Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Characteristics of Developing Turbulent Oscillatory Flows in a 180° Curved Duct with a Square Sectional by using a LDV

LDV에 의한 정사각 단면 180° 곡덕트에서 난류진동유동의 유동특성

  • Yun, Seok-Ju (Department of Mechanical Engineering, Graduate School of Chosun University) ;
  • Lee, Haeng-Nam (Department of Mechanical Engineering, Chosun University) ;
  • Sohn, Hyun-Chull (Department of Mechanical Engineering, Chosun University)
  • Received : 2014.12.29
  • Accepted : 2015.06.03
  • Published : 2015.07.10
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Abstract

In the present study the characteristics of turbulent oscillatory flows in a square-sectional $180^{\circ}$curved duct were investigated experimentally. A series of experiments for air flow were conducted to measure axial velocity profiles, secondary flow velocity profiles and pressure distributions. The measurements were made by a Laser Doppler Velocimeter (LDV) system with a data acquisition and processing system which includes Rotating Machinery Resolve (RMR) and PHASE software. The results from the experiment are summarized as follows. (1) The maximum velocity moved toward the outer wall from the region of a bend angle of $30^{\circ}$. The velocity distribution had a positive value extended over the total phase in the region of a bend angle of $150^{\circ}$. (2) Secondary flows were generally proportional to the velocity of the main flow. The intensity of the secondary flow was about 25% as much as that in the axial direction. (3) Pressure distributions were effects of the oscillatory Dean number and respective region.

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References

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