Dynamic Features and their Propagation in a Centrifugal Compressor Housing with Ported Shroud

2012 ◽  
Author(s):  
Matthieu Gancedo ◽  
Erwann Guillou ◽  
Ephraim Gutmark ◽  
Ashraf Mohamed
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Features ◽  
Ported Shroud

Impact of Impeller Casing Treatment on the Acoustics of a Small High Speed Centrifugal Compressor

2018 ◽  
Author(s):  
Sidharath Sharma ◽  
Jorge García-Tíscar ◽  
John M. Allport ◽  
Martyn L. Jupp ◽  
Ambrose K. Nickson
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Operating Conditions ◽  
Aerodynamic Noise ◽  
Noise Sources ◽  
Casing Treatment ◽  
Active Research ◽  
Ported Shroud ◽  
The Impact

Ported shroud casing treatment is widely used to delay the onset of surge and thereby enhancing the aerodynamic stability of a centrifugal compressor by recirculating the low momentum fluid in the blade passage. Performance losses associated with the use of recirculation casing treatment are well established in the literature and this is an area of active research. The other, less researched aspect of the casing treatment is its impact on the acoustics of the compressor. This work investigates the impact of ported shroud casing treatment on the acoustic characteristics of the compressor. The flow in two compressor configurations viz. with and without casing treatment operating at the design operating conditions of an iso-speed line are numerically modelled and validated with experimental data from gas stand measurements. The pressure fluctuations calculated as the flow solution are used to compute the spectral signatures at multiple locations to investigate the acoustic phenomenon associated with each configuration. Propagation of the frequency content through the ducts has been estimated with the aid of method of characteristics to enhance the content coming from the compressor. Expected tonal aerodynamic noise sources such as monopole (buzz-saw tones) and dipole (Blade Pass Frequency) are clearly identified in the acoustic spectra of the two configurations. The comparison of two configurations shows higher overall levels and tonal content in the case of a compressor with ported shroud operating at design conditions due to the presence of ‘mid-tones’.

scholarly journals Numerical Flow Analysis of a Centrifugal Compressor with Ported and without Ported Shroud

2014 ◽  
Author(s):  
Bernhard Semlitsch ◽  
JyothishKumar V ◽  
Mihai Mihaescu ◽  
Laszlo Fuchs ◽  
Ephraim Gutmark ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Flow Analysis ◽  
Ported Shroud ◽  
Numerical Flow Analysis

Parametric Study on Ported Shroud Locations and Geometries for a Turbocharger Compressor

2019 ◽  
Author(s):  
Suheab Thamizullah ◽  
Abdul Nassar ◽  
Antonio Davis ◽  
Gaurav Giri ◽  
Leonid Moroz
Keyword(s):  
Centrifugal Compressor ◽  
Combustion Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Entire Study ◽  
Operating Condition ◽  
Baseline Design ◽  
Operating Range ◽  
Ported Shroud ◽  
The Impact

Abstract Turbochargers are commonly used in automotive engines to increase the internal combustion engine performance during off-design operating conditions. When used, the widest operating range for the turbocharger is desired, which is limited on the compressor side by the choke condition and the surge phenomenon. The ported shroud technology is used to extend the operable working range of the compressor, by permitting flow disturbances that block the blade passage to escape and stream back through the shroud cavity to the compressor inlet. The impact of this technology, on a speed-line, at near optimal operating condition, near choke operating condition and near surge operating condition is investigated. The ported shroud (PS) self-recirculating casing treatment is widely used to delay the onset of surge by enhancing the aerodynamic stability of the turbocharger compressor. While the ported shroud design delays surge, it usually comes with a small penalty in efficiency. This research involves designing a single-stage centrifugal compressor for the given specifications, considering the application of an automotive turbocharger. The ported shroud was then introduced in the centrifugal compressor. The performance characteristics were obtained, both at the design and at off-design conditions, both with and without the ported shroud. The performance was compared at various off-design operating speed lines. The entire study, from designing the compressor to optimizing the ported shroud configuration, was performed using the commercial AxSTREAM® software platform. Parametric studies were performed to study the effect of ported shroud axial location along the blade axial length on the operating range and performance. The baseline design, without the ported shroud (P0), and the final geometry with it for all PS inlet axial locations (P1 to P5) were analysed using a commercial CFD package and the results were compared with those from the streamline solver.

Characterizing Flow Effects of Ported Shroud Casing Treatment on Centrifugal Compressor Performance

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
George A. Christou ◽  
Choon S. Tan ◽  
Borislav T. Sirakov ◽  
Vai-Man Lei ◽  
Giuseppe Alescio
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Flow Path ◽  
Main Flow ◽  
Tip Leakage Flow ◽  
Casing Treatment ◽  
Compressor Performance ◽  
Flow Effects ◽  
Ported Shroud

This paper presents an investigation of the effects of ported shroud (PS) self-recirculating casing treatment used in turbocharger centrifugal compressors for increasing the operable range. The investigation consists of computing three-dimensional flow in a representative centrifugal compressor with and without PS at various levels of approximations in flow physics and geometrical configuration; this provides an enabler for establishing the causal link between PS flow effects and compressor performance changes. It is shown that the main flow path perceives the PS flow as a combination of flow actuations that include injection and removal of mass flow and injection of axial momentum and tangential momentum. A computational model in which the presence of the PS is replaced by imposed boundary conditions (BCs) that reflect the individual flow actuations has thus been formulated and implemented. The removal of a fraction of the inducer mass flow has been determined to be the dominant flow actuation in setting the performance of PS compressors. Mass flow removal reduces the flow blockage associated with the impeller tip leakage flow and increases the diffusion in the main flow path. Adding swirl to the injected flow in the direction opposite to the wheel rotation results in an increase of the stagnation pressure ratio and a decrease of the efficiency. The loss generation in the flow path has been defined to rationalize efficiency changes associated with PS compressor operation.

scholarly journals Empirical Design Considerations for Industrial Centrifugal Compressors

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Cheng Xu ◽  
Ryoichi S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
Centrifugal Compressors ◽  
Design Guideline ◽  
Stage Design ◽  
Centrifugal Stage ◽  
Complex Design ◽  
Compressor Design ◽  
Computational Fluid Dynamics Cfd ◽  
Ported Shroud ◽  
Empirical Design

Computational Fluid Dynamics (CFD) has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

Numerical Designed Experiment to Optimize a Ported Shroud to Extend the Operability Margin of a Centrifugal Compressor

2005 ◽  
Author(s):  
J. Slovisky ◽  
M. L. Mansour ◽  
M. T. Barton ◽  
D. L. Palmer
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Numerical Technique ◽  
Fluid Dynamic ◽  
Constant Width ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Stall Margin ◽  
Designed Experiment ◽  
Ported Shroud

This paper describes the Computational Fluid Dynamic (CFD) numerical optimization of a modern centrifugal compressor impeller with a ported shroud for increased surge margin. The vent configuration selected was a full circumference, constant-width slot. A multiblock, steady flow three dimensional (3D) viscous RANS model (ADPAC) is used with parallel processing capability to increase computational speed. Grid generation is performed in an automated fashion to enable the timely optimization of the ported shroud configuration. A designed experiment (DoE) approach is used to minimize the number of vent configurations to be modeled, to ensure that factor interaction effects are captured, and to facilitate the definition of an optimum vent configuration. The DoE is a 2 factor, 2 level full factorial experiment with a center point included to detect possible curvature in the solution surface. The factors optimized are slot width and the flow-wise location of the slot. The numerical technique verifies the ability of the ported shroud to extend compressor stall margin at the part-speed operating condition, while maintaining acceptable high speed performance, in good agreement with test data for a similar impeller with a ported shroud. The use of a DoE method coupled with CFD modeling identified an optimized vent configuration with a minimum of time and effort. The CFD results also provide enhanced understanding of the device physics.

Casing Treatment of Centrifugal Compressors

2015 ◽  
Author(s):  
Jisha Noushad ◽  
Anand Babu Dhamarla ◽  
Pavan Kumar
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
Reverse Flow ◽  
Pressure Fluctuations ◽  
Centrifugal Compressors ◽  
Flow Rates ◽  
Casing Treatment ◽  
Operating Range ◽  
Mass Flow Rates ◽  
Ported Shroud

The operating range of any compressor is controlled by Surge and Choke. Surge occurs at lower mass flow rates with large pressure fluctuations and flow reversals, while choke occurs at higher mass flow rates when the flow rate reaches the limit which compressor can discharge. Ported shroud is a cost effective casing treatment that can greatly improve operating range of centrifugal compressors. By removing the stagnant and reverse flow from shroud wall boundary-layer region and recirculating it to impeller inlet, it has been demonstrated that larger range of operability can be achieved without much loss on compressor efficiency. This paper demonstrates the improvement of a centrifugal compressor operational range with ported shroud configuration. A series of CFD simulations were carried out with open source centrifugal compressor geometry (NASA HPCC 4:1) to create performance characteristics/speed-lines. The CFD methodology and practices were validated by comparing the results with the experimental data. Performance evaluation of ported shroud configuration is done with respect to solid shroud. Ported shroud compressor is proven to give higher choke mass flow and also a better surge margin compared to the Solid shroud model. The phenomena of in-flowing and out-flowing port have also been demonstrated. Emphasis was given to understand how ported shroud helps to achieve a better performance. A design optimization study has also been carried out in order to establish the optimum ported shroud configuration. Design parameter such as port location has been selected and the effect of this parameter on the performance of the compressor is studied using CFD. Optimum port geometry was proposed.

Aerodynamics of a Centrifugal Compressor With a Double Sided Impeller

2011 ◽  
Author(s):  
Vai-Man Lei
Keyword(s):  
Centrifugal Compressor ◽  
Stability Limit ◽  
Low Flow ◽  
Recirculation Flow ◽  
Flow Capacity ◽  
Operation Modes ◽  
Compressor Inlet ◽  
Parallel Mode ◽  
The Stability ◽  
Ported Shroud

A double sided impeller, which consists of two impellers arranged in a back-to-back configuration with the backdisks eliminated, enables a single centrifugal compressor to have flow capacity similar to two compressors working in parallel but with a smaller packaging size. It reduces inertia of the rotating group and helps improve transient response. The smaller impeller diameter also enhances turbine performance by improving the compressor-turbine matching. These attributes are very attractive for automotive turbocharging applications. As a consequence of a common compressor inlet and diffuser, the two compressor sides interact and two operation modes exist. In the parallel mode, the two compressor sides work under comparable condition and the overall compressor behaves similar to a conventional compressor. As flow rate is reduced below a transition value, the system operates in a single-compressor mode with one compressor side flowing significantly more. The compressor side that flows more operates away from the stability limit and the side with low flow remains stable because of heavy recirculation flow with a ported shroud. Characteristics of the two operation modes are elucidated with test and CFD data.

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