scholarly journals Laser Doppler Velocimetry Characterization of Unsteady Vaned Diffuser Flow in a Centrifugal Compressor

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
William J. Gooding ◽  
John C. Fabian ◽  
Nicole L. Key
Keyword(s):  
Centrifugal Compressor ◽  
Laser Doppler Velocimetry ◽  
High Speed ◽  
Pressure Rise ◽  
Laser Doppler ◽  
Wake Flow ◽  
Quality Data ◽  
Doppler Velocimetry ◽  
Design Development ◽  
Complex Flow

Abstract Modern turbomachinery faces increased performance demands in terms of efficiency, compactness, and pressure-rise. Advancements in computational technology have allowed numerical methods to become the backbone of design development efforts. However, the unique complexities of centrifugal compressor flow-fields pose difficult computational problems. As such, advanced experimental methods must be used to obtain high-quality data sets to further inform, improve, and validate computational methods in complex flow regimes. A recent experimental work on a high-speed centrifugal compressor has provided detailed, unsteady, three-component velocity data using laser Doppler velocimetry. A passage vortex is present, and its nascent tied to the increased incidence at mid-span associated with impeller wake flow. This vortex begins in the hub-pressure side corner and grows to fill the passage and become temporally stable. The vortex development is unsteady in nature, and the unsteady effects persist 40% downstream of the throat. Distinct jet and wake flow patterns from the impeller also do not agglomerate until 40% downstream of the throat. Additionally, the critical impact of the unsteady flow development on the time-averaged flow-field is explained.

LDV Characterization of Unsteady Vaned Diffuser Flow in a Centrifugal Compressor

2019 ◽  
Author(s):  
William J. Gooding ◽  
John C. Fabian ◽  
Nicole L. Key
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Rise ◽  
Wake Flow ◽  
Design Development ◽  
Complex Flow ◽  
Vaned Diffuser ◽  
Diffuser Flow ◽  
Component Velocity ◽  
Unsteady Effects

Abstract Modern turbomachinery faces increased performance demands in terms of efficiency, compactness, and pressure-rise. Advancements in computational technology have allowed numerical methods to become the backbone of design development efforts. However, the unique complexities of centrifugal compressor flow-fields pose difficult computational problems. As such, advanced experimental methods must be used to obtain high-quality datasets to further inform, improve, and validate computational methods in complex flow regimes. Recent experimental work on a high-speed centrifugal compressor has provided detailed, unsteady, three-component velocity data using Laser Doppler Velocimetry. A passage vortex is present and its nascent tied to the increased incidence at mid-span associated with impeller wake flow. This vortex begins in the hub-pressure side corner and grows to fill the passage and become temporally stable. The vortex development is unsteady in nature and the unsteady effects persist 40% downstream of the throat. Distinct jet and wake flow patterns from the impeller also do not agglomerate until 40% downstream of the throat. Additionally, the critical impact of the unsteady flow development on the time-averaged flow-field is explained.

Experimental Investigation of Water Jet Orifice Efficiency by a Novel Laser Doppler Velocimetry Technique

2006 ◽  
Author(s):  
Massimiliano Annoni ◽  
Loredana Cristaldi ◽  
Michele Norgia ◽  
Cesare Svelto
Keyword(s):  
Laser Doppler Velocimetry ◽  
High Speed ◽  
Dynamic Range ◽  
Water Jet ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Measured Velocity ◽  
Range Resolution ◽  
Cutting Head ◽  
Experimental Trials

The problem of efficiency evaluation of water jet nozzles has been dealt in the present work and a novel Laser Doppler Velocimetry (LDV) technique has been proposed in order to acquire high-speed water velocity at the exit of the cutting head nozzles. A standard LDV technique has been implemented for the first experimental trials with the aim of applying the theoretical approach to measured velocity values. A novel LDV technique has been proposed outlying of the critical aspects to be taken into account for future developments and improvements in measurement dynamic range, resolution, and accuracy.

scholarly journals Leveraging LDV techniques for the investigation of unsteady turbomachinery flows

2019 ◽  
Vol 123 (1270) ◽  
pp. 1919-1937 ◽  
Author(s):  
W. J. Gooding ◽  
N. L. Key
Keyword(s):  
Laser Doppler Velocimetry ◽  
High Speed ◽  
Noise Removal ◽  
Secondary Flows ◽  
Laser Doppler ◽  
Seed Particle ◽  
Doppler Velocimetry ◽  
Noise Sources ◽  
Flow Features ◽  
Narrowband Noise

ABSTRACTSteps required for proper acquisition and processing of laser Doppler velocimetry data for turbomachinery research applications are addressed. Turbomachinery applications are difficult due to the small internal passages, high-frequency fluctuations, large turbulence intensities, and strong secondary flows resulting in low overall signal-to-noise ratios and narrowband noise sources that cannot be removed by simple band-pass filters. Special aspects that must be considered for successful and accurate laser Doppler velocimetry studies to be conducted in turbomachinery are discussed. Specifically, the design of the measurement volume size, reflection mitigation, engineering of seed particle size and injection schema, and alignment of the traverse mechanism are addressed in terms of their importance (from literature sources) and the solutions implemented by the authors. These techniques have been applied to successfully obtain three-component, unsteady velocity data in a high-speed centrifugal compressor for aeroengine application. Processing techniques are also presented including a novel mixture-model-based statistical method for narrowband noise isolation developed by the authors. The method, validation steps, and example results are presented, showing the successful rejection of noise with high accuracy, a low failure rate, and a significant reduction in required manual inspection. This newly developed method elucidated flow features that were not clear prior to the noise removal.

Experimental and Numerical Investigation of an Aero-Engine Centrifugal Compressor

2009 ◽  
Author(s):  
Jason A. Bourgeois ◽  
Robert J. Martinuzzi ◽  
Douglas Roberts ◽  
Eric Savory ◽  
Chao Zhang
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Laser Doppler Velocimetry ◽  
Turbulence Modeling ◽  
Doppler Velocimetry ◽  
Complex Flow ◽  
Aero Engine ◽  
Simulation Results ◽  
Typical Design ◽  
Good Agreement

The complex flow field in turbomachinery poses numerous challenges for turbulence modeling. Herein, results of Laser Doppler Velocimetry (LDV) measurements of a full-scale aeroengine centrifugal compresser are used to validate typical design simulation results using a mixing plane and the k-ε, SST, or RSM-SSG turbulence closure models. Generally good agreement between simulation results and LDV measurements was found. The largest discrepancies were found in the near-wall regions: the predicted boundary layers were thicker and the flow more diffusive than measured. Important differences between the simulation results using different closures are discussed.

Aspects of Design and Manufacture of a Three-Dimensional Fibre Optic Laser Doppler Probe Head

2013 ◽  
Vol 397-400 ◽  
pp. 103-113 ◽  
Author(s):  
Noor A. Ahmed
Keyword(s):  
Flow Field ◽  
Laser Doppler Velocimetry ◽  
Three Dimensional ◽  
Laser Doppler ◽  
Doppler Velocimetry ◽  
Fibre Optic ◽  
Complex Flow ◽  
Doppler Probe ◽  
Dimensional Measurements ◽  
Probe Head

Laser Doppler Velocimetry is an important flow diagnostic methodology used in modern day fluid flow investigations. The present paper describes the design and manufacturing aspects of a novel fibre optic LASER Doppler probe head intended for three dimensional measurements in a complex flow field. The paper particularly concentrates on the tight tolerances required of the various components associated with the probe head to achieve the desired measurement volume. Keywords: Fibre Optic, Laser Doppler, Velocimetry, three-dimensional, complex flow field

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