• Title/Summary/Keyword: Axial flow fan

Search Result 234, Processing Time 0.034 seconds

The Study on Performance of an Axial Fan with Centrifugal type Blades in Duct flow (덕트 내 원심식 축류팬의 성능변화에 관한 연구)

  • Han, Jae-Oh;Lee, Soo-Young;Yu, Seung-Hun;Lee, Jai-Kwon
    • 유체기계공업학회:학술대회논문집
    • /
    • 2006.08a
    • /
    • pp.213-216
    • /
    • 2006
  • This paper was a study about noise reduction through flow stabilization in duct using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type blades) was examined to investigate the suitability for in-line duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type blades was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ}$, $10^{\circ}$, $15^{\circ}$ and $20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}$ to $20^{\circ}$, and embodied noise reduction and improvement of air flow rate through flow stabilization.

  • PDF

Improvement in flow and noise performances of small axial-flow fan for automotive fine dust sensor (차량용 미세먼지 센서용 소형 축류팬의 유동과 소음 성능 개선)

  • Younguk Song;Seo-Yoon Ryu;Cheolung Cheong;Inhiug Lee
    • The Journal of the Acoustical Society of Korea
    • /
    • v.42 no.1
    • /
    • pp.7-15
    • /
    • 2023
  • Recently, as interest in air quality in vehicles increases, the use of fine dust detection sensors for air quality measurement is becoming common. An axial-flow fan is inserted in the fine dust sensor installed in the air conditioning system in the vehicle to prevent dust from sinking directly on the sensor. When the sensor operates, the flow noise caused by the rotation of the axial-flow fan acts as a major noise source of the fine dust sensor. flow noise is recognized as one of the product competitiveness of fine dust sensors. In this study, the noise was gradually reduced at the same flow rate by improving the flow performance of the small axial flow fan. First, a virtual fan performance tester consisting of about 20 million grids was developed to analyze the aerodynamic performance of the target small axial-flow fan. In addition, the flow field was simulated by using compressible Large Eddy Simulation for direct computation of flow noise as well as high-accurate prediction of flow rate. The validity of numerical method are confirmed through the comparison of predicted results with experimental ones. After the effects of pitch angle on flow performance were analyzed using the verified numerical method, the pitch angle was determined to maximize the flow rate. It was found that the flow rate was increased by 8.1 % and noise was reduced by 0.8 dBA when the axial-flow fan with the optimum pitch angle was used.

A Computerized Axial Flow Fan Design System for Noise and Performance Analysis (성능 및 소음 해석 기능이 수반된 전산화된 축류 송풍기 설계 체제)

  • Chung, Dong-Kyu;Noh, Jun-Gu;Seo, Jae-Young;Lee, Chan
    • 유체기계공업학회:학술대회논문집
    • /
    • 2001.11a
    • /
    • pp.37-42
    • /
    • 2001
  • A computerized axial flow fan design system is developed with the capabilities for predicting the aerodynamic performance and the noise characteristics of fan. In the present study, the basic fan blading design is made by combining vortex distribution scheme with camber line design, airfoil selection, blade thickness distribution and stacking of blade elements. With the designed fan blade geometry, the through-flow field and the performance of fan are analyzed by using the streamline curvature computing scheme with spanwise total pressure loss and flow deviation models. Fan noise is assumed to be generated due to the pressure fluctuation induced by wake vortices of fan blades and to radiate as dipole distribution. The vortex-induced fluctuating pressure on blade surface is calculated by combining thin airfoil theory and the predicted flow field data. The predicted performances, sound pressure level and noise directivity patterns of fan by the present method are favorably compared with the test data of actual fans. Furthermore, the present method is shown to be very useful in designing the blade geometry of new fan and optimizing design variables of the fan to achieve higher efficiency and lower noise level.

  • PDF

NUMERICAL ANALYSIS OF UNSTEADY FLOW FIELD AND AEROACOUSTIC NOISE OF AN AXIAL FLOW FAN (축류팬의 비정상 유동장 및 유동소음의 수치 해석)

  • Kim, Wook;Hur, Nahm-Keon;Jeon, Wan-Ho
    • Journal of computational fluids engineering
    • /
    • v.15 no.4
    • /
    • pp.60-66
    • /
    • 2010
  • Unsteady Reynolds Averaged Navier-Stokes(URANS) and Large Eddy Simulation(LES) simulation of an axial flow fan are calculated upon same conditions and computational grids in order to study aeroacoustic noise of an axial flow fan numerically. Results of computed performance and predicted noise are compared with those of measurement. Both performances show accurate results with a significant difference of less than 5%. However, noise of LES result is more close to measured noise qualitatively than URANS. Levels of tonal noises of both LES and URANS are quite similar with those of measured at BPF(Blade Passing Frequency) in sound spectrum. However, as leading edge separation and tip vortex shedding phenomena of LES are showed more clearly than those of URANS, sound level of broadband noise of LES corresponds better than that of URANS, especially.

Vibration Reduction of an Air Cooled Heat Exchanger with Axial Flow Fan (축류송풍기 부착형 공냉식 열교환기의 진동저감)

  • 정구충;최연선
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.11 no.6
    • /
    • pp.163-168
    • /
    • 2001
  • Vibration problems occurred in an air cooled heat exchanger with axial flow fan for a petrochemical plant were investigated. Experimental field test and theoretical verification were performed. To find the main cause of the high vibration of the fan at the air inlet of the axial fan, the frequency spectrum was measured. The natural frequency of the driving support of the heat exchanger was numerically calculated. Both of the measured and the natural frequency were approximately equal to the blade passing frequency. Because it was difficult to modify the structure of the driving support during the normal operation of the plant, the blade number of the fan was increased, which greatly reduced the vibration level of the heat exchanger.

  • PDF

Velocity Field Measurement of Flow Around an Axial Fan Using a Phase Averaged 2-Frame PTV Technique (위상평균 PTV 기법을 이용한 축류 홴 주위 유동의 속도장 측정 연구)

  • Choi, Jay-Ho;Kim, Hyoung-Bum;Lee, Sang-Joon;Lee, In-Seop
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.1
    • /
    • pp.114-123
    • /
    • 2000
  • The flow structure around a rotating axial-fan was experimentally investigated using a phase averaging velocity field measurement technique. The fan blades were divided into 4 different phases, for which 500 velocity fields were acquired for each phase angle with a 2-frame PTV system. Velocity field measurements were also carried out at two planes parallel to the axis of rotation, with offsets toward the radial direction of the fan. For accurate synchronization of the PTV system with the phase of the axial fan, two synchronization circuits were employed with a photo-detector attached to the rotating shaft. The phase averaged velocity fields show periodic variations with respect to the blade phase. The periodic formation of vortices at the blade tip is also observed in vorticity contour plots. Locations of local maximum turbulence intensities in the axial and radial directions are found to be located in an alternating pattern. These experimental results can be used to validate numerical calculations and to understand the flow characteristics of an axial fan.

An Estimation of Performance Test and Uncertainty of Measurement for a Large Axial-flow Fan Based on ANSI/AMCA 210 Standard (ANSI/AMCA 210 기준에 의한 대형 축류 송풍기의 성능시험 및 측정 불확도 평가)

  • Ko, Hee-Hwan;Chung, Cheol-Young;Kim, Kyung-Yup
    • The KSFM Journal of Fluid Machinery
    • /
    • v.17 no.2
    • /
    • pp.24-29
    • /
    • 2014
  • In general, a large-capacity axial flow fan is used for industrial processes or ventilation in a social overhead capital infrastructure. The main characteristics of the large axial-flow fan need a lot of electrical power consumption and operate 24 hours a day, 365 days a year. Since the large axial flow fan consumes several hundreds to thousands kW per hour, both manufacturer and consumer are struggling to select high efficiency products for saving energy and reducing operation cost. Therefore, the performance testing should be accurately conducted in experimental equipments. The performance estimation and uncertainty of measurement of the axial-flow fan gathered from the result from nozzle shaped testing equipments certified with ANSI/AMCA standard and duct shaped testing equipment under the same experimental condition. The experimental results from both facilities have maximum 17% differences in performance evaluation and uncertainty of measurement. As considering that the differences, it is doubt about the reliability of testing result. The test was repeated with the specific term during 12 months because it is important to fully reflect the real conditions and to decide the repeatability of data. The evaluation of duct type testing facilities was failed to get an uncertainty measure. Testing results were previously published. As a series of previous paper, axial fan (∅1690 mm) and duct type testing facilities were fabricated. The purpose of fabricating testing equipment was testing an uncertainty measurement under the controlled environments.

Study on Noise Reduction by Optimizations of In-line Duct Flow (덕트의 유로 최적화를 통한 소음저감 연구)

  • Han, Jae-Oh;Lee, Soo-Young;Mo, Jin-Yong;Lee, Jai-Kwon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2006.05a
    • /
    • pp.803-808
    • /
    • 2006
  • This paper was a study about noise reduction through flow stabilization in duel using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type) was examined to investigate the suitability for duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ},\;10^{\circ},\;15^{\circ}\;and\;20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}\;to\;20^{\circ}$. Finally, designed the shapes of D/S(Down Stream) in duct that agreed inlet angle($\delta$) of stationary blades with pitch angle($\beta$) of axial fan with centrifugal type and derived flow to duct medial, and changed the shape of motor-mount to reduce occurance of unstable vortex in tip of impeller, and embodied noise reduction and improvement of air flow rate through flow stabilization.

  • PDF

Unsteady Flow Characteristics of an Axial Flow Fan Installed in the Outdoor Unit of Air Conditioner (에어콘 실외기용 축류송풍기의 비정상 유동장 특성 연구)

  • Jang, Choon-Man
    • 유체기계공업학회:학술대회논문집
    • /
    • 2005.12a
    • /
    • pp.223-230
    • /
    • 2005
  • The unsteady nature of vortex structures has been investigated by a large eddy simulation (LES) in an axial flow fan with a shroud covering only the rear region of its rotor tip. The simulation shows that the tip vortex plays a major role in the structure and unsteady behavior of the vortical flow in the fan. The movements of the vortex structures induce high-pressure fluctuations on the rotor blade and in the blade passage. Frequency characteristics of the fluctuating pressure on the rotor blade are analyzed using wavelet transform. The dominant frequency of the real-time pressure selected at the high pressure fluctuation region corresponds well to that of the fluctuating rotor torque and the experimental result of fan noise. It is mainly generated due to the unsteady behavior of the vortical flow, such as the tip vortex and the leading edge separation vortex.

  • PDF

The performance and flow characteristics of a small propeller fan with a back-plate (뒷판이 있는 소형 프로펠러 팬의 성능 및 유동특성)

  • Gang, Sin-Hyeong;Kim, Jin-Gwon;Lee, Seung-Bae
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.20 no.4
    • /
    • pp.1491-1500
    • /
    • 1996
  • Unstable performance deterioration was found on the performance curve of a small propeller fan with a back plate. To investigate this phenomenon and the effects of the back-plate on the performance of the fan, performance tests and flow measurement using 3-hole pitot tube were carried out. Measurements showed that when the flow rate is small, the radial flow dominates, and when the flow rate is large, the axial flow dominates. Performance characteristic of the propeller fan changes from radial to axial type as the flow rate increases. Unstable performance changes are the result of type change of the flow through the fan.