Experimental Investigation of Unsteady Flow Field in the Tip Region of an Axial Compressor Rotor Passage at Near Stall Condition With Stereoscopic Particle Image Velocimetry

2004 ◽  
Vol 126 (3) ◽  
pp. 360-374 ◽  
Author(s):  
Baojie Liu ◽  
Hongwei Wang ◽  
Huoxing Liu ◽  
Hongjun Yu ◽  
Haokang Jiang ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Large Scale ◽  
Particle Image ◽  
Light Sheet ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Section ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Image Velocimetry ◽  
Corner Vortex

Stereoscopic particle image velocimetry (SPIV) was applied to a large-scale low-speed compressor facility with the configuration of the two CCD cameras placed on each side of the light sheet to make the measurement of the vortices in the cross flow section possible and to avoid the disturbance from the light sheet containing periscope-type probe. Instantaneous velocity and vorticity distributions were successfully documented at the tip region of the rotor at near stall condition. The measurement results clearly revealed the generation and evolution of the tip leakage vortex. Comparing to design condition, the tip leakage vortex at near stall condition generates and breaks down earlier and interacts more violently with mainstream, which causes large blockage and much loss. Whether corner vortex exists or not is the primary difference between near stall and design condition. Differing from the leakage vortex, the corner vortex is composed of multiple vortices developed from the suction surface of the rotor blade. The key mechanism for the generation of the corner vortex is that the rotation of the rotor has different effect on the evolution of positive vortices and negative vortices, which makes the positive vortices dissipates faster than the negative ones, the vortices at the rotor exit therefore bear mainly negative vortices, which induces the fluids to rotate clockwise at the corner and forms the corner vortex.

Experimental Investigation of Unsteady Flow Field in the Tip Region of an Axial Compressor Rotor Passage at Near Stall Condition With SPIV

2003 ◽  
Author(s):  
Baojie Liu ◽  
Hongwei Wang ◽  
Huoxing Liu ◽  
Hongjun Yu ◽  
Haokang Jiang ◽  
...  
Keyword(s):  
Large Scale ◽  
Cross Flow ◽  
Axial Compressor ◽  
Light Sheet ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Section ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Corner Vortex

Stereoscopic Particle Image Velocimetry (SPIV) was applied to a large-scale low-speed compressor facility with the configuration of the two CCD cameras placed on each side of the light sheet to make the measurement of the vortices in the cross flow section possible and to avoid the disturbance from the light sheet containing periscope-type probe. Instantaneous velocity and vorticity distributions were successfully documented at the tip region of the rotor at near stall condition. The measurement results clearly revealed the generation and evolution of the tip leakage vortex. Comparing to design condition, the tip leakage vortex at near stall condition generates and breaks down earlier and interacts more violently with mainstream, which causes large blockage and much loss. Whether corner vortex exists or not is the primary difference between near stall and design condition. Differing from the leakage vortex, the corner vortex is composed of multiple vortices developed from the suction surface of the rotor blade. The key mechanism for the generation of the corner vortex is that the rotation of the rotor has different effect on the evolution of positive vortices and negative vortices, which makes the positive vortices dissipates faster than the negative ones, the vortices at the rotor exit therefore bear mainly negative vortices, which induces the fluids to rotate clockwise at the corner and forms the corner vortex.

Development and Testing of an Unmanned Aerial Vehicle for Large Scale Particle Image Velocimetry

2014 ◽  
Author(s):  
Christopher Pagano ◽  
Flavia Tauro ◽  
Salvatore Grimaldi ◽  
Maurizio Porfiri
Keyword(s):  
Particle Image Velocimetry ◽  
Large Scale ◽  
Field Experiments ◽  
Particle Image ◽  
Low Cost ◽  
Surface Flow ◽  
Natural Environments ◽  
Natural Stream ◽  
Image Velocimetry ◽  
Scale Particle

Large scale particle image velocimetry (LSPIV) is a nonintrusive environmental monitoring methodology that allows for continuous characterization of surface flows in natural catchments. Despite its promise, the implementation of LSPIV in natural environments is limited to areas accessible to human operators. In this work, we propose a novel experimental configuration that allows for unsupervised LSPIV over large water bodies. Specifically, we design, develop, and characterize a lightweight, low cost, and stable quadricopter hosting a digital acquisition system. An active gimbal maintains the camera lens orthogonal to the water surface, thus preventing severe image distortions. Field experiments are performed to characterize the vehicle and assess the feasibility of the approach. We demonstrate that the quadricopter can hover above an area of 1×1m2 for 4–5 minutes with a payload of 500g. Further, LSPIV measurements on a natural stream confirm that the methodology can be reliably used for surface flow studies.

scholarly journals A New Particle Image Velocimetry Technique for Turbomachinery Applications

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Sayantan Bhattacharya ◽  
Reid A. Berdanier ◽  
Pavlos P. Vlachos ◽  
Nicole L. Key
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Laser Sheet ◽  
Measurement Techniques ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Particle Image Velocimetry Technique ◽  
Optical Access ◽  
Tip Leakage ◽  
Image Velocimetry

Nonintrusive measurement techniques such as particle image velocimetry (PIV) are growing in both capability and utility for turbomachinery applications. However, the restrictive optical access afforded by multistage research compressors typically requires the use of a periscope probe to introduce the laser sheet for measurements in a rotor passage. This paper demonstrates the capability to perform three-dimensional PIV in a multistage compressor without the need for intrusive optical probes and requiring only line-of-sight optical access. The results collected from the embedded second stage of a three-stage axial compressor highlight the rotor tip leakage flow, and PIV measurements are qualitatively compared with high-frequency response piezoresistive pressure measurements to assess the tip leakage flow identification.

Investigations on Slug Flow in a Horizontal Pipe Using Stereoscopic Particle Image Velocimetry and CFD Simulation With Volume of Fluid Method

2012 ◽  
Author(s):  
Marek Czapp ◽  
Matthias Utschick ◽  
Johannes Rutzmoser ◽  
Thomas Sattelmayer
Keyword(s):  
Particle Image Velocimetry ◽  
Slug Flow ◽  
Particle Image ◽  
Volume Of Fluid ◽  
Stereoscopic Particle Image Velocimetry ◽  
Horizontal Pipe ◽  
Pressurized Water ◽  
Cooling Circuit ◽  
Image Velocimetry ◽  
Slug Flows

Investigations on gas-liquid flows in horizontal pipes are of immanent importance for Reactor Safety Research. In case of a breakage of the main cooling circuit of a Pressurized Water Reactor (PWR), the pressure losses of the gas-liquid flow significantly govern the loss of coolant rate. The flow regime is largely determined by liquid and gas superficial velocities and contains slug flow that causes high-pressure pulsations to the infrastructure of the main cooling circuit. Experimental and numerical investigations on adiabatic slug flow of a water-air system were carried out in a horizontal pipe of about 10 m length and 54 mm diameter at atmospheric pressure and room temperature. Stereoscopic high-speed Particle Image Velocimetry in combination with Laser Induced Fluorescence was successfully applied on round pipe geometry to determine instantaneous three-dimensional water velocity fields of slug flows. After grid independence studies, numerical simulations were run with the open-source CFD program OpenFOAM. The solver uses the VOF method (Volume of Fluid) with phase-fraction interface capturing approach based on interface compression. It provides mesh refinement at the interfacial area to improve resolution of the interface between the two phases. Furthermore, standard k-ε turbulence model was applied in an unsteady Reynolds averaged Navier Stokes (URANS) model to resolve self-induced slug formation. The aim of this work is to present the feasibility of both relatively novel possibilities of determining two-phase slug flows in pipes. Experimental and numerical results allow the comparison of the slug initiation and expansion process with respect to their axial velocities and cross-sectional void fractions.

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