Author: Uwe Zachau
Publisher:
ISBN: 9783832268312
Category : Compressors
Languages : en
Pages : 226

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Book Description

Author: Ali Pinarbasi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Presented at the International Gas Turbine and Aeroengine Congress and Exposition, Houston, Texas - June 5-8, 1995.

Author: David W. Erickson (S.M.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 270

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Book Description
This research characterizes the performance of a centrifugal compressor stage with a special focus on the pipe diffuser. Two diffuser configurations are studied, one of which is a truncated version of the other. Experimental data acquired on a research compressor stage is interrogated along with a set of well-designed Reynolds-Averaged Navier Stokes computations, complemented by reduced order flow modeling. The fundamental performance-limiting flow mechanisms in the diffuser are identified and used to physically relate important geometry features and operating conditions to the observed compressor pressure rise, efficiency, and operability characteristics. Despite large differences in their geometry, the two diffuser configurations exhibit similar pressure recovery characteristics due to differences in exit nonuniformity and flow angle which result in similar effective area ratios. Variations in the diffuser pressure recovery coefficient with operating point are found to be most influenced by the diffuser inlet flow angle, and secondly by the inlet Mach number. The diffuser inlet flow angle has the primary effect of setting the diffuser inlet one-dimensional area ratio, increasing diffusion at high flow angles. In addition, the diffuser incidence angle influences the formation of counter-rotating vortex pairs that persist throughout the diffuser passage. Using a two-dimensional integral boundary layer model that is modified to accommodate three-dimensional effects as source terms, these secondary flows are shown to detrimentally impact the diffuser pressure rise capability by accumulating high loss flow along the diffuser wall near the plane of symmetry between the vortices. This contributes to the extent and location of a large diffuser passage separation, especially for the baseline diffuser. The impact of the vortices on the boundary layer growth rate is shown to scale inversely with diffuser aspect ratio. The major performance difference between the two diffuser configurations is that the truncated diffuser configuration experiences enhanced stall margin over the baseline diffuser at the design speed. These differences are traced to reduced secondary flows influence and thus reduced separation extent for the higher aspect ratio truncated diffuser. It is hypothesized that the onset of stall for the baseline diffuser configuration is initiated by the transition of the vortex location and corresponding passage separation between diffuser pressure and suction sides with increasing cusp incidence. Conversely, because the extent of the passage separation in the truncated diffuser is diminished due to the higher aspect ratio, the switch in separation side does not immediately initiate instability. The fact that secondary flows have a large influence on diffuser pressure rise capability and compressor stability is counter to conventional preliminary diffuser design approaches which neglect such 3D effects. The findings of this research may therefore be considered during preliminary design optimization to produce better-performing diffuser designs.

Author: N. L. Zeldes
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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Book Description
Experimental results are presented from studies of stages of centrifugal compressors with different diffusors in relation to geometric characteristics of channels and grids with the number of vanes and vane placement angle are varied. A well defined analytic relationship has been established between the onset of flow separation with the moment of equality of the average flow angle at the outlet from the ring with intake angles of diffusor vane placement. Recording of the moment of onset of separation by oscillography and study of flow formation in the gap behind the ring with a pneumo probe confirmed the conclusion of constancy of flow angle in separation independently of rotor revolutions and affords tracking the analytic and experimental limits of separation for satisfactory agreement.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 112

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Book Description

Author: Michael Casey
Publisher: Cambridge University Press
ISBN: 1108271464
Category : Technology & Engineering
Languages : en
Pages : 790

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Book Description
An introduction to the theory and engineering practice that underpins the component design and analysis of radial flow turbocompressors. Drawing upon an extensive theoretical background and years of practical experience, the authors provide descriptions of applications, concepts, component design, analysis tools, performance maps, flow stability, and structural integrity, with illustrative examples. Features wide coverage of all types of radial compressor over many applications unified by the consistent use of dimensional analysis. Discusses the methods needed to analyse the performance, flow, and mechanical integrity that underpin the design of efficient centrifugal compressors with good flow range and stability. Includes explanation of the design of all radial compressor components, including inlet guide vanes, impellers, diffusers, volutes, return channels, de-swirl vanes and side-streams. Suitable as a reference for advanced students of turbomachinery, and a perfect tool for practising mechanical and aerospace engineers already within the field and those just entering it.

Author: James P. Johnston
Publisher:
ISBN:
Category : Diffusers
Languages : en
Pages : 16

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Book Description

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836

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Book Description

Author: Pennsylvania State College. Ordnance Research Laboratory
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 74

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Book Description

Author: Rene Van den Braembussche
Publisher: John Wiley & Sons
ISBN: 1119424097
Category : Technology & Engineering
Languages : en
Pages : 418

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Book Description
A comprehensive overview of fluid dynamic models and experimental results that can help solve problems in centrifugal compressors and modern techniques for a more efficient aerodynamic design. Design and Analysis of Centrifugal Compressors isacomprehensive overview of the theoretical fluid dynamic models describing the flow in centrifugal compressors and the modern techniques for the design of more efficient centrifugal compressors. The author — a noted expert in the field, with over 40 years of experience — evaluates relevant numerical and analytical prediction models for centrifugal compressors with special attention to their accuracy and limitations. Relevant knowledge from the last century is linked with new insights obtained from modern CFD. Emphasis is to link the flow structure, performance and stability to the geometry of the different compressor components. Design and Analysis of Centrifugal Compressors is an accessible resource that combines theory with experimental data and previous research with recent developments in computational design and optimization. This important resource Covers the basic information concerning fluid dynamics that are specific for centrifugal compressors and clarifies the differences with axial compressors Provides an overview of performance prediction models previously developed in combination with extra results from research conducted by the author Describes helpful numerical and analytical models for the flow in the different components in relation to flow stability, operating range and performance Includes the fundamental information for the aerodynamic design of more efficient centrifugal compressors Explains the use of computational fluid dynamics (CFD) for the design and analysis of centrifugal compressors Written for engineers, researchers and designers in industry as well as for academics specializing in the field, Design and Analysis of Centrifugal Compressors offers an up to date overview of the information needed for the design of more effective centrifugal compressors.