Numerical Investigation of the Unsteady Flow Inside a Centrifugal Compressor Stage With Pipe Diffuser

2013 ◽  
Author(s):  
Daniel R. Grates ◽  
Peter Jeschke ◽  
Reinhard Niehuis
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Measurement Techniques ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor ◽  
The Subject

The subject of this paper is the investigation of unsteady flow inside a transonic centrifugal compressor stage with pipe-diffuser by utilizing unsteady 3D Navier-Stokes simulations (unsteady 3D URANS). The CFD results obtained are compared with detailed experimental data gathered using various steady and unsteady measurement techniques. The basic phenomena and mechanisms of the complex and highly unsteady flow inside the compressor with pipe-diffuser are presented and analyzed in detail.

Numerical Investigation of the Unsteady Flow Inside a Centrifugal Compressor Stage With Pipe Diffuser

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Daniel R. Grates ◽  
Peter Jeschke ◽  
Reinhard Niehuis
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Measurement Techniques ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor ◽  
Computational Fluid Dynamics Cfd ◽  
The Subject

The subject of this paper is the investigation of unsteady flow inside a transonic centrifugal compressor stage with a pipe-diffuser by utilizing unsteady 3D Reynolds-averaged Navier–Stokes simulations (unsteady 3D URANS). The computational fluid dynamics (CFD) results obtained are compared with detailed experimental data gathered using various steady and unsteady measurement techniques. The basic phenomena and mechanisms of the complex and highly unsteady flow inside the compressor with a pipe-diffuser are presented and analyzed in detail.

scholarly journals Comparative Study on Steady and Unsteady Flow in a Centrifugal Compressor Stage

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Changhee Kim ◽  
Changmin Son
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Industrial Development ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Common Procedure ◽  
Vaned Diffuser ◽  
Centrifugal Compressor Stage ◽  
Rans Simulation ◽  
And Performance

Steady Reynolds-averaged Navier-Stokes (RANS) simulation with the mixing-plane approach is the most common procedure to obtain the performance of a centrifugal compressor in an industrial development process. However, the accurate prediction of complicated flow fields in centrifugal compressors is the most significant challenge. Some phenomena such as the impeller-diffuser flow interaction generates the unsteadiness which can affect the steady assumption. The goal of this study is to investigate the differences between the RANS and URANS simulation results in a centrifugal compressor stage. Simulations are performed at three operating points: near surge (NS), design point (DP), and near choke (NC). The results show that the RANS simulation can predict the overall performance with reasonable accuracy. However, the differences between the RANS and URANS simulation are quite significant especially in the region that the flows are highly unsteady or nearly separated. The RANS simulation is still not very accurate to predict the time-dependent quantities of the flow structure. It shows that the URANS calculations are necessary to predict the detailed flow structures and performance. The phenomena and mechanisms of the complex and highly unsteady flow in the centrifugal compressor with a vaned diffuser are presented and analyzed in detail.

1D and 3D-Design Strategies for Pressure Slope Optimization of High-Flow Transonic Centrifugal Compressor Impellers

2018 ◽  
Author(s):  
A. Hildebrandt ◽  
T. Ceyrowsky
Keyword(s):  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Angle Distribution ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Design Point ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor

The present paper deals with the numerical and theoretical investigations of the effect of geometrical dimensions and 1D-design parameters on the impeller pressure slope of a transonic centrifugal compressor stage for industrial process application. A database being generated during the multi-objective and multi-point design process of a high flow coefficient impeller, comprising 545 CFD (Computational Fluid Dynamics) designs is investigated in off-design and design conditions by means of RANS (Reynolds Averaged Navier Stokes) simulation of an impeller with vaneless diffuser. For high flow coefficients of 0.16 < phi < 0.18, the CFD-setup has been validated against measurement data regarding stage and impeller performance taken from MAN test rig experimental data for a centrifugal compressor stage of similar flow coefficient. The paper aims at answering the question how classical design parameter, such as the impeller blade angle distribution, impeller suction diameter and camber line length affect the local and total relative diffusion and pressure slope towards impeller stall operation. A second order analysis of the CFD database is performed by cross-correlating the CFD data with results from impeller two-zone 1D modelling and a rapid loading calculation process by Stanitz and Prian. The statistical covariance of first order 1D-analysis parameters such as the mixing loss of the impeller secondary flow, the slip factor, impeller flow incidence is analyzed, thereby showing strong correlation with the design and off-design point efficiency and pressure slope. Finally, guide lines are derived in order to achieve either optimized design point efficiency or maximum negative pressure slope characteristics towards impeller stall operation.

Experimental and Numerical Investigation of Tip Clearance and Bleed Effects in a Centrifugal Compressor Stage With Pipe Diffuser

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Robert Kunte ◽  
Philipp Schwarz ◽  
Benjamin Wilkosz ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Tip Clearance ◽  
Compressor Stage ◽  
Local Flow ◽  
Centrifugal Compressor Stage ◽  
Centrifugal Stage ◽  
Flow Phenomena ◽  
Fundamental Insight ◽  
The Impact

The subject of this paper is the experimental and numerical investigation of a state-of-the-art high pressure centrifugal compressor stage with pipe diffuser for a jet engine application. This study shows the impact of impeller tip clearance- and bleed-variation on the centrifugal stage. The purpose of this paper is threefold. In the first place, it investigates the effects on the stage performance. Secondly, it seeks to explain local flow-phenomena, especially in the diffuser. Finally, it shows that steady CFD simulations are capable of predicting these phenomena. Experimental data were gathered using conventional pitot and three-hole-probes as well as particle-image-velocimetry. Numerical simulations with the CFD solver TRACE were conducted to get fundamental insight into the flow. Thus, this study contributes greatly towards understanding the principle of the flow phenomena in the pipe diffuser of a centrifugal compressor.

Surge Inception in a Transonic Centrifugal Compressor Stage

2011 ◽  
Author(s):  
Isabelle Tre´binjac ◽  
Nicolas Bulot ◽  
Xavier Ottavy ◽  
Nicolas Buffaz
Keyword(s):  
Centrifugal Compressor ◽  
Short Wavelength ◽  
Stokes Equations ◽  
Pressure Sensors ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Vaned Diffuser ◽  
Choked Flow ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor

Numerical and experimental investigations were conducted in a transonic centrifugal compressor stage composed of a backswept splittered unshrouded impeller and a vaned diffuser. Unsteady 3D simulations were performed with the code elsA that solves the turbulent averaged Navier-Stokes equations, at three operating points: choked flow, peak efficiency and near surge. Unsteady pressure measurements up to 150 kHz were carried out in the entry zone of the vaned diffuser (in the vaneless space and in the semi-vaneless space) when the compressor came into surge. These static pressure sensors were mounted on the shroud enwall. The paper focuses on the vaneless and semi-vaneless space where the surge originates. A detailed analysis of the flow pattern coming from the unsteady computations from choked flow towards surge led to identify the physical mechanisms involved in the surge inception. It is shown that, when approaching surge, the flow is destabilized by a severe modification of the shock system in the vaned diffuser inlet. The first perturbation is acquired from the transducer located just upstream of the shock foot (i.e. on the vane suction side surface), indicating a movement of the shock towards the vaneless space. This perturbation travels upstream and leads to the strongest short-wavelength perturbation acquired from the transducer located just upstream of the vane leading edge. This strongest short-wavelength perturbation which level may reach almost four times the mean exit pressure value triggers the full scale instability.

Numerical investigation & comparison of a tandem-bladed turbocharger centrifugal compressor stage with conventional design

2014 ◽  
Vol 23 (6) ◽  
pp. 523-534
Author(s):  
Syed Noman Danish ◽  
Shafiq Rehman Qureshi ◽  
Abdelrahman EL-Leathy ◽  
Salah Ud-Din Khan ◽  
Usama Umer ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Conventional Design

One-Dimensional and Three-Dimensional Design Strategies for Pressure Slope Optimization of High-Flow Transonic Centrifugal Compressor Impellers

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
A. Hildebrandt ◽  
T. Ceyrowsky
Keyword(s):  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Angle Distribution ◽  
Compressor Stage ◽  
Design Point ◽  
One Dimensional ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor

This paper deals with the numerical and theoretical investigations of the effect of geometrical dimensions and one-dimensional (1D)-design parameters on the impeller pressure slope of a transonic centrifugal compressor stage for industrial process application. A database being generated during the multi-objective and multipoint design process of a high flow coefficient impeller, comprising 545 computational fluid dynamics (CFD) designs is investigated in off-design and design conditions by means of Reynolds-averaged Navier–Stokes (RANS) simulation of an impeller with vaneless diffuser. For high flow coefficients of 0.16 < ϕdes < 0.18, the CFD-setup has been validated against measurement data regarding stage and impeller performance taken from MAN test rig experimental data for a centrifugal compressor stage of similar flow coefficient. This paper aims at answering the question how classical design parameter, such as the impeller blade angle distribution, impeller suction diameter, and camber line length affect the local and total relative diffusion and pressure slope toward impeller stall operation. A second-order analysis of the CFD database is performed by cross-correlating the CFD data with results from impeller two-zone 1D modeling and a rapid loading calculation process by Stanitz and Prian. The statistical covariance of first-order 1D-analysis parameters such as the mixing loss of the impeller secondary flow, the slip factor, impeller flow incidence is analyzed, thereby showing strong correlation with the design and off-design point efficiency and pressure slope. Finally, guide lines are derived in order to achieve either optimized design point efficiency or maximum negative pressure slope characteristics toward impeller stall operation.

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