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.

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.

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.

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.

Experimental Study of the Characteristics of Gas Impinging Streams Using PIV Technique

2013 ◽  
Author(s):  
Wei Wei ◽  
ZhiYi Li ◽  
Fengxia Liu ◽  
Zhijun Liu
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Velocity Fields ◽  
Experimental Equipment ◽  
Piv Technique ◽  
Tracer Particles ◽  
Image Velocimetry

Impinging streams technology has been widely used in many applications in recent years because of its enhancement to the heat and mass transfer between phases. In this paper, in order to investigate the influences of the impinging distance and flow rate on the characters of the flow field, gas-gas impinging streams flow fields are tested experimentally and analyze qualitatively with particle image velocimetry (PIV). The experimental equipment consists of two opposite nozzles which are the same axis. A PIV system is used to measure the characters of the 2-D flow field between two opposite nozzles. The gas is delivered by a compressor through two opposite jets which could be seeded with oil droplets as tracer particles. The effects of the flow rate and impinging distance on the velocity fields of impinging zone are investigated in detail. As the flow rate increases from 0.2 m3/h to 0.8 m3/h, the width of impinging zone increases from 0.25 to 0.5. However, the range of impinging zone does not change significantly as the impinging distance increases from 61mm to 94mm. The results indicate that the PIV technique is an effective method to measure and analyze the characters of impinging streams.

Experiments on Bounded Vortex Flows and Related Particle Transport

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Y. Huang ◽  
J. S. Marshall
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Separation Distance ◽  
Flow Rate Ratio ◽  
Annular Slot ◽  
Image Velocimetry ◽  
Separatrix Curve ◽  
Outlet Flow ◽  
Plate Separation

The flow field generated by the combination of a downward-oriented annular slot jet with a circumferential velocity component and a suction port in the space between two horizontal planes is referred to as a bounded vortex flow. The current paper reports on an experimental study of the flow field and its ability to transport particles. Particle image velocimetry measurement shows that the ratio of the inlet to outlet flow rate and the ratio of the plate separation distance to the jet inlet radius control the wall-normal vortex strength and entrainment of the jet into the suction port. A toroidal vortex ring was also observed to form in certain cases. In particle experiments a separatrix curve is observed beyond which particles roll outward and within which particles roll inward; thus forming a cleaned region with radius that decreases with increase in the flow rate ratio.

scholarly journals Experimental study on fiber suspensions in a curved expansion duct with particle image velocimetry

2012 ◽  
Vol 16 (5) ◽  
pp. 1414-1418 ◽  
Author(s):  
Xiao-Yu Liang ◽  
Huan-Huan Wu ◽  
Cheng-Xu Tu ◽  
Kai Zhang
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Direction ◽  
Internal Flow ◽  
Concave Wall ◽  
Image Velocimetry ◽  
Inlet Flow Rate ◽  
Convex Wall

The visualization measurement of internal flow field in a curved expansion duct is experimentally studied using particle image velocimetry technology and the influence of flow rate on flow field is analyzed. The streamline distribution and related performance curve in the internal flow field can be figured out through further analysis of experiment data. The results show that fiber orientation is mainly affected by velocity gradient, the fibers near the wall are aligned with the flow direction more quickly than the fibers in intermediate region, and the fibers near the concave wall are more quickly aligned with the flow direction than the convex wall. The larger inlet flow rate which will accordingly lead to increase inlet velocity enables the more quick adaptation and steady of fibers in flow direction.

The Impact of the Multiple Reference Frame Interface on Modelling the Interaction Between IGVs and the Impeller in Turbocharger Compressors

2017 ◽  
Author(s):  
Xiangjun Li ◽  
Stephen Spence
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Reference Frame ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Axial Position ◽  
High Rotational Speed ◽  
The Impact ◽  
Multiple Reference

In this paper numerical investigations are presented of how the axial position of the multiple reference frame (MRF) stator-rotor interface between the inlet guide vanes (IGVs) and the impeller would influence the predicted flow field for a turbocharger centrifugal compressor when simulated by the steady RANS method. In the first step, a total of three different axial positions of the MRF IGV-impeller interface were considered and compared with the results of an unsteady simulation to evaluate their accuracy. The results showed that the choice of the MRF interface location significantly influenced the predicted overall performance. At the lower rotational speed, the peak efficiency varied by 1.3% and the corresponding total pressure ratio varied by 0.022. At the high rotational speed, the different axial locations of the MRF interface varied the predicted choke point by 0.012 normalized mass flow rate. The mass flow rate of the near surge (NS) point was over estimated at both the high and low rotational speed by at least 0.038 normalized mass flow rate. Consideration of the flow field suggested that the MRF interface between the IGV and the impeller should be placed towards the upstream side of the available region to avoid being unphysically influenced by its interaction with the non-uniform pressure in the downstream subsonic flow field and to enable a more accurate prediction of the extent of the inducer shock in transonic operating situations. Based on this understanding, a further improvement was made for the setting of the MRF interface by employing a polyline interface. This achieved a more accurate numerical result for the NS operating point at low rotational speeds. The position of the MRF interface for modelling IGVs in a turbocharger compressor should be suitably chosen according to the objectives of the numerical study.

Endoscopic 2D particle image velocimetry (PIV) flow field measurements in IC engines

2002 ◽  
Vol 33 (6) ◽  
pp. 794-800 ◽  
Author(s):  
U. Dierksheide ◽  
P. Meyer ◽  
T. Hovestadt ◽  
W. Hentschel
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Particle Image ◽  
Field Measurements ◽  
Image Velocimetry ◽  
Ic Engines

scholarly journals Manifold reduction techniques for the comparison of crank angle-resolved particle image velocimetry (PIV) data and Reynolds-averaged Navier-Stokes (RANS) simulations in a spark ignition direct injection (SIDI) engine

2021 ◽  
pp. 146808742110131
Author(s):  
Xiaohang Fang ◽  
Li Shen ◽  
Christopher Willman ◽  
Rachel Magnanon ◽  
Giuseppe Virelli ◽  
...  
Keyword(s):  
Flow Field ◽  
Particle Image ◽  
Direct Injection ◽  
Linear Manifold ◽  
Main Flow ◽  
Navier Stokes ◽  
Reduction Techniques ◽  
Image Velocimetry ◽  
Manifold Reduction ◽  
Relevance Index

In this article, different manifold reduction techniques are implemented for the post-processing of Particle Image Velocimetry (PIV) images from a Spark Ignition Direct Injection (SIDI) engine. The methods are proposed to help make a more objective comparison between Reynolds-averaged Navier-Stokes (RANS) simulations and PIV experiments when Cycle-to-Cycle Variations (CCV) are present in the flow field. The two different methods used here are based on Singular Value Decomposition (SVD) principles where Proper Orthogonal Decomposition (POD) and Kernel Principal Component Analysis (KPCA) are used for representing linear and non-linear manifold reduction techniques. To the authors’ best knowledge, this is the first time a non-linear manifold reduction technique, such as KPCA, has ever been used in the study of in-cylinder flow fields. Both qualitative and quantitative studies are given to show the capability of each method in validating the simulation and incorporating CCV for each engine cycle. Traditional Relevance Index (RI) and two other previously developed novel indexes: the Weighted Relevance Index (WRI) and the Weighted Magnitude Index (WMI), are used for the quantitative study. The results indicate that both POD and KPCA show improvements in capturing the main flow field features compared to ensemble-averaged PIV experimental data and single cycle experimental flow fields while capturing CCV. Both methods present similar quantitative accuracy when using the three indexes. However, challenges were highlighted in the POD method for the selection of the number of POD modes needed for a representative reconstruction. When the flow field region presents a Gaussian distribution, the KPCA method is seen to provide a more objective numerical process as the reconstructed flow field will see convergence with an increasing number of modes due to its usage of Gaussian properties. No additional criterion is needed to determine how to reconstruct the main flow field feature. Using KPCA can, therefore, reduce the amount of analysis needed in the process of extracting the main flow field while incorporating CCV.

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