KS B 6311). The performances of single and counter-rotating axial fans were obtained and compared with each other. The flow fields of a counter-rotating axial fan at the peak efficiency point were measured using a five-hole probe. As a result, compared with the performance of a single-rotating axial fan, that of a counter-rotating axial fan was superior. And it is confirmed that most of the swirl flow generated by the front rotor was eliminated by the rear rotor.

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원심형 보조날개를 부착한 축류홴의 유동특성에 관한 실험적 연구 (An Experimental Study on the Flow Characteristics of Axial Flow Fan with Centrifugal Sub-Blade)

  • 이석종;성재용;이명호
    • 한국지열·수열에너지학회논문집
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    • 제9권3호
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    • pp.19-25
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    • 2013
  • A new type axial flow fan with centrifugal sub-blades has been designed and fabricated in the present study. We investigated velocity and pressure distributions in downstream flow fields of the fan experimentally to detect the detailed flow characteristics of new axial flow fan and an existing axial flow fan. Two-dimensional velocity components were probed by applying a particle image velocimetry system and pressure distributions were measured by Pitot tube and micro-manometer. Our results show that the velocity and pressure distributions at the flow fields of the new fan are quite different from the existing fan, and that the centrifugal sub-blades in the new fan can improve the performance characteristics in view of kinetic energy.

Predictions of non-uniform tip clearance effects on the flow field in an axial compressor

  • Kang, Young-Seok;Kang, Shin-Hyoung
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년 영문 학술대회
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    • pp.743-750
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    • 2008
  • Asymmetric tip clearance in an axial compressor induces pressure and velocity redistributions along the circumferential direction in an axial compressor. This paper presents the mechanism of the flow redistribution due to the asymmetric tip clearance with a simple numerical modeling. The flow field of a rotor of an axial compressor is predicted when an asymmetric tip clearance occurs along the circumferential direction. The modeling results are supported by CFD results not only to validate the present modeling but also to investigate more detailed flow fields. Asymmetric tip clearance makes local flow area and resultant axial velocity vary along the circumferential direction. This flow redistribution 'seed' results in a different flow patterns according to the flow coefficient. Flow field redistribution patterns are largely dependent on the local tip clearance performance at low flow coefficients. However, the contribution of the main flow region becomes dominant while the tip clearance effect becomes weak as the flow coefficient increases. The flow field redistribution pattern becomes noticeably strong if a blockage effect is involved when the flow coefficient increases. The relative flow angle at the small clearance region decreases which result in a negative incidence angle at the high flow coefficient. It causes a recirculation region at the blade pressure surface which results in the flow blockage. It promotes the strength of the flow field redistribution at the rotor outlet. These flow pattern changes have an effect on the blade loading perturbations. The integration of blade loading perturbation from control volume analysis of the circumferential momentum leads to well-known Alford's force. Alford's force is always negative when the flow blockage effects are excluded. However when the flow blockage effect is incorporated into the modeling, main flow effects on the flow redistribution is also reflected on the Alford's force at the high flow coefficient. Alford's force steeply increases as the flow coefficient increases, because of the tip leakage suppression and strong flow redistribution. The predicted results are well agreed to CFD results by Kang and Kang(2006).

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고성능 엇회전식 축류팬의 공력특성에 대한 전산해석 (Numerical analyses on the Aerodynamic Characteristics of a Counter-rotating Axial Flow Fan)

  • 조이상;조진수
    • 융복합기술연구소 논문집
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    • 제5권1호
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    • pp.37-40
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    • 2015
  • Numerical analyses on the aerodynamic characteristics of a counter rotating axial flow fan is carried out using the frequency domain panel method. Front rotor and rear rotor blades of a counter rotating axial fan are designed by using the simplified meridional flow analysis method with the radial equilibrium equation and the free vortex design condition, according to design requirements. Performance characteristics of a counter rotating axial flow fan are estimated for the variation of design parameters such as the hub to tip ratio, the taper ratio and the solidity. Pressure losses were higher at leading edge and hub region of rotor blades. Characteristic curve of the counter rotating fan was overpredicted without consideration of viscous effect.

지하역사 공기조화기용 축류형 사이클론 클러스터의 수치해석적 성능 평가 연구 (Numerical Study of Axial-flow Cyclone Cluster for Subway Station HVAC system)

  • 김명준;김호중;김진관;권순박;김태성
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.757-761
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    • 2009
  • Axial-flow cyclone separator cluster can be used for a dust removal device inside a heating, ventilation, and air conditioning(HVAC) system of subway station. In this study, 3-dimensional computational fluid dynamics(CFD) analysis was performed to compare single unit axial-flow cyclone with couple unit axial-flow cyclone cluster. It is shown that the performance of cyclone separator is not influenced by number of single units but influenced by ability of single unit.

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시스템 특성을 고려한 축류팬 저소음화에 대한 연구 (Study on Noise Reduction of An Axial Flow Fan According to the System Characteristics)

  • 윤홍열;김창준;송성배
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.1381-1385
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    • 2000
  • In this paper, a guideline of axial flow fan design for noise reduction of refrigerators is p resented. Refrigerators have components which have a role to screen particular frequency air borne-noise which is generated by an axial flow fan set in them. Effective ways to use the particular characteristic of refrigerators are shown in this study. As a result of application of the methods, we reduced the noise of the target systems by more than 3 dB(A) from the viewpoint of air-borne noise produced by the axial flow fan set.

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전산유체해석을 이용한 축류형 혈액펌프의 용혈평가 (Evalution of Hemolysis in Axial Flow Blood Pump with Computational Fluid Dynamics Analysis)

  • 임상필;김동욱
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2003년도 춘계학술발표논문집
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    • pp.256-259
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    • 2003
  • Artificial heart is divided pulsation style and nonpulsation style greatly according to flowing of blood. nonpulsation pump is advantage of miniaturization avaliable because it is simple and non-volumic-pump than pulsation pump. Non pulsation pump is derided axial flow style and centrifugal style accordig to rotating style. An axial flow blood pump can be made smaller than a centrifugal blood pump because of its higher specific speed. A hemolysis is an important factor for the development of an axial flow blood pump. It is difficult to identify the areas where hemolysis nun. Evaluation of hemolysis both in in vitro and in vivo require a long time and are costly. Computational fluid dynamics(CFD) analysis enables the engineer to predict hemolysis on a computer. The aims of this study is Computational fluid dynamics in the whole axial flow pump and to verify the accuracy of prediction results of CFD analysis compare with in vitro experimental results.

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냉장고용 소형 축류홴의 통계학적 3차원 난류유동 특성에 관한 연구 (A Study on the Three Dimensional Statistical Turbulent Flow Characteristics Around a Small-Sized Axial Fan for Refrigerator)

  • 김장권
    • 대한기계학회논문집B
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    • 제25권6호
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    • pp.819-828
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    • 2001
  • The operating point of a small-sized axial fan is strongly dependent upon the system resistance. Therefore, the turbulent flow characteristics around a small-sized axial fan may change significantly according to the operating point. This study represents three-dimensional turbulent flow characteristics around a small-sized axial fan measured at the ideal design point $\phi$=0.25, which is equivalent to the maximum total efficiency point, by using three dimensional fiber-optic type LDA system. This LDA system is composed of a 5 W Argon-ion laser, two optics in back-scatter mode, three BSAs, a PC, and a three-dimensional automatic traversing system. A kind of paraffin fluid is used to supply particles by means of fog generator. Mean velocity profiles downstream of a small-sized axial fan along the radial distance show that the streamwise and the tangential components exist in a predominant manner, while the radial component has a small scale distribution and shows the inflection which its flow direction is inward or outward. Moreover, the turbulent intensity profiles show that the radial component exists the most greatly among turbulent energies.

1단 터빈에서 축간격 변화가 비정상 이차유동 및 성능에 미치는 영향 (The effects of axial spacing on the unsteady secondary and performance in one-stage axial turbine)

  • 박준영;백제현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.537-540
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    • 2002
  • Flow through turbomachinery has a very complex structure and is intrinsically unsteady. Especially, recent design trend to turbomachinery with short axial spacing makes the flow extremely complex due to the interaction between stator and rotor. Therefore, it is very necessary to clearly understand the complex flow structure to obtain the high efficiency turbomachinery. So, in this paper, the effects of axial spacing on the unsteady secondary flow performance in the one stage turbine are investigated by three-dimensional unsteady flow analysis. The three-dimensional solver is parallelized using domain decomposition and Message Passing Interface(MPI) standard to overcome the limitation of memory and the CPU time in three-dimensional unsteady calculation. A sliding mesh interface approach has been implemented to exchange flow information between blade rows.

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원심형 날개를 부착한 축류홴의 유동특성 해석 (Analysis of Flow Characteristics on the Axial Flow Fan with Centrifugal Blade)

  • 최중근;이석종;이명호;성재용
    • Journal of Advanced Marine Engineering and Technology
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    • 제30권5호
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    • pp.589-596
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    • 2006
  • This study aims to propose a new model axial flow fan which attachs centrifugal blades, and to investigate the effect of centrifugal blades on the performance improvement of new model axial flow fan. A numerical simulation has been conducted using STAR-CD commercial code to solve the three dimensional incompressible Navier-Stokes equation for high Reynolds number $k-{\epsilon}$ turbulent model. Numerical simulation is carried out to investigate the detail phenomenon in the flow field and performance characteristics of new model and normal model fan. Calculation results are compared with normal model's results to investigate which centrifugal blades effect on velocity profile and pressure distribution at various flow field positions. and calculation results show that new model fan can improve the performance of total pressure.