The Effect of a Diffuser on the Characteristic of Stable Operation of a Centrifugal Compressor Stage PDF Download
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Author: N. L. Zeldes Publisher: ISBN: Category : Languages : en Pages : 19
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: N. L. Zeldes Publisher: ISBN: Category : Languages : en Pages : 19
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: David W. Erickson (S.M.) Publisher: ISBN: Category : Languages : en Pages : 270
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: David Gordon Wilson Publisher: MIT Press ISBN: 0262325810 Category : Technology & Engineering Languages : en Pages : 625
Book Description
The second edition of a comprehensive textbook that introduces turbomachinery and gas turbines through design methods and examples. This comprehensive textbook is unique in its design-focused approach to turbomachinery and gas turbines. It offers students and practicing engineers methods for configuring these machines to perform with the highest possible efficiency. Examples and problems are based on the actual design of turbomachinery and turbines. After an introductory chapter that outlines the goals of the book and provides definitions of terms and parts, the book offers a brief review of the basic principles of thermodynamics and efficiency definitions. The rest of the book is devoted to the analysis and design of real turbomachinery configurations and gas turbines, based on a consistent application of thermodynamic theory and a more empirical treatment of fluid dynamics that relies on the extensive use of design charts. Topics include turbine power cycles, diffusion and diffusers, the analysis and design of three-dimensional free-stream flow, and combustion systems and combustion calculations. The second edition updates every chapter, adding material on subjects that include flow correlations, energy transfer in turbomachines, and three-dimensional design. A solutions manual is available for instructors. This new MIT Press edition makes a popular text available again, with corrections and some updates, to a wide audience of students, professors, and professionals.
Author: Publisher: ISBN: Category : Aeronautics Languages : en Pages : 790
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: David Gordon Wilson Publisher: ISBN: Category : Technology & Engineering Languages : en Pages : 632
Book Description
One of the only texts to focus on turbomachinery and gas turbines from the 'design' point of view, this volume reviews the necessary thermodynamics, gives extensive design data, provides engine and component illustrations (with comments on good and less-than-good design features), and contains many worked examples - allowing students to produce preliminary designs that can be made and run quickly - as early as Ch. 5. More comprehensive than similar texts, it features a simplified - and more accurate thermodynamic treatment that eliminates the confusing use of 'gamma' and specific heat together, and provides individual full-chapter coverage of axial-flow turbines and compressors and radial-flow versions of the same. *Contains a Brief History of Turbomachinery. *Features a design perspective throughout - and enables students to develop a preliminary design after Ch. 5. *Offers a unified treatment of energy transfer and vector diagrams - focusing on principles that can be applied easily to compressors, pumps, turbines - radial and axial. *Includes specialized chapters that give far more design data than other similar texts - allowing students to produce a design that can be made and r
Author: R. K. Turton Publisher: Springer Science & Business Media ISBN: 9401096899 Category : Science Languages : en Pages : 213
Book Description
This text outlines the fluid and thermodynamic principles that apply to all classes of turbomachines, and the material has been presented in a unified way. The approach has been used with successive groups of final year mechanical engineering students, who have helped with the development of the ideas outlined. As with these students, the reader is assumed to have a basic understanding of fluid mechanics and thermodynamics. However, the early chapters combine the relevant material with some new concepts, and provide basic reading references. Two related objectives have defined the scope of the treatment. The first is to provide a general treatment of the common forms of turbo machine, covering basic fluid dynamics and thermodynamics of flow through passages and over surfaces, with a brief derivation of the fundamental governing equations. The second objective is to apply this material to the various machines in enough detail to allow the major design and performance factors to be appreciated. Both objectives have been met by grouping the machines by flow path rather than by application, thus allowing an appreciation of points of similarity or difference in approach. No attempt has been made to cover detailed points of design or stressing, though the cited references and the body of information from which they have been taken give this sort of information. The first four chapters introduce the fundamental relations, and the suc ceeding chapters deal with applications to the various flow paths.
Author: Theodore Gresh Publisher: Newnes ISBN: 0080529623 Category : Technology & Engineering Languages : en Pages : 215
Book Description
Compressor Performance is a reference book and CD-ROM for compressor design engineers and compressor maintenance engineers, as well as engineering students. The book covers the full spectrum of information needed for an individual to select, operate, test and maintain axial or centrifugal compressors. It includes basic aerodynamic theory to provide the user with the "how's" and "why's" of compressor design. Maintenance engineers will especially appreciate the troubleshooting guidelines offered. Includes many example problems and reference data such as gas properties and flow meter calculations to enable easy analysis of compressor performance in practice. Includes companion CD with computer programs.M. Theodore Gresh has been with the Elliot Company in Jeannette, Pennsylvania, since 1975, initially working on the mechanical and aerodynamic design and application of centrifugal compressors. Unrivalled coverage of the theory and practical use of all kinds of compressors in industrial use from an industry-leading company sourceComplete subject reference and learning resource in one stop, suitable for newly graduated engineers and experienced professional reference useIncludes companion CD-ROM
Author: N. L. Zeldes
Author: N. L. Zeldes
Author: David W. Erickson (S.M.)
Author: David Gordon Wilson
Author: 
Author: Frank Florian Szczesny
Author: David Gordon Wilson
Author: R. K. Turton
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Author: Theodore Gresh
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