Investigation of Cross-Sectional Velocity Field Near the Inducer Plane of a Turbocharger Compressor Using 2D Particle Image Velocimetry

2019 ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Keith Miazgowicz ◽  
Todd Brewer ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Flow Field ◽  
Mass Flow ◽  
Particle Image ◽  
Tangential Velocity ◽  
Cross Sectional ◽  
Flow Rates ◽  
Blade Passage ◽  
Image Velocimetry

Abstract Understanding the velocity field at the inlet of an automotive turbocharger is critical in order to suppress the instabilities encountered by the compressor, extend its map and improve the impeller design. In the present study, two-dimensional particle image velocimetry experiments are carried out on a turbocharger compressor without any recirculating channel to investigate the planar flow structures on a cross-sectional plane right in front of the inducer at a rotational speed of 80 krpm. The objective of the study is to investigate the flow field in front of a compressor blade passage and quantify the velocity distributions along the blade span for different mass flow rates ranging from choke (77 g/s) to deep surge (13.6 g/s). It is observed that the flow field does not change substantially from choke to about 55 g/s, where flow reversal is known to start at this speed from earlier measurements. While the tangential velocity is less than 8 m/s, the radial velocity increases along the span to 17–20 m/s near the tip at high flow rates (55–77 g/s). As the mass flow rate is reduced below 55 g/s, the radial component starts decreasing and the tangential velocity increases rapidly. From about 5 m/s at 55 g/s, the tangential velocity at the blade tip exceeds 50 m/s at 50 g/s and reaches a maximum of about 135 m/s near surge. These time-averaged distributions are similar for different angular locations in front of the blade passage and do not exhibit any substantial azimuthal variation.

scholarly journals Simultaneous Measurement of Free Surface Elevation and Three-Component Velocity Field Around a Translating Surface-Piercing Foil

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
James Schock ◽  
Jason Dahl
Keyword(s):  
Particle Image Velocimetry ◽  
Free Surface ◽  
Velocity Field ◽  
Numerical Methods ◽  
Flow Field ◽  
Particle Image ◽  
Laser Sheet ◽  
Three Dimensional ◽  
Dynamic Mode ◽  
Image Velocimetry

Two methods are investigated to simultaneously obtain both three-dimensional (3D) velocity field and free surface elevations (FSEs) measurements near a surface piercing foil, while limiting the equipment. The combined velocity field and FSE measurements are obtained specifically for the validation of numerical methods requiring simultaneous field data and free surface measurements for a slender body shape. Both methods use stereo particle image velocimetry (SPIV) to measure three component velocities in the flow field and both methods use an off the shelf digital camera with a laser intersection line to measure FSEs. The first method is performed using a vertical laser sheet oriented parallel to the foil chord line. Through repetition of experiments with repositioning of the laser, a statistical representation of the three-dimensional flow field and surface elevations is obtained. The second method orients the vertical laser sheet such that the foil chord line is orthogonal to the laser sheet. A single experiment is performed with this method to measure the three-dimensional three component (3D3C) flow field and free surface, assuming steady flow conditions, such that the time dimension is used to expand the flow field in 3D space. The two methods are compared using dynamic mode decomposition and found to be comparable in the primary mode. Utilizing these methods produces results that are acceptable for use in numerical methods verification, at a fraction of the capital and computing cost associated with two plane or tomographic particle image velocimetry (PIV).

Investigation of Flow Field at the Inlet of a Turbocharger Compressor Using Digital Particle Image Velocimetry

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Kevin Tallio ◽  
Keith Miazgowicz ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Reversal ◽  
High Mass ◽  
Reversed Flow ◽  
Image Velocimetry

Abstract The flow field at the inlet of a turbocharger compressor has been studied through stereoscopic particle image velocimetry (SPIV) experiments under different operating conditions. It is found that the flow field is quite uniform at high mass flow rates; but as the mass flow rate is reduced, flow reversal from the impeller is observed as an annular ring at the periphery of the inlet duct. The inception of flow reversal is observed to occur in the mid-flow operating region, near peak efficiency, and corresponds to an incidence angle of about 15.5 deg at the inducer blade tips at all tested speeds. This reversed flow region is marked with high tangential velocity and rapid fluctuations. It grows in strength with reducing mass flow rate and imparts some of its angular momentum to the forward flow due to mixing. The penetration depth of the reversed flow upstream from the inducer plane is found to increase quadratically with decreasing flow rate.

Particle Image Velocimetry As Applied to Inlet Flow Field of a Turbocharger Compressor at Varying Rotational Speeds With Emphasis on Surge

2020 ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Keith Miazgowicz
Keyword(s):  
Flow Field ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Particle Image ◽  
Reversed Flow ◽  
Cross Sectional ◽  
Image Velocimetry ◽  
Compressor Map ◽  
Cross Sectional Average

Abstract Turbocharger surge remains an area of concern for the automotive industry as it limits the permissible operating range on the compressor map, while also adversely impacting the compressor’s pressure rise, efficiency, and acoustics. The present study uses Stereoscopic Particle Image Velocimetry (SPIV) to investigate the flow field at the inlet of an automotive turbocharger compressor without a recirculating channel. Experiments were carried out at four different speeds, including 80, 100, 120, and 140 krpm, which represent a substantial portion of the compressor map. The mass flow rates investigated ranged from choke to deep surge, thus spanning the entire mass flow regime at each rotational speed. The current work aims to characterize how the compressor inlet velocity field varies with rotational speed, with a specific emphasis on surge. The qualitative nature of the flow field (radial dependence of axial and tangential velocity profiles), over the choke to mild surge range, was observed to be nearly independent of rotational speed for comparable operating conditions (for example, comparison of mild surge at different rotational speeds). A quantitative comparison of the velocity profiles at the choke or mild surge operating points showed an increase in the velocity magnitudes with increasing rotational speed. The flow field at deep surge, however, was observed to change substantially from 80 krpm to 140 krpm. At 80 krpm, the character of the flow field at different times (at different points on the surge cycle) was observed to be similar: the core flow near the center of the duct was always directed into the impeller, whereas the reversed flow occupied an annular region near the periphery in nearly all time instances. However, as the rotational speed was increased to 140 krpm, the variation in the flow field at different instances within a deep surge cycle increased. At 140 krpm, the negative flow rate (where the cross-sectional average flow is directed out of the inducer back into the inlet duct) portion of the surge cycle was still similar to the overall surge flow field at 80 krpm, but over a substantial part of the positive flow rate (cross-sectional average flow is directed into the impeller) portion of the surge cycle, there was no sign of reversed flow within the visualization domain. As the rotational speed was increased, the surge loop (obtained by combining the PIV and pressure transducer data) extended over a wider portion of the compressor map with higher maximum (positive) and minimum (negative) flow rates, along with higher amplitude pressure fluctuations. The mean amplitude of mass flow rate and pressure ratio fluctuations at deep surge increased in nearly a quadratic fashion with rotational speed. The deep surge frequency did not change substantially over the range of rotational speeds examined in this study.

scholarly journals Automatic Particle Image Velocimetry Uncertainty Quantification

2010 ◽  
Author(s):  
Benjamin H. Timmins ◽  
Barton L. Smith ◽  
Pavlos P. Vlachos
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Flow Field ◽  
Uncertainty Quantification ◽  
Velocity Gradient ◽  
Particle Image ◽  
Particle Density ◽  
Particle Displacement ◽  
Particle Image Diameter ◽  
Image Velocimetry

A method to estimate the uncertainty of each vector in Particle Image Velocimetry measurements by estimating the parameters which contribute to errors in the computed velocity field is discussed. These parameters include particle image diameter, particle density, particle displacement, and velocity gradient. After PIV processing, our code “measures” these parameters and an estimate of the velocity uncertainty is made for each vector in the flow field.

A Digital Particle Image Velocimetry Investigation of Flow Field Instabilities of Axial-Flow Impellers

1997 ◽  
Vol 119 (3) ◽  
pp. 623-632 ◽  
Author(s):  
K. J. Myers ◽  
R. W. Ward ◽  
Andre´ Bakker
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
High Efficiency ◽  
Low Frequency ◽  
Axial Flow ◽  
Digital Particle Image Velocimetry ◽  
Blade Passage ◽  
Image Velocimetry ◽  
Pitched Blade Turbine

Digital particle image velocimetry (DPIV) has been used to examine the flow field in a vessel agitated by an axial-flow impeller in turbulent operation. Both a pitched-blade turbine and a high-efficiency impeller were studied. Time series analysis indicates that the flow field is not steady; rather, it is subject to transients with frequencies well below the blade passage frequency (periods ranging from 40 to over 300 impeller revolutions have been observed). This result has important implications for computational modeling because current descriptions of agitated vessels are based upon time-averaged flow fields with superimposed turbulence. This modeling approach may not accurately capture the mixing associated with the low-frequency phenomena observed in this study.

Particle Image Velocimetry Measurements of Tornado-Like Flow Field in Model WindEEE Dome

2014 ◽  
Author(s):  
Maryam Refan ◽  
Horia Hangan ◽  
Kamran Siddiqui
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Radial Velocity ◽  
Particle Image ◽  
Tangential Velocity ◽  
Scaled Model ◽  
Energy And Environment ◽  
Radial Profiles ◽  
Image Velocimetry ◽  
Wide Range

The flow field of tornado vortices simulated in the 1/11 scaled model of the Wind Engineering, Energy and Environment (WindEEE) Dome is characterized. Particle Image Velocimetry measurements were performed to investigate the flow dynamics for a wide range of Swirl ratios (0.12≤S≤1.29) and at various heights above the surface. It is shown that this simulator is capable of generating a wide variety of tornado like vortices ranging from a single-celled laminar vortex to a multi-celled turbulent vortex. Radial profiles of the tangential velocity demonstrated a clear variation in the experimental values with height at and after the touch-down of the breakdown bubble. Also, the comparison between experimental tangential velocities and the Rankine model estimations resulted in good agreement at only the upper levels (Z>0.35). Radial velocity values close to the surface rose as the swirl increased which is mainly due to the intensified tangential velocities in that region. In addition, variation of the radial velocity with height is more noticeable for higher swirls which can be explained by the flow regime being fully turbulent for S≥ 0.57.

Impact of Rotational Speed on Turbocharger Compressor Surge Through Particle Image Velocimetry1

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet ◽  
Keith Miazgowicz
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Rate ◽  
Rotational Speed ◽  
Particle Image ◽  
Reversed Flow ◽  
Cross Sectional ◽  
Average Flow ◽  
Image Velocimetry ◽  
Cross Sectional Average

Abstract Stereoscopic particle image velocimetry is used to characterize the variation of the turbocharger compressor inlet velocity field as a function of rotational speed, with an emphasis on surge. While the velocity magnitudes at choke or mild surge increased with rotational speed, the velocity profiles remained qualitatively similar. The variation in deep surge flow field with shaft speed, however, was more substantial. At 80 krpm, the overall flow field was comparable at different time instances (at different points on the surge cycle): the core flow near the duct center was always directed into the impeller, whereas reversed flow occupied an annular region near the periphery in nearly all time instances. However, at 140 krpm, while the negative flow rate (cross-sectional average flow is directed out of the inducer back into the inlet duct) portion of the surge cycle was still similar to the overall surge flow field at 80 krpm, over a substantial part of the positive flow rate (cross-sectional average flow is directed into the impeller) portion of the surge cycle, there was no sign of reversed flow within the visualization domain. As the rotational speed was increased, the surge loop (obtained by combining the particle image velocimetry (PIV) and pressure transducer data) extended over a wider portion of the compressor map with higher maximum (positive) and minimum (negative) flow rates, along with higher amplitude pressure fluctuations. The mean amplitude of mass flow rate and pressure ratio fluctuations at deep surge increased in nearly a quadratic fashion with rotational speed.

Discussion the Method of the Flocculation Flow Field Measurement by PIV

2014 ◽  
Vol 496-500 ◽  
pp. 1101-1104
Author(s):  
Jun Feng Gao
Keyword(s):  
Particle Image Velocimetry ◽  
Velocity Field ◽  
Flow Field ◽  
Particle Image ◽  
Seed Particle ◽  
Seed Particles ◽  
Image Velocimetry ◽  
Flocculation Process ◽  
Flow Field Measurement ◽  
Polyaluminium Chloride

Particle image velocimetry was applied to measure the velocity field during the flocculation process under the conditions that the flocs compounded with kaolin and polyaluminium chloride were used as seed particles without any other special seed particle during the flocculation process. The results indicated that the flocs formed in the flocculation process can be used as seed particles to measure the instantaneous velocity maps of the flow field with good performance during the flocculation process by PIV. At the same time, the experimental results proved that PIV can be exploited as a useful tool in the synchronism measurement the velocity field and flocculation processes.

Turbulence Measurements at the Inlet of an Automotive Turbocharger Compressor using Stereoscopic Particle Image Velocimetry

2021 ◽  
pp. 1-50
Author(s):  
Deb Banerjee ◽  
Rick Dehner ◽  
Ahmet Selamet
Keyword(s):  
Particle Image Velocimetry ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Mass Flow ◽  
Particle Image ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Rates ◽  
Image Velocimetry ◽  
Compressor Inlet ◽  
The Mean

Abstract The present work uses Stereoscopic Particle Image Velocimetry (SPIV) to analyze the compressor inlet flow field, with specific emphasis on its turbulence characteristics during flow reversal in order to gain further insight into the inlet flow structures. SPIV experiments were carried out at the inlet of a centrifugal compressor without any recirculation channel at four different rotational speeds (from 80 to 140 krpm) and over the entire mass flow range (from choke to surge) at each speed. Detailed analyses have been carried out for the mean velocity field, the mean vorticity field, and the turbulent statistics including turbulent kinetic energy, Reynolds stress, and the one-dimensional energy spectra. The turbulent kinetic energy at the compressor inlet was observed to increase rapidly along a speed line with decreasing mass flow rate once flow separation started, and the turbulence became more anisotropic. As the flow rate was reduced (along a speed line), the zone with maximum turbulent kinetic energy moved from the periphery toward the center of the inlet duct and also occurred further upstream from the impeller. The Reynolds stress distributions suggest that the Boussinesq assumption of an isotropic eddy viscosity may not be appropriate after the detection of flow reversal. The Reynolds shear stresses were observed to change signs with their corresponding velocity gradients at the tested mass flow rates at different rotational speeds. At the investigated flow rates, the radial gradients in the axial and tangential velocities were found to be most dominant.

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