Time-Resolved Particle Image Velocimetry (PIV) Measurements in a Radial Diffuser Pump

2009 ◽  
Author(s):  
Jianjun Feng ◽  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Time Resolved ◽  
Piv Measurements ◽  
Part Load ◽  
Channel Characteristic ◽  
Image Velocimetry ◽  
Pump Stage ◽  
Low Specific Speed ◽  
Load Conditions

The truly time-variant unsteady flow in a low specific speed radial diffuser pump stage has been investigated by time-resolved Particle Image Velocimetry (PIV) measurements. The measurements are conducted at the midspan of the blades for the design condition and also for some severe part-load conditions. The instantaneous flow fields among different impeller channels are analyzed and compared in detail, and more attention has been paid to flow separations at part-load conditions. The analysis of the measured results shows that the flow separations at two adjacent impeller channels are quite different at some part-load conditions. The separations generally exhibit a two-channel characteristic.

Influence of the Blade Geometry on Flow Instabilities in a Radial Pump Elucidated by Time-Resolved Particle-Image Velocimetry

2007 ◽  
Author(s):  
Nico Krause ◽  
Eleme´r Pap ◽  
Dominique The´venin
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Load Flow ◽  
Rotating Stall ◽  
Flow Instabilities ◽  
Impeller Blade ◽  
Time Resolved ◽  
Part Load ◽  
Image Velocimetry ◽  
Radial Pump

Radial pumps are used in a variety of applications. In many cases the pump operates under part-load flow conditions and the inflow condition differs from the dimensioning, optimal point, ultimately leading to flow instabilities. In this paper the influence of three different impeller blade designs are presented under stall conditions. All the impeller blades are designed for the same pressure rise over the impeller but using different concepts. The pump characteristic curves clearly show the changes concerning energy transmission and losses. Time-Resolved Particle-Image Velocimetry (TR-PIV) is used to investigate the onset and development of rotating stall within the centrifugal pump under part-load conditions. These measurements lead to detailed instantaneous velocity distributions during rotating stall. Fast-Fourier-Transformation (FFT) is finally carried out on the series of instantaneous measured flow fields to identify characteristic flow frequencies. The onset of rotating stall is observed for different part-load flow-rates for the three impellers under investigation.

Experimental and Numerical Analysis of the Cavitating Part Load Vortex Dynamics of Low-Head Hydraulic Turbines

2011 ◽  
Author(s):  
Se´bastien Houde ◽  
Monica S. Iliescu ◽  
Richard Fraser ◽  
Se´bastien Lemay ◽  
Gabriel D. Ciocan ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Draft Tube ◽  
Experimental Methodology ◽  
Flow Measurements ◽  
Measured Velocity ◽  
Piv Measurements ◽  
Vortex Rope ◽  
Part Load ◽  
Image Velocimetry

The draft tube flow is a two-sided challenge for the operation of a hydraulic turbine. On one side, it is an important component for the performance of low to medium head turbines, where it can provide up to 40% of the extracted energy from the flow. On the other side, being a diffuser with a complex vorticity distribution at the inlet, vortex breakdown instability can occur at part load and generate a corkscrewed precessing vortex that can be associated with cavitation. The cavitating vortex rope, may generate undesired power output fluctuation and/or structural vibration. Therefore, draft tubes are much studied components but hard to tackle both numerically and experimentally. Within the framework of the AxialT project, the flow in the draft tube of a propeller turbine model operating at part load was studied using a combination of two-phase Particle Image Velocimetry (PIV) measurements and Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations. The paper main focus is on the experimental methodology and results. It explains how Particle Image Velocimetry measurements were implemented, validated and post-treated to provide flow measurements in the draft tube cone at part load in the cavitating and non-cavitating regimes. It also describes various image processing techniques used to extract the velocity field around the cavitating vortex rope and to estimate the location of the water-vapour interface of the cavitating region. In the spirit of feeding experimental data to numerical simulations, an analysis of measured velocity profiles just under the runner is presented. Comparison between PIV measurements and preliminary URANS simulations is also illustrated.

scholarly journals Time-resolved particle image velocimetry measurements of the turbulent Richtmyer–Meshkov instability

2021 ◽  
Vol 917 ◽  
Author(s):  
Everest G. Sewell ◽  
Kevin J. Ferguson ◽  
Vitaliy V. Krivets ◽  
Jeffrey W. Jacobs
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Time Resolved ◽  
Image Velocimetry

Abstract

Unveiling the Flow Behavior Inside GDI Engine Cylinder Using High-Speed Time-Resolved Particle Image Velocimetry and CFD Simulation

2021 ◽  
Author(s):  
Mohammed El Adawy ◽  
Morgan Heikal ◽  
bin Abd. Aziz Abd. Rashid
Keyword(s):  
Particle Image Velocimetry ◽  
High Speed ◽  
Particle Image ◽  
Cfd Simulation ◽  
Injection Pressure ◽  
Valve Lift ◽  
Fuel Spray ◽  
Time Resolved ◽  
Image Velocimetry ◽  
Spray Plume

Abstract RICARDO-VECTIS CFD simulation of the in-cylinder air flow was first validated with those of the experimental results from high-speed particle image velocimetry (PIV) measurements taking cognisant of the mid-cylinder tumble plane. Furthermore, high-speed fuel spray measurements were carried out simultaneously with the intake-generated tumble motion at high valve lift using high-speed time-resolved PIV to chronicle the spatial and time-based development of air/fuel mixture. The effect of injection pressure(32.5 and 35.0 MPa) and pressure variation across the air intake valves(150, 300 and 450 mmH2O) on the interaction process were investigated at valve lift 10 mm where the tumble vortex was fully developed and filled the whole cylinder under steady-state conditions. The PIV results illustrated that the intake generated-tumble motion had a substantial impact on the fuel spray distortion and dispersion inside the cylinder. During the onset of the injection process the tumble motion diverted the spray plume slightly towards the exhaust side before it followed completely the tumble vortex. The fuel spray plume required 7.2 ms, 6.2 ms and 5.9 ms to totally follow the in-cylinder air motion for pressure differences 150, 300 and 450 mmH2O, respectively. Despite, the spray momentum was the same for the same injection pressure, the magnitude of kinetic energy was different for different cases of pressure differences and subsequently the in-cylinder motion strength.

Investigation of Film Cooling Using Time-Resolved Stereo Particle Image Velocimetry

2020 ◽  
Author(s):  
Katharina Stichling ◽  
Maximilian Elfner ◽  
Hans-Jörg Bauer
Keyword(s):  
Particle Image Velocimetry ◽  
Film Cooling ◽  
Particle Image ◽  
Density Ratio ◽  
Test Rig ◽  
Time Resolved ◽  
Hot Gas ◽  
Image Velocimetry ◽  
Stereo Particle Image Velocimetry ◽  
Cooling Air

Abstract In the present study an existing test rig at the Institute of Thermal Turbomachinery (ITS), Karlsruhe Institute of Technology (KIT) designed for generic film cooling studies is adopted to accommodate time resolved stereoscopic particle image velocimetry measurements. Through a similarity analysis the test rig geometry is scaled by a factor of about 20. Operating conditions of hot gas and cooling air inlet and exit can be imposed that are compliant with realistic engine conditions including density ratio. The cooling air is supplied by a parallel-to-hot gas coolant flow-configuration with a coolant Reynolds number of 30,000. Time-resolved and time-averaged stereo particle image velocimetry data for a film cooling flow at high density ratio and a range of blowing ratios is presented in this study. The investigated film cooling hole constitutes a 10°-10°-10° laidback fan-shaped hole with a wide spacing of P/D = 8 to insure the absence of jet interaction. The inclination angle amounts to 35°. The time-resolved data indicates transient behaviour of the film cooling jet.

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