Conventional Probes for the Relative Flow Measurement in a Turbomachinery Rotor Blade Passage

Sitaram, N.; Lakshminarayana, B.; Ravindranath, A.

doi:10.1115/1.3230735

Cited by 24 publications

(10 citation statements)

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“…Recent investigations [25] have shown that the turbulence intensity affects the calibration characteristics of multihole probes and suggested that the multihole probes should be calibrated at the same turbulence intensity of the flow to be measured. Sitaram et al [26] have discussed these and other sources of errors in the application of five-hole probes and they gave estimates of their magnitudes. Near the wall, the flow is modified due to the presence of the probe and the probe gives erroneous results.…”

Section: Comparison Of Measurements In a Calibration Ductmentioning

confidence: 99%

A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

Jangir

Sitaram

Gajanan

2014

International Journal of Rotating Machinery

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A miniature four-hole probe with a sensing area of 1.284 mm 2 to minimise the measurement errors due to the large pressure and velocity gradients that occur in highly three-dimensional turbomachinery flows is designed, fabricated, calibrated, and validated. The probe has good spatial resolution in two directions, thus minimising spatial and flow gradient errors. The probe is calibrated in an open jet calibration tunnel at a velocity of 50 m/s in yaw and pitch angles range of ±40 degrees with an interval of 5 degrees. The calibration coefficients are defined, determined, and presented. Sensitivity coefficients are also calculated and presented. A lookup table method is used to determine the four unknown quantities, namely, total and static pressures and flow angles. The maximum absolute errors in yaw and pitch angles are 2.4 and 1.3 deg., respectively. The maximum absolute errors in total, static, and dynamic pressures are 3.4, 3.9, and 4.9% of the dynamic pressures, respectively. Measurements made with this probe, a conventional five-hole probe and a miniature Pitot probe across a calibration section, demonstrated that the errors due to gradient and surface proximity for this probe are considerably reduced compared to the five-hole probe.

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Section: Comparison Of Measurements In a Calibration Ductmentioning

confidence: 99%

A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

Jangir

Sitaram

Gajanan

2014

International Journal of Rotating Machinery

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“…Each of the pressure holes in the probe head was connected to a pressure transducer with high sensitivity. This probe was carefully calibrated in a calibration tunnel, where the pressures measured and the corresponding pitch or yaw angle was related through the relationships proposed by Sitaram et al (1981). The relationships were actually approximated by two-variable 4-th order polynomials whose coefficients were determined by the least square method.…”

Section: Instrumentation and Data Processingmentioning

confidence: 99%

Effects of Periodic Wake Passing Upon Aerodynamic Loss of a Turbine Cascade: Part I — Measurements of Wake-Affected Cascade Loss by Use of a Pneumatic Probe

Funazaki

Tetsuka

Tanuma

1999

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery

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This paper reports on an experimental investigation of aerodynamic loss of a low-speed linear turbine cascade which is subjected to periodic wakes shed from moving bars of the wake generator. In this case, parameters related to the wake, such as wake passing frequency (wake Strouhal number) or wake turbulence characteristics, are varied to see how these wake-related parameters affect the local loss distribution or mass-averaged loss coefficient of the turbine cascade. Free-stream turbulence intensity is changed by use of a turbulence grid. In Part I of this paper a focus is placed on the measurements by use of a pneumatic five-hole yawmeter, which provides time-averaged stagnation pressure distributions downstream of the moving bars as well as of the turbine cascade. Spanwise distributions of wake-affected exit flow angle are also measured. From this study it is found that the wake passing greatly affects not only the profile loss but secondary loss of the linear cascade. Noticeable change in exit flow angle is also identified.

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“…The main application of the FHP would be in location where it would be difficult to use a laser, such as the rotating frame of reference in a turbine or in geometrically difficult situations to reach flow zones. Sitaram et al have performed a detailed study on which type of probe to use within the rotating frame of a single stage compressor research rig at the Pennsylvania State University [11]. Town and Camci presented their early observations about using a subminiature Five-Hole Probe in an axial flow turbine rig in [12].…”

Section: Introductionmentioning

confidence: 99%

A Time Efficient Adaptive Gridding Approach and Improved Calibrations in Five-Hole Probe Measurements

Town

Camcı

2015

International Journal of Rotating Machinery

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Five-Hole Probes (FHP), being a dependable and accurate aerodynamic tool, are an excellent choice for measuring three-dimensional flow fields in turbomachinery. To improve spatial resolution, a subminiature FHP with a diameter of 1.68 mm is employed. High length to diameter ratio of the tubing and manual pitch and yaw calibration cause increased uncertainty. A new FHP calibrator is designed and built to reduce the uncertainty by precise, computer controlled movements and reduced calibration time. The calibrated FHP is then placed downstream of the nozzle guide vane (NGV) assembly of a low-speed, large-scale, axial flow turbine. The cold flow HP turbine stage contains 29 vanes and 36 blades. A fast and computer controllable traversing system is implemented using an adaptive grid method for the refinement of measurements in regions such as vane wake, secondary flows, and boundary layers. The current approach increases the possible number of measurement points in a two-hour period by 160%. Flow structures behind the NGV measurement plane are identified with high spatial resolution and reduced uncertainty. The automated pitch and yaw calibration and the adaptive grid approach introduced in this study are shown to be a highly effective way of measuring complex flow fields in the research turbine.

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Conventional Probes for the Relative Flow Measurement in a Turbomachinery Rotor Blade Passage

Cited by 24 publications

References 0 publications

A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

Effects of Periodic Wake Passing Upon Aerodynamic Loss of a Turbine Cascade: Part I — Measurements of Wake-Affected Cascade Loss by Use of a Pneumatic Probe

A Time Efficient Adaptive Gridding Approach and Improved Calibrations in Five-Hole Probe Measurements

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