Investigations of Particle Velocities in a Slurry Pump Using PIV: Part 1, The Tongue and Adjacent Channel Flow

2004 ◽  
Vol 126 (4) ◽  
pp. 271-278 ◽  
Author(s):  
Jaikrishnan R. Kadambi ◽  
Pathom Charoenngam ◽  
Amirthaganesh Subramanian ◽  
Mark P. Wernet ◽  
John M. Sankovic ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Particle Image ◽  
Pressure Side ◽  
Pipeline Transport ◽  
Particle Image Velocimetry Technique ◽  
Pump Speed ◽  
Image Velocimetry ◽  
Adjacent Channel ◽  
Particle Velocities ◽  
Solid Liquid

Transport of solid-liquid slurries in pipeline transport over short and medium distances is very important in many industries, including mining related processes. The particle image velocimetry technique was successfully utilized to investigate the velocities and kinetic energy fluctuations of slurry particles at the tongue region of an optically-clear centrifugal pump. The experiments were conducted using 500 micron glass beads at volumetric concentrations of 2.5% and 5% and at pump speeds of 725 rpm and 1000 rpm. The fluctuation kinetic energy increased approximately 200% to 500% as the pump speed was increased from 725 rpm to 1000 rpm. The directional impingement mechanism is more significant at the pressure side of the blade, tongue and the casing. This mechanism becomes more important as the speed increases. This suggests that the impeller, tongue and the casing of the slurry pump can wear out quickly, especially with an increase in speed. In this paper the emphasis is on the tongue region. The random impingement mechanism caused by the fluctuation kinetic energy of the solids can play an important role on the erosion of the tongue area.

PIV Investigations of Particle Velocities in the Tongue Region of a Slurry Pump

2002 ◽  
Author(s):  
P. Charoenngam ◽  
A. Subramanian ◽  
J. R. Kadambi ◽  
M. Wernet ◽  
J. Sankovic ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Kinetic Energy ◽  
Particle Image ◽  
Pressure Side ◽  
Pipeline Transport ◽  
Particle Image Velocimetry Technique ◽  
Pump Speed ◽  
Image Velocimetry ◽  
Particle Velocities ◽  
Solid Liquid

Transport of solid-liquid slurries in pipeline transport over short and medium distances is very important in many industries, including mining related processes. The particle image velocimetry technique was successfully utilized to investigate the velocities and kinetic energy fluctuations of slurry particles at the tongue region of an optically-clear centrifugal pump. The experiments were conducted using 500 micron glass beads at volumetric concentrations of 2.5% and 5% at pump speeds of 725 and 1000 rpm. The fluctuation kinetic energy increased approximately 200% to 500% as the pump speed was increased from 725 rpm to 1000 rpm. The directional impingement mechanism is more significant at the pressure side of the blade, tongue and the casing. This mechanism becomes more important as the speed increases. This suggests that the impeller, tongue and the casing of the slurry pump can wear out quickly, especially with an increase in speed. In this paper the emphasis is on the tongue region. The random impingement mechanism caused by the fluctuation kinetic energy of the solids can play an important role on the erosion of the tongue area.

Particulate Velocity Measurements in the Intra-Blade Passages of a Centrifugal Slurry Pump

2003 ◽  
Author(s):  
J. R. Kadambi ◽  
M. Mehta ◽  
P. Charoenngam ◽  
M. P. Wernet ◽  
J. Sankovic ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Suction Side ◽  
Pressure Side ◽  
Pump Speed ◽  
Frictional Wear ◽  
Maximum Fluctuation ◽  
Blade Tip ◽  
Iodide Solution ◽  
Particle Velocities ◽  
Slurry Transport

The purpose of a slurry pump is to transport solids in a mixture called a slurry. It is a critical component of the slurry transport system in many industrial and mining related processes. In this investigation, Particle Image Velocimetry (PIV) was successfully utilized for measuring the particle velocities in the impeller intra-blade passages of an optically clear centrifugal pump (a transparent casing and a transparent three-blade impeller). An optically clear slurry consisting of sodium-iodide solution and 500 μm spherical glass particles was used. The experiments were conducted at speeds of 725 and 1000 rpm with volumetric concentrations of 2.5% and 5% respectively. In the impeller passage region, the highest particle velocities are generated on the suction side of the blade and in the blade trailing edge region as the blade sweeps through. However, these particle velocities are slower than the circumferential velocity of the blade tip. The particle fluctuation kinetic energy increased approximately 200% to 500% as the pump speed was increased from 725 rpm to 1000 rpm. The maximum fluctuation kinetic energy occurred on the suction side of the blade. The directional impingement mechanism is more significant at the pressure side of the blade. This mechanism becomes more pronounced as the speed increases. The random impingement mechanism caused by the fluctuation kinetic energy of the solids can play an important role on the blade surface (pressure and suction sides) and the casing wall erosion. Frictional wear mechanisms can be caused by the particles that do not stay suspended in the flow and accumulate into sliding beds along the pressure side of the blade. PIV measurements in the slurry pump model can add significantly to the understanding of the flow through the pump.

Analysis of local velocity gradients in rapid mixer using particle image velocimetry technique

2002 ◽  
Vol 2 (5-6) ◽  
pp. 47-55
Author(s):  
N.-S. Park ◽  
H. Park
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Velocity Fields ◽  
Local Velocity ◽  
Mixing Condition ◽  
Particle Image Velocimetry Technique ◽  
Velocity Gradients ◽  
Image Velocimetry ◽  
Current Design ◽  
G Value

Recognizing the significance of factual velocity fields in a rapid mixer, this study focuses on analyzing local velocity gradients in various mixer geometries with particle image velocimetry (PIV) and comparing the results of the analysis with the conventional G-value, for reviewing the roles of G-value in the current design and operation practices. The results of this study clearly show that many arguments and doubts are possible about the scientific correctness of G-value, and its current use. This is because the G-value attempts to represent the turbulent and complicated factual velocity field in a jar. Also, the results suggest that it is still a good index for representing some aspects of mixing condition, at least, mixing intensity. However, it cannot represent the distribution of velocity gradients in a jar, which is an important factor for mixing. This study as a result suggests developing another index for representing the distribution to be used with the G-value.

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.

Abstract 14952: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ahmad Falahatpisheh ◽  
Arash Kheradvar
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Contrast Echocardiography ◽  
Ultrasound Contrast Agent ◽  
Three Dimensions ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Two Dimensional ◽  
Particle Image Velocimetry Technique ◽  
Image Velocimetry

Introduction: The two-dimensional (2D) echocardiographic particle image velocimetry technique that was introduced in 2010 received much attention in clinical cardiology. Cardiac flow visualization based on contrast echocardiography results in images with high temporal resolution that are obtainable at relatively low cost. This makes it an ideal diagnostic and follow-up tool for routine clinical use. However, cardiac flow in a cardiac cycle is multidirectional with a tendency to spin in three dimensions rather than two-dimensional curl. Here, for the first time, we introduce a volumetric echocardiographic particle image velocimetry technique that robustly acquires the flow in three spatial dimensions and in time: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV). Methods: V-Echo-PIV technique utilizes matrix array 3D ultrasound probes to capture the flow seeded with an ultrasound contrast agent (Definity). For this feasibility study, we used a pulse duplicator with a silicone ventricular sac along with bioprosthetic heart valves at the inlet and outlet. GE Vivid E9 system with an Active Matrix 4D Volume Phased Array probe at 30 Hz was used to capture the flow data (Figure 1). Results: The 3D particle field was obtained with excellent spatial resolution without significant noise (Figure 1). 3D velocity field was successfully captured for multiple cardiac cycles. Flow features are shown in Figure 2 where the velocity vectors in two selected slices and some streamlines in 3D space are depicted. Conclusions: We report successful completion of the feasibility studies for volumetric echocardiographic PIV in an LV phantom. The small-scale features of flow in the LV phantom were revealed by this technique. Validation and human studies are currently in progress.

PIV Investigation of an Open Channel Flow Over a Forward Facing Step

2007 ◽  
Author(s):  
M. K. Shah ◽  
M. F. Tachie
Keyword(s):  
Open Channel ◽  
Particle Image ◽  
Open Channel Flow ◽  
Reynolds Stresses ◽  
Velocity Measurements ◽  
Particle Image Velocimetry Technique ◽  
Mean Velocity ◽  
Freestream Velocity ◽  
Image Velocimetry ◽  
Forward Facing Step

The characteristics of an open channel turbulent flow over a forward facing step (FFS) are investigated in the present study. Two step heights, h = 6 and 9 mm, at Reynolds number, Reh, (based on the approach freestream velocity, U0, and step height, h) of 1900 and 2800 respectively were studied. Particle image velocimetry technique (PIV) was used to obtain detailed velocity measurements upstream of the FFS, in the reattachment region (x/h = 0, 1, 2) and in the redevelopment region (x/h = 4, 10, 15 and 50). The boundary layer integral parameters, mean velocity profiles and Reynolds stresses obtained in the reattachment and redevelopment region are used to document some of the salient features of the flow.

The velocity field under breaking waves: coherent structures and turbulence

2002 ◽  
Vol 454 ◽  
pp. 203-233 ◽  
Author(s):  
W. KENDALL MELVILLE ◽  
FABRICE VERON ◽  
CHRISTOPHER J. WHITE
Keyword(s):  
Velocity Field ◽  
Kinetic Energy ◽  
Reynolds Stress ◽  
Particle Image ◽  
Early Stage ◽  
Breaking Waves ◽  
Video Frame ◽  
Turbulent Kinetic Energy Budget ◽  
Image Velocimetry ◽  
Coherent Vortex

Digital particle image velocimetry (DPIV) measurements of the velocity field under breaking waves in the laboratory are presented. The region of turbulent fluid directly generated by breaking is too large to be imaged in one video frame and so an ensemble-averaged representation of the flow is built up from a mosaic of image frames. It is found that breaking generates at least one coherent vortex that slowly propagates downstream at a speed consistent with the velocity induced by its image in the free surface. Both the kinetic energy of the flow and the vorticity decay approximately as t−1. The Reynolds stress of the turbulence also decays as t−1 and is, within the accuracy of the measurements, everywhere negative, consistent with downward transport of streamwise momentum. Estimates of the mometum flux from waves to currents based on the measurements of the Reynolds stress are consistent with earlier estimates. The implications of the measurements for breaking in the field are discussed. Based on geometrical optics and wave action conservation, we suggest that the presence of the breaking-induced vortex provides an explanation for the suppression of short waves by breaking. Finally, in Appendices, estimates of the majority of the terms in the turbulent kinetic energy budget are presented at an early stage in the evolution of the turbulence, and comparisons with independent acoustical measurements of breaking are presented.

Experimental Investigation of Unsteady Flow Field Within a Two Stage Axial Turbomachine Using Particle Image Velocimetry

2002 ◽  
Author(s):  
Oguz Uzol ◽  
Yi-Chih Chow ◽  
Joseph Katz ◽  
Charles Meneveau
Keyword(s):  
Particle Image Velocimetry ◽  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Particle Image ◽  
Energy Levels ◽  
Shear Stresses ◽  
Image Velocimetry ◽  
Entire Flow ◽  
The Difference

Detailed measurements of the flow field within the entire 2nd stage of a two stage axial turbomachine are performed using Particle Image Velocimetry. The experiments are performed in a facility that allows unobstructed view on the entire flow field, facilitated using transparent rotor and stator and a fluid that has the same optical index of refraction as the blades. The entire flow field is composed of a “lattice of wakes”, and the resulting wake-wake and wake-blade interactions cause major flow and turbulence non-uniformities. The paper presents data on the phase averaged velocity and turbulent kinetic energy distributions, as well as the average-passage velocity and deterministic stresses. The phase-dependent turbulence parameters are determined from the difference between instantaneous and the phase-averaged data. The distributions of average-passage flow field over the entire stage in both the stator and rotor frames of reference are calculated by averaging the phase-averaged data. The deterministic stresses are calculated from the difference between the phase-averaged and average-passage velocity distributions. Clearly, wake-wake and wake-blade interactions are the dominant contributors to generation of high deterministic stresses and tangential non-uniformities, in the rotor-stator gap, near the blades and in the wakes behind them. The turbulent kinetic energy levels are generally higher than the deterministic kinetic energy levels, whereas the shear stress levels are comparable, both in the rotor and stator frames of references. At certain locations the deterministic shear stresses are substantially higher than the turbulent shear stresses, such as close to the stator blade in the rotor frame of reference. The non-uniformities in the lateral velocity component due to the interaction of the rotor blade with the 1st stage rotor-stator wakes, result in 13% variations in the specific work input of the rotor. Thus, in spite of the relatively large blade row spacings in the present turbomachine, the non-uniformities in flow structure have significant effects on the overall performance of the system.

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