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.

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

2011 ◽  
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.

Experimental Investigation of a Truncated Pipe Diffuser With a Tandem Deswirler in a Centrifugal Compressor Stage

2012 ◽  
Author(s):  
Robert Kunte ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Rise ◽  
Compressor Stage ◽  
Local Flow ◽  
Centrifugal Compressor Stage ◽  
Geometric Configurations ◽  
Flow Phenomena ◽  
Fundamental Insight ◽  
The Impact

The subject of this paper is the experimental investigation of three different geometric configurations of the diffusing system in a high pressure centrifugal compressor stage for a jet engine application. The objective of this study is twofold. On the one hand, it seeks to explain the impact of truncating a diffuser and a redesigned tandem deswirler on the global stage performance; on the other hand, it aims to correlate the performance differences with local flow phenomena. For this purpose, a state-of-the-art centrifugal compressor test rig was used. Particle image velocimetry measurements visualize the separation behavior in the pipe diffuser passage. Thereby it is shown that the truncation of the diffuser changed the boundary conditions for the downstream deswirler including a high incidence. Thus, a new tandem deswirler design was implemented and measured. Moreover, the relative position of the two tandem rows is investigated. An optimal relative circumferential position for the stage efficiency and static pressure rise was found. This paper gives fundamental insight into the physical mechanisms of the influence of three geometric configurations in a centrifugal compressor stage, especially in the pipe diffuser and the deswirler. Hence, this study contributes in furthering knowledge of the fundamental principles of flow phenomena in the diffusing system of a centrifugal compressor.

Experimental Investigation of a Truncated Pipe Diffuser With a Tandem Deswirler in a Centrifugal Compressor Stage

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Robert Kunte ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Rise ◽  
Compressor Stage ◽  
Local Flow ◽  
Centrifugal Compressor Stage ◽  
Geometric Configurations ◽  
Flow Phenomena ◽  
Fundamental Insight ◽  
The Impact

The subject of this paper is the experimental investigation of three different geometric configurations of the diffusing system in a high pressure centrifugal compressor stage for a jet engine application. The objective of this study is twofold. On the one hand, it seeks to explain the impact of truncating a diffuser and a redesigned tandem deswirler on the global stage performance; on the other hand, it aims to correlate the performance differences with local flow phenomena. For this purpose, a state-of-the-art centrifugal compressor test rig was used. Particle image velocimetry measurements visualize the separation behavior in the pipe diffuser passage. Thereby it is shown that the truncation of the diffuser changed the boundary conditions for the downstream deswirler including a high incidence. Thus, a new tandem deswirler design was implemented and measured. Moreover, the relative position of the two tandem rows is investigated. An optimal relative circumferential position for the stage efficiency and static pressure rise was found. This paper gives fundamental insight into the physical mechanisms of the influence of three geometric configurations in a centrifugal compressor stage, especially in the pipe diffuser and the deswirler. Hence, this study contributes in furthering knowledge of the fundamental principles of flow phenomena in the diffusing system of a centrifugal compressor.

Numerical Investigation of the Effect of Diffuser and Volute Design Parameters on the Performance of a Centrifugal Compressor Stage

2016 ◽  
Author(s):  
Lei Yu ◽  
William T. Cousins ◽  
Feng Shen ◽  
Georgi Kalitzin ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Gas Flow ◽  
Pressure Rise ◽  
Design Parameters ◽  
Compressor Stage ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Centrifugal Stage ◽  
And Performance ◽  
The Impact

In this effort, 3D CFD simulations are carried out for real gas flow in a refrigeration centrifugal compressor. Both commercial and the in-house CFD codes are used for steady and unsteady simulations, respectively. The impact on the compressor performance with various volute designs and diffuser modifications are investigated with steady simulations and the analysis is focused on both the diffuser and the volute loss, in addition to the flow distortion at impeller exit. The influence of the tongue, scroll diffusion ratio, diffuser length, and cross sectional area distribution is examined to determine the impact on size and performance. The comparisons of total pressure loss, static pressure recovery, through flow velocity, and the secondary flow patterns for different volute designs show that the performance of the centrifugal compressor depends upon how well the scroll portion of the volute collects the flow from the impeller and achieves the required pressure rise with minimum flow losses in the overall diffusion process. Finally, the best design is selected based on compressor stage pressure rise and peak efficiency improvement. An unsteady simulation of the full wheel compressor stage was carried out to further examine the interaction of impeller, diffuser and the volute. The unsteady flow interactions are shown to have a major impact on the performance of the centrifugal stage.

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

Impact of Manufacturing Variability on the Aerodynamic Performance of a Centrifugal Compressor Stage With Curvilinear Blades

2016 ◽  
Author(s):  
A. Panizza ◽  
R. Valente ◽  
D. Rubino ◽  
L. Tapinassi
Keyword(s):  
Centrifugal Compressor ◽  
Sampling Methods ◽  
Aerodynamic Performance ◽  
High Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Compressor Stage ◽  
Centrifugal Compressor Stage ◽  
Performance Variability ◽  
The Impact

The goal of the present study is to quantify the uncertainty in the aerodynamic performance of a centrifugal compressor stage with curvilinear impeller blades, due to impeller manufacturing variability. Impellers with curvilinear element blades allow a greater control of secondary flows with respect to impellers having ruled blades. High flow coefficient impellers for centrifugal compressors exhibit larger secondary flow than medium or low flow coefficient impellers, due to the stronger curvature of the flow path and the larger blade height for the same external diameter. Thus curvilinear blade impellers allow to improve the efficiency and range of high flow coefficient centrifugal compressor stages. As the design of these impellers is more complex than the design of ruled blade impellers, it is important to estimate the impact of the impeller manufacturing variability on the performance of the full stage. Sampling methods are often used in uncertainty propagation studies. However, sampling based approaches require a very large number of samples to have an accurate estimate of the performance uncertainty. 3D steady RANS computations are necessary to capture the impact of the geometric variability of the curvilinear blade impeller, on the stage performance. Thus, sampling methods would require an excessive computational time. In this work, the Polynomial Chaos Expansion (PCE) method with arbitrary probability distributions, implemented in DAKOTA, is used to reduce the number of runs required for the uncertainty quantification study. Manufacturing measurement data are been used to derive the histograms of the main impeller design parameters. From these histograms, numerically-generated orthogonal polynomials are computed for each parameter using a discretized Stieltjes procedure. Stochastic expansion methods such as PCE suffer from the curse of dimensionality, i.e., an exponential increase in the number of runs as the number of uncertain parameters increases. To mitigate the curse of dimensionality, sparse grids are used, which allow a drastic reduction of the number of runs. The results of the study show that the performance variability is small, thus our design with curvilinear element blades is robust with respect to impeller manufacturing variability. Using Sobol indices, we also rank the design parameters according to their impact on the performance variability.

scholarly journals Experimental Investigation of Unsteady Flow Phenomena in a Centrifugal Compressor Vaned Diffuser of Variable Geometry

1999 ◽  
Vol 121 (4) ◽  
pp. 763-771 ◽  
Author(s):  
F. Justen ◽  
K. U. Ziegler ◽  
H. E. Gallus
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Fluctuations ◽  
Suction Side ◽  
Front Wall ◽  
Compressor Stage ◽  
Vaned Diffuser ◽  
Centrifugal Compressor Stage ◽  
Impeller Outlet ◽  
Flow Phenomena ◽  
Radial Gap

The behavior of vaned radial diffusers is generally considered to be due to the flow phenomena in the vaneless and the semi-vaned space in the diffuser inlet region. Even considering unsteady aspects, the adjacent diffuser channel is regarded as less important. The flat wedge vaned diffuser of the centrifugal compressor stage investigated allows an independent continuous adjustment of the diffuser vane angle and the radial gap between impeller outlet and diffuser vane inlet, so that information about the importance of these geometric parameters can be obtained. The time-dependent pressure distribution on the diffuser front wall and on the suction and pressure surfaces of the diffuser vanes reveal that in the semi-vaned space mainly the region near the vane suction side is influenced by the unsteady impeller-diffuser interaction. Downstream in the diffuser channel the unsteadiness does not decay. Here, pressure fluctuations are appearing that are distinctly higher than the pressure fluctuations in the vaneless space. An estimation of the influence of the unsteadiness on the operating performance of the centrifugal compressor stage is made by measurements at choke and surge limit for different diffuser geometries.

Numerical Investigation of Different Casing Treatments on Performance of a High Speed Centrifugal Compressor Stage

2011 ◽  
Author(s):  
Yan Ma ◽  
Guang Xi ◽  
Guangkuan Wu
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
High Speed ◽  
The Other ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Centrifugal Compressor Stage ◽  
And Performance ◽  
Casing Treatments

In this paper, two different casing treatment devices—one adopting inlet recirculation at the shroud side of the impeller inlet and the other adopting circumferential casing grooves at the shroud side of the vaneless space, are designed for a high speed centrifugal compressor stage. The effects of different casing treatments to the flow range and performance of the centrifugal compressor stage are studied numerically. The results indicate that traditional inlet recirculation at impeller inlet does not extend the stall margin of the stage and the performance deteriorates due to the adding of the extra device. The study also shows that, when the location of the bleed slot moves downstream, the performance of the stage deteriorates due to the longer flow path. Moreover, the 2mm depth circumferential casing grooves extend the stall margin by about 12.05%. By contrast, the 6mm depth and 10mm depth grooves extend the stall margin by 3% and 2.4% respectively.

Experimental and Numerical Investigation of the Flow in a Vaneless Diffuser of a Centrifugal Compressor Stage. Part 2: Numerical Investigation

2005 ◽  
Vol 219 (10) ◽  
pp. 1061-1068 ◽  
Author(s):  
T Sato ◽  
J M Oh ◽  
A Engeda
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Centrifugal Compressor Stage ◽  
Improved Performance ◽  
Very High

As user demands grew for improved performance and more reliable equipment and as compressor vendors sought improved analytical and design methodologies, the application of computational fluid dynamics (CFD) in the industrial world became a necessity. Fortunately, large increases in available, economic computing power together with development of improved computational methods now provide the industrial designer with much improved analytic capability. As CFD algorithms and software have continued to be developed and refined, it remains essential that validation studies be conducted in order to ensure that the results are both sufficiently accurate and can be obtained in a robust and predictable manner. Part I of this paper presented detailed flow measurements in a vaneless diffuser of a centrifugal compressor stage with a very high flow coefficient radial impeller, where measurements were carried out in the vaneless diffuser at seven radial positions downstream of the radial impeller designed for a very high flow coefficient of ϕ = 0.2. This paper, Part II, attempts to verify and validate the results numerically.

Experimental and Numerical Investigation of Vaned Hub and Shroud Wall Contoured Diffusers Designed to Improve Flexibility and Efficiency of an Open Impeller Centrifugal Compressor Stage

2021 ◽  
Author(s):  
Daniel Hermann ◽  
Manfred Wirsum ◽  
Douglas Robinson ◽  
Philipp Jenny
Keyword(s):  
Centrifugal Compressor ◽  
State Of The Art ◽  
Pressure Ratio ◽  
Design Stage ◽  
Total Efficiency ◽  
Compressor Stage ◽  
Local Flow ◽  
Efficient Operation ◽  
Centrifugal Compressor Stage ◽  
Operating Range

Abstract State-of-the-art centrifugal compressor stages are required to provide both a flexible and a highly efficient operation. To extend the stable operating range and to improve the design-point polytropic total-to-total efficiency of an open impeller centrifugal compressor stage, three vaned contoured diffusers characterized by geometric modifications of the hub and shroud wall in the vaneless space upstream the diffuser vanes and within the diffuser passages were designed. In this paper, a shroud wall, a hub wall and a hub and shroud wall contoured diffuser and a state-of-the-art baseline diffuser are experimentally examined. For the hub-contoured diffuser an operating range extension of 5.3% was measured at design stage Mach number. For the shroud-contoured diffuser an improvement of polytropic total-to-total efficiency by up to 0.3% is observed. The experimental data including normalized total-to-static pressure ratio and 5-hole-probe data is utilized to validate the numerical setup. By means of the CFD simulations the hub- and the shroud-contoured diffuser designs are analyzed and the hub-contoured diffuser’s effect on the local flow at diffuser vane leading edge is investigated. The results illustrate the local effect of the hub-contoured diffuser design on the flow field in the examined centrifugal compressor stage.

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