• Title/Summary/Keyword: Five-Hole Probe

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Full angle range pressure coefficient maps of five-hole probe and new calibration coefficients (5공프로브의 전 각도 범위 압력계수 지도와 새로운 보정계수)

  • Kim, Jin-Gwon;Gang, Sin-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1437-1448
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    • 1997
  • Pressures of a five-hole probe were measured for a full range of yaw and pitch angles and complete pressure coefficient maps were obtained. Based on these maps, various features of five-hole probe pressures were revealed and new five-hole probe calibration coefficients were devised. The new calibration coefficients show non-diverging characteristics for any flow direction and one-to-one correspondence for a wide range of flow angles. These calibration coefficients expand the valid flow angle range of five-hole probe calibration by .+-.10 degrees and complement a critical defect of five-hole probe zone-division calibration method which has not been known yet. Moreover new non-diverging calibration coefficients have advantages in nulling methods, too.

Experimental investigation of flow parameters influencing the calibration of five-hole probes (5공프로우브의 보정에 영향을 주는 유동변수들에 대한 실험적 연구)

  • Lee, Sang-U;Yun, Tae-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.5
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    • pp.637-649
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    • 1997
  • Effects of cone angle, pressure-hole orientation and Reynolds number on the five-hole probe calibration have been investigated for eight large-scale conical five-hole probes, which have either perpendicular pressure holes or forward-facing pressure holes for the cone angles of 45 deg, 60 deg, 75 deg and 90.deg. Pitch and yaw angles are changed from -40 deg to +40 deg with an interval of 5 deg, respectively, when the probe Reynolds numbers are 1.77*10$^{4}$, 3.53*10$^{4}$ and 7.06*10$^{4}$. The result shows that larger cone angle results in more sensitive changes in the calibration coefficients. In the case that the cone angle is 45 deg, the pitch-angle and yaw-angle coefficients of the five-hole probe with the perpendicular pressure holes show a very different trend compared with those of the five-hole probe with the forward-facing pressure holes. On the other hand, when the cone angle is more than 60 deg, each calibration coefficient is nearly independent of the pressure-hole orientation. Additionally, the effects of the Reynolds number on the calibration coefficients are also reported in detail.

The Effect of Reynolds Number on the Calibration of a Five-Hole Probe at Low Reynolds Numbers (저 Reynolds 수 영역에서 Reynolds 수가 5공 프로우브의 보정에 미치는 영향)

  • Lee, Sang Woo;Jun, Sang Dae
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.193-199
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    • 2000
  • The effects of Reynolds number on the non-nulling calibration of a cone-type five-hole probe in low-speed flows have been investigated at the Reynolds numbers of $2.04{\times}10^3,\;4.09{\times}10^3$, and $6.13{\times}10^3$. The calibration is conducted at the pitch and yaw angles in ranges between -35 degrees and 35 degrees with an angle interval of 5 degrees. The result shows that each calibration coefficient, in general, is a function of the pitch and yaw angles, so that the pre-existing calibration data in a nulling mode are not enough in accounting for the full non-nulling calibration characteristics. Due to the interference of the probe stem, the calibration coefficients have more Reynolds number sensitivity at positive pitch angles than at negative ones.

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

  • Choi, Jin-Yong;Cho, Lee-Sang;Cho, Jin-Soo;Won, Eu-Pil
    • Proceedings of the KSME Conference
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    • 2000.11b
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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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Development of five-hole probe nulling method reliable in complex flow field (복잡한 유동장에서도 신뢰성 있는 5공프로브 널링기법의 개발)

  • Kim, Jin-Gwon;Gang, Sin-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1449-1457
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    • 1997
  • Since a non-nulling method of five-hole probes is valid only when the flow angle is within the calibrated angle range, it can not be used in a complex flow field. Full angle range pressure coefficient maps show that widely used nulling methods do not guarantee correct alignment of the probe with the flow direction in the unknown complex flow field. Zone decision method and features of zone map were studied by investigating the full angle range pressure coefficient maps. A reliable and efficient new nulling algorithm using zone decision by pressure ordering is proposed and verified. Since the zone decision method by pressure ordering can decide whether the flow is within the calibration angle range or not, it is useful in wide angle nonnulling methods, too.

A Study on the Five - hole Probe Calibration with Non-nulling Method (비영위법에 의한 5공 프로브의 교정에 관한 연구)

  • Jeong, Yang Beom;Sin, Yeong Ho;Park, Ho Dong
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.2
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    • pp.116-116
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw and total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

A Study on the Five-hole Probe Calibration with Non-nulling Method (비영위법에 의한 5공 프로브의 교정에 관한 연구)

  • 정양범;신영호;박호동
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.2
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    • pp.48-56
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw abd total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

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A Study on the Flow Characteristics in Axial Flow Rotors with Varying Tip Clearance (축류회전차에서 팁간극의 변화를 고려한 유동특성에 관한 연구)

  • 이명호
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.3
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    • pp.353-361
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    • 2002
  • The tip leakage flow passing through the clearance between rotor blade tip and casing shroud has been known to occupy an important portion of the rotor overall loss. In this study, flow characteristics in axial flow rotors with different tip clearances is investigated by experimental and numerical methods. The experimental study was carried out to measure static pressure and velocity profiles at the real rotating test rig. The axial flow rotors used for the experiments have ten blades and three different rotor diameter. The tip clearance heights are 1mm, 3mm, and 4.5mm. Measurements were done using spherical type five-hole probe by non-nulling method. The numerical study was carried out to calculate pressure distributions and velocity vectors at the same condition as the experiments in the flow fields of axial flow rotors using Phoenics code.

Design and Experimental Studies of Radial-Outflow Type Diagonal Flow Fan

  • Kinoue, Yoichi;Shiomi, Norimasa;Setoguchi, Toshiaki
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.1
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    • pp.18-24
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    • 2013
  • In order to apply the design method of diagonal flow fan based on axial flow design to the design of radial-outflow type diagonal flow fan which has lower specific speed of 600-700 [$min^{-1}$, $m^3/min$, m], radial-outflow type diagonal flow fan which specific speed was 670 [$min^{-1}$, $m^3/min$, m] was designed by a quasi three-dimensional design method. Experimental investigations were conducted by fan characteristics test, flow surveys by a five-hole probe and a hot wire probe. Fan characteristics test agreed well with the design values. In the flow survey at rotor outlet, the characteristic region was observed. Two flow phenomena are considered as the cause of the characteristic region, one is tip leakage vortex near rotor tip and another is pressure surface separation on the rotor blade.

Reynolds Number Effects on the Non-Nulling Calibration of a Cone-Type Five-Hole Probe for Turbomachinery Applications

  • Lee, Sang-Woo;Jun, Sang-Bae
    • Journal of Mechanical Science and Technology
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    • v.19 no.8
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    • pp.1632-1648
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    • 2005
  • The effects of Reynolds number on the non-nulling calibration of a typical cone-type five-hole probe have been investigated for the representative Reynolds numbers in turbomachinery. The pitch and yaw angles are changed from - 35 degrees to 35 degrees with an angle interval of 5 degrees at six probe Reynolds numbers in range between $6.60{\times}10^3\;and\;3.17{\times}10^4$. The result shows that not only each calibration coefficient itself but also its Reynolds number dependency is affected significantly by the pitch and yaw angles. The Reynolds-number effects on the pitch- and yaw-angle coefficients are noticeable when the absolute values of the pitch and yaw angles are smaller than 20 degrees. The static-pressure coefficient is sensitive to the Reynolds number nearly all over the pitch- and yaw-angle range. The Reynolds-number effect on the total-pressure coefficient is found remarkable when the absolute values of the pitch and yaw angles are larger than 20 degrees. Through a typical non-nulling reduction procedure, actual reduced values of the pitch and yaw angles, static and total pressures, and velocity magnitude at each Reynolds number are obtained by employing the calibration coefficients at the highest Reynolds number ($Re=3.17{\times}10^4$) as input reference calibration data. As a result, it is found that each reduced value has its own unique trend depending on the pitch and yaw angles. Its general tendency is related closely to the variation of the corresponding calibration coefficient with the Reynolds number. Among the reduced values, the reduced total pressure suffers the most considerable deviation from the measured one and its dependency upon the pitch and yaw angles is most noticeable. In this study, the root-mean-square data as well as the upper and lower bounds of the reduced values are reported as a function of the Reynolds number. These data would be very useful in the estimation of the Reynolds-number effects on the non-nulling calibration.