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Book Synopsis Blade Passage Flow Structure Effects on Axial Compressor Rotating Stall Inception by : Donald Andrew Hoying
Download or read book Blade Passage Flow Structure Effects on Axial Compressor Rotating Stall Inception written by Donald Andrew Hoying and published by . This book was released on 1996 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Role of blade passage flow structures in axial compressor rotating stall inception, ASME 98-GT-588 by : Donald A. Hoying
Download or read book Role of blade passage flow structures in axial compressor rotating stall inception, ASME 98-GT-588 written by Donald A. Hoying and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Stockholm, Sweden, Jun 2-Jun 5, 1998.
Book Synopsis Observed Flow Characteristics of Rotating Stall Inception and Its Prevention Using Discrete Tip Injection in the NASA Stage 35 Axial Compressor with New Analysis Methods by : Benjamin P. Johnson
Download or read book Observed Flow Characteristics of Rotating Stall Inception and Its Prevention Using Discrete Tip Injection in the NASA Stage 35 Axial Compressor with New Analysis Methods written by Benjamin P. Johnson and published by . This book was released on 2008 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In order to further our understanding of the effects of tip injection in preventing rotating stall, a number of computational cases were run which modeled stall inception in the NASA compressor Stage 35. The flow solver TURBO, written and developed by Dr. Jen-Ping Chen, was used and new post-processing analysis methods were implemented in these cases. These include the investigation of three-dimensional disturbance (zero axial velocity) pockets, diffusion factor analyses, angle of attack analyses, and negative axial velocity volume measurements. The utilization of these methods led to a number of observations. The first was that the three-dimensional disturbances were first formed in the mid-span of the rotor passages and then migrated to the tip region. Secondly, in both the stable and unstable cases, the disturbances travelled at 100% rotor speed around the annulus upon their inception. The third observation made was that, in stalling cases, the disturbances would eventually occupy the entire breadth of a rotor passage in the vicinity of the tip. Upon this occurrence, the disturbance would begin to propagate upstream of the leading edge of the rotor blade. It would then migrate around the rotor leading edge, merging with the disturbances in the adjacent passages while slowing to approximately 50% rotor speed. The diffusion factor and angle of attack analyses proved less conclusive than had been hoped in providing a definitive, quantitative indication of the inevitability of stall. The original hope was that one or both of these parameters would prove to be a reliable, definitive indicator of the inevitable onset of stall at a given throttle. The diffusion factor analysis provided a means to indicate qualitative differences between different cases, i.e. indicating whether one case is more likely to stall than another. The angle of attack analysis, for the most part, seemed to accurately reflect the actual flow conditions - high angles of attack were recorded for blades which exhibited leading-edge flow separation. Two cases were chosen to represent a stable and stalling case. The results of the stable case indicate that the tip injectors maintain stability in the compressor by preventing the formation of disturbances which occupy the full breadth of a given rotor passage. As the disturbances migrated toward the tip, the injectors would wash them away. To maintain stable operation, some disturbances required passage through the influence of only one injector, while in other cases passage through multiple injectors was required. The results of the unsteady case indicate that if the amount of injection is insufficient, the subsequent merging and growth of the disturbances blocks a significant portion of the rotor face and prevents sufficient mass flow from getting through, resulting in rotating stall.
Book Synopsis A Theory of Rotating Stall of Multistage Axial Compressors by : Franklin K. Moore
Download or read book A Theory of Rotating Stall of Multistage Axial Compressors written by Franklin K. Moore and published by . This book was released on 1983 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Design of Axial-flow Compressors by : Lewis Research Center
Download or read book Aerodynamic Design of Axial-flow Compressors written by Lewis Research Center and published by . This book was released on 1965 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Design of Axial Flow Compressors by : Robert O. Bullock
Download or read book Aerodynamic Design of Axial Flow Compressors written by Robert O. Bullock and published by . This book was released on 1965 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies of End-wall Effects on Rotating Stall Inception in Axial Compressors by : Randy Shek-Ming Chue
Download or read book Studies of End-wall Effects on Rotating Stall Inception in Axial Compressors written by Randy Shek-Ming Chue and published by . This book was released on 1983 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis End-wall Effects on Rotating Stall Inception in Axial Compressors by : Tih-Mei Yuh
Download or read book End-wall Effects on Rotating Stall Inception in Axial Compressors written by Tih-Mei Yuh and published by . This book was released on 1981 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Compressor Surge and Stall by : R. C. Pampreen
Download or read book Compressor Surge and Stall written by R. C. Pampreen and published by . This book was released on 1993 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: High efficiency axial and centrifugal compressors are important in fields as diverse as aircraft engines, superchargers and turbochargers, process and refrigeration compressors. Compressors must achieve high efficiency in blade rows in diffusing flow fields. Of equal and sometimes greater importance is the range os stable operation of the compressor. Blade row stall characteristics determine the limit os stable operation. Blading can stall uniformly with symmetric flow breakdown or asymmetrically in rotating stall, wich propagates around the periphery of the blade row. Depending on aerodynamic conditions, surge may occur instead of, in concert with, or subsequent to blade row stall. The transient breakdown and recovery of aerodynamic loading not only limits compressor performance but also leads to mechanical failures caused by the vibrational loads imposed on the blades. There is no need to know what initiates these performance limits so that surge and stall margins can be optimized and control strategies can be planned. the first step toward understanding is to be knowledgeable about he physical processes occurring during surge and stall. This will permit the designer to anticipate variable geometry needs such as variable inlet guide vanes, variable statuors, and bleed port strategies. Theoritical treatment is far from being well established, however, there are many approaches discussed in the literature. This book is a unique reference to the subject matter. Physical descriptions of the phenomena are given, test results are presented, and analytical studies are discussed. There has been much written about the experimental investigations and theoretical treatments related to surge and stall. To assist those who would pursue advancements in furthering ou knowledge of surge and stall, it seemed appropriate to have a resource that contains a compendium of information on this subject. That is the purpose of this book. [Source : d'après la 4e de couverture].
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721981618 Total Pages :354 pages Book Rating :4.9/5 (816 download)
Book Synopsis Task II by : National Aeronautics and Space Administration (NASA)
Download or read book Task II written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of two types of flow non-uniformity on stall inception behavior were assessed with linearized stability analyses of two compressor flow models. Response to rotating tip clearance asymmetries induced by a whirling rotor shaft or rotor height variations were investigated with a two-dimensional flow model. A 3-D compressor model was also developed to study the stability of both full-span and part-span rotating stall modes in annular geometries with radial flow variations. The studies focussed on (1) understanding what compressor designs were sensitive to these types of circumferential and spanwise flow non-uniformities, and (2) situations where 2-D stability theories were inadequate because of 3-D flow effects. Rotating tip clearance non-uniformity caused the greatest performance loss for shafts whirling at the rotating stall frequency. A whirling shaft displacement of 1 percent chord caused the stalling mass flow to rise by as much as 10 percent and the peak pressure rise to decrease by 6 percent. These changes were an order of magnitude larger than for equivalent-sized stationary or rotor-locked clearance asymmetries. Spanwise flow non-uniformity always destabilized the compressor, so that 2-D models over-predicted that stall margin compared to 3-D theory. The difference increased for compressors with larger spanwise variations of characteristic slope and reduced characteristic curvature near the peak. Differences between 2-D and 3-D stall point predictions were generally unacceptable (2 - 4 percent of flow coefficient) for single-stage configurations, but were less than 1 percent for multistage compressors. 2-D analyses predicted the wrong stall mode for specific cases of radial inlet flow distortion, mismatching and annulus area contraction, where higher-order radial modes led to stall. The stability behavior of flows with circumferential or radial non-uniformity was unified through a single stability criterion. The stall point for both cases was set by...
Book Synopsis Role of Tip Clearance Flow on Axial Compressor Stability by : Huu Duc Vo
Download or read book Role of Tip Clearance Flow on Axial Compressor Stability written by Huu Duc Vo and published by . This book was released on 2001 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: An examination of the fluid dynamic phenomena that link tip clearance flow to the formation of short length-scale (spike) rotating stall disturbances has been carried out. It is found that the onset of growth in tip clearance blockage characterizes the lowest flow coefficient for which a steady blade passage solution exists. It is also found that this condition leads to the formation of spike disturbances. A scenario and criteria for this tip clearance blockage behavior are proposed based on trailing edge backflow and leading edge spillage to the adjacent blade passage. Both are associated with tip clearance flow and occur below the blade tip. Trailing edge backflow involves tip clearance fluid from adjacent blade passages. The leading edge spillage consists of tip clearance fluid from the local blade passage. These two criteria explain the observed length-scale of spike disturbances. This scenario is consistent with several experimental observations on axial compressor stall inception. The implications of these results on the role of single blade passage computations in stall prediction and on the effectiveness of techniques used to delay stall are also discussed.
Book Synopsis Delay of Rotating Stall in Compressors Using Plasma Actuation by : Farzad Ashrafi
Download or read book Delay of Rotating Stall in Compressors Using Plasma Actuation written by Farzad Ashrafi and published by . This book was released on 2014 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotating stall is a well-known aerodynamic instability in compressors that limits the operating envelope of aircraft gas turbine engines. An innovative method for suppressing the most common form of rotating stall inception using an annular DBD plasma actuator had been proposed. A DBD plasma actuator is a simple solid-state device that converts electricity directly into flow acceleration through partial air ionization. However, the proposed concept had only been preliminarily evaluated with simple numerical simulations on an isolated axial rotor using a relatively basic CFD code. The current project provides both an experimental and a numerical assessment of this concept for an axial compressor stage as well as centrifugal compressor stage that are both part of a low-speed two-stage axial-centrifugal compressor test rig. The two configuration studied are the two-stage configuration with a 100 mN/m annular casing plasma actuator placed just upstream of the axial rotor leading edge, and the single-stage centrifugal compressor with the same actuator placed upstream of the impeller leading edge. The tested configuration were simulated with a sophisticated commercial RANS CFD code (ANSYS CFX) in which was implemented the latest engineering DBD plasma model and dynamic throttle boundary condition, using single-passage multiple blade row computational domains. The experiments show that the casing plasma actuator reduces the mass flow of the last stable point (stall point) by 19.28% for the axial compressor stage and 28.39% for the centrifugal compressor stage for which the impeller is the source of rotating stall. The CFD simulations indicate that in both types of compressors the actuator delays the stall inception by pushing the incoming/tip clearance flow interface downstream into the blade passage. In each case, the predicted percentage reduction in stalling mass flow matches the experimental value reasonably well. However, the CFD simulations over-predicts the mass flow of the stall point as well as the pressure rise of the centrifugal stage and under-predict the pressure rise of the axial stage. The main factors for the difference are likely slight discrepancies between the simulated and actual axial rotor blade geometry deformation and the inability of the simulation tool to accurately capture the total pressure loss in the hub region of the vaneless diffuser.
Book Synopsis Investigation of Rotating Stall in Axial Flow Compressors and the Development of a Prototype Rotating Stall Control System by : Gary R. Ludwig
Download or read book Investigation of Rotating Stall in Axial Flow Compressors and the Development of a Prototype Rotating Stall Control System written by Gary R. Ludwig and published by . This book was released on 1973 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report summarizes the results of a three year program on rotating stall in axial flow compressors conducted at Calspan Corporation (formerly Cornell Aeronautical Laboratory). The work encompassed both experimental and theoretical investigations of rotating stall and the development of a prototype rotating stall control system. The experimental portion of the program included investigation of the effects of blade chord and solidity upon rotating stall properties and inception as well as an investigation of the effect of blade row rotation on blade row performance. In addition, an experiment to determine the stability of the flow through a blade row was conducted. A two-dimensional small-disturbance stability theory was developed to predict the inception of rotating stall. A single balde row and two blade row version of the theory were developed.
Download or read book Paper written by and published by . This book was released on 2000 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tip Clearance Flows in Axial Compressors by : Stephanie April Weichert
Download or read book Tip Clearance Flows in Axial Compressors written by Stephanie April Weichert and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The flow in the rotor tip clearance gap in an axial compressor influences the loss levels and the stall onset point. The role of tip clearance flows in the stall inception process is still debated, though. The aim of this thesis is to improve the fundamental understanding of the tip clearance flow field and its role in the stall inception process. The knowledge gained is used to develop a new casing treatment for an aero-engine core compressor. Detailed static pressure, total pressure, and velocity measurements were made in the rotor tip clearance gap at design and near stall flow conditions. The resulting overtip flow maps showed the flow field in more detail than previously possible. Flow variations around the annulus and among blade passages were analyzed and found to increase as stall is approached. This increase was not uniform around the annulus or among passages; instead, some blade passages exhibited unique behaviour compared to all the other passages. The flow variations in the unique passages were linked to small physical irregularities in compressor blading. Detailed overtip measurements were also made at stall inception to investigate the formation of the spike disturbance. These measurements, the first of their kind, showed that the disturbance which initiates the formation of the spike destabilizes the boundary between the reversed flow and incoming flow. After destabilization, reversed flow increasingly dominates the passage until the neighbouring passage is affected. The spike was found to originate most often from those regions in the compressor where the flow variations are highest and was not, as suggested by some research, associated with the forward movement of the tip leakage vortex. A new casing treatment for axial compressors was proposed and tested. The casing treatment extracts air from over the rotor blade tips and re-injects it upstream of the rotor blade leading edges into the tip region through discrete re-circulation loops. The overtip location of air extraction is unique and enables self-regulation of the amount of flow re-circulated: a minimum amount of air is re-circulated at compressor design conditions (thus minimizing any loss of efficiency) and a maximum amount of air is re-circulated near the stability limit (thus maximizing stall margin). Modest stall margin improvements (2%) were achieved without any loss of compressor efficiency at design conditions.
Book Synopsis Computational Fluid Dynamics 2008 by : Haecheon Choi
Download or read book Computational Fluid Dynamics 2008 written by Haecheon Choi and published by Springer Science & Business Media. This book was released on 2009-07-23 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are delighted to present this book which contains the Proceedings of the Fifth International Conference on Computational Fluid Dynamics (ICCFD5), held in Seoul, Korea from July 7 through 11, 2008. The ICCFD series has established itself as the leading international conference series for scientists, mathematicians, and engineers specialized in the computation of fluid flow. In ICCFD5, 5 Invited Lectures and 3 Keynote Lectures were delivered by renowned researchers in the areas of innovative modeling of flow physics, innovative algorithm development for flow simulation, optimization and control, and advanced multidisciplinary - plications. There were a total of 198 contributed abstracts submitted from 25 countries. The executive committee consisting of C. H. Bruneau (France), J. J. Chattot (USA), D. Kwak (USA), N. Satofuka (Japan), and myself, was responsible for selection of papers. Each of the members had a separate subcommittee to carry out the evaluation. As a result of this careful peer review process, 138 papers were accepted for oral presentation and 28 for poster presentation. Among them, 5 (3 oral and 2 poster presentation) papers were withdrawn and 10 (4 oral and 6 poster presentation) papers were not presented. The conference was attended by 201 delegates from 23 countries. The technical aspects of the conference were highly beneficial and informative, while the non-technical aspects were fully enjoyable and memorable. In this book, 3 invited lectures and 1 keynote lecture appear first. Then 99 c- tributed papers are grouped under 21 subject titles which are in alphabetical order.
Book Synopsis Effect of Inlet Temperature on Rotating Stall and Blade Vibrations in a Multistage Axial-flow Compressor by : Arthur A. Medeiros
Download or read book Effect of Inlet Temperature on Rotating Stall and Blade Vibrations in a Multistage Axial-flow Compressor written by Arthur A. Medeiros and published by . This book was released on 1955 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
