An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV
Author :
Publisher :
Page : 30 pages
File Size : 45,34 MB
Release : 2002
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ISBN :
An Investigation of Surge in a High-speed Centrifugal Compressor Using Digital Piv
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 28 pages
File Size : 16,12 MB
Release : 2018-08-27
Category :
ISBN : 9781726206143
Book Description
Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to successfully control these events. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to simultaneously capture transient velocity and pressure measurements in the non-stationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique which is ideally suited for studying transient flow phenomena in high speed turbomachinery and has been used previously to successfully map the stable operating point flow field in the diffuser of a high speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.Wernet, Mark P. and Bright, Michelle M. and Skoch, Gary J.Glenn Research CenterCENTRIFUGAL COMPRESSORS; ROTATING STALLS; PARTICLE IMAGE VELOCIMETRY; PRESSURE MEASUREMENT; DYNAMIC PRESSURE; PRESSURE SENSORS; TRANSIENT PRESSURES; UNSTEADY FLOW...
Experimental Investigation of Centrifugal Compressor Stabilization Techniques
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 32 pages
File Size : 23,84 MB
Release : 2018-06-21
Category :
ISBN : 9781721640812
Book Description
Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points. Skoch, Gary J. Glenn Research Center NASA/TM-2003-212599, E-14156, ARL-TR-2921, GT-2003-38524
Analysis of Dynamic Inlet Distortion Applied to a Parallel Compressor Model
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 26 pages
File Size : 35,63 MB
Release : 2018-07-20
Category :
ISBN : 9781723255342
Book Description
An investigation of surge was conducted by using a parallel compressor model of the J85-13 compressor implement on an analog computer. Surges were initiated by various types of dynamic disturbances in inlet pressure. The compressor model was less sensitive to disturbances of short duration, high frequency, and long duration where the compressor discharge pressure could react. Adding steady distortion to dynamic disturbances reduced the amount of dynamic disturbance required to effect surge. Steady and unsteady distortions combined linearly to reduce surge margin. Wenzel, L. M. and Blaha, R. J. Glenn Research Center NASA-TM-X-3522, E-8979 RTOP 505-05
Experimental Investigation of Diffuser Hub Injection to Improve Centrifugal Compressor Stability
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 24 pages
File Size : 29,14 MB
Release : 2018-06-21
Category :
ISBN : 9781721676873
Book Description
Results from a series of experiments to investigate whether centrifugal compressor stability could be improved by injecting air through the diffuser hub surface are reported. The research was conducted in a 4:1 pressure ratio centrifugal compressor configured with a vane-island diffuser. Injector nozzles were located just upstream of the leading edge of the diffuser vanes. Nozzle orientations were set to produce injected streams angled at 8, 0 and +8 degrees relative to the vane mean camber line. Several injection flow rates were tested using both an external air supply and recirculation from the diffuser exit. Compressor flow range did not improve at any injection flow rate that was tested. Compressor flow range did improve slightly at zero injection due to the flow resistance created by injector openings on the hub surface. Leading edge loading and semi-vaneless space diffusion showed trends similar to those reported earlier from shroud surface experiments that did improve compressor flow range. Opposite trends are seen for hub injection cases where compressor flow range decreased. The hub injection data further explain the range improvement provided by shroud-side injection and suggest that different hub-side techniques may produce range improvement in centrifugal compressors. Skoch, Gary J. Glenn Research Center NASA/TM-2004-213182, ARL-TR-3158, GT2004-53618, E-14677
A Prediction of 3-D Viscous Flow and Performance of the NASA Low-Speed Centrifugal Compressor
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 66 pages
File Size : 42,24 MB
Release : 2018-07-02
Category :
ISBN : 9781722141974
Book Description
A prediction of the 3-D turbulent flow in the NASA Low-Speed Centrifugal Compressor Impeller has been made. The calculation was made for the compressor design conditions with the specified uniform tip clearance gap. The predicted performance is significantly worse than that predicted in the NASA design study. This is explained by the high tip leakage flow in the present calculation and by the different model adopted for tip leakage flow mixing. The calculation gives an accumulation for high losses in the shroud/pressure-side quadrant near the exit of the impeller. It also predicts a region of meridional backflow near the shroud wall. Both of these flow features should be extensive enough in the NASA impeller to allow detailed flow measurements, leading to improved flow modelling. Recommendations are made for future flow studies in the NASA impeller. Moore, John and Moore, Joan G. Unspecified Center...
Self-Recirculating Casing Treatment Concept for Enhanced Compressor Performance
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 30 pages
File Size : 48,72 MB
Release : 2018-06-19
Category :
ISBN : 9781721513901
Book Description
A state-of-the-art CFD code (APNASA) was employed in a computationally based investigation of the impact of casing bleed and injection on the stability and performance of a moderate speed fan rotor wherein the stalling mass flow is controlled by tip flow field breakdown. The investigation was guided by observed trends in endwall flow characteristics (e.g., increasing endwall aerodynamic blockage) as stall is approached and based on the hypothesis that application of bleed or injection can mitigate these trends. The "best" bleed and injection configurations were then combined to yield a self-recirculating casing treatment concept. The results of this investigation yielded: 1) identification of the fluid mechanisms which precipitate stall of tip critical blade rows, and 2) an approach to recirculated casing treatment which results in increased compressor stall range with minimal or no loss in efficiency. Subsequent application of this approach to a high speed transonic rotor successfully yielded significant improvements in stall range with no loss in compressor efficiency. Hathaway, Michael D. Glenn Research Center NASA/TM-2002-211569, E-13353, NAS 1.15:211569, ARL-TR-2748, GT-2002-30368
Analytical Prediction of the Performance and Stability of a J85-13 Compressor with Distorted Inlet Flow
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 32 pages
File Size : 49,63 MB
Release : 2018-07-25
Category :
ISBN : 9781724242174
Book Description
The parallel compressor concept was studied using a compressor model based on the overall clean-inlet performance map obtained from experimental tests in an altitude chamber using a General Electric J85-13 turbojet engine. The model, which includes a static-pressure balance calculation at compressor discharge, was exercised at conditions corresponding to 10 different screen-induced distortion patterns included in the experimental data base. The spoiled area of these patterns ranged from 30 deg to 180 deg, and the distortion screen density, or the area blocked by the screen wire per unit area of screen, varied from 26 to 69 percent. The study indicates that at the higher corrected speeds, the analytical surge lines obtained are good representations of the corresponding experimental surge lines and are independent of distortion angle or distortion angle or distortion level. Milner, E. J. Glenn Research Center NASA-TM-X-3515, E-8887 RTOP 505-05
Experimental Performance of a 16.10-Centimeter-Tip-Diameter Sweptback Centrifugal Compressor Designed for a 6
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 34 pages
File Size : 42,54 MB
Release : 2018-08-09
Category :
ISBN : 9781724979667
Book Description
A backswept impeller with design mass flow rate of 1.033 kg/sec was tested with both a vaned diffuser and a vaneless diffuser to establish stage and impeller characteristics. Design stage pressure ratio of 5.9:1 was attained at a flow slightly lower than the design value. Flow range at design speed was 6 percent of choking flow. Impeller axial tip clearance at design speed was varied to determine effect on stage and impeller performance. Klassen, H. A. and Wood, J. R. and Schumann, L. F. Glenn Research Center NASA-TM-X-3552, E-9074 RTOP 505-04...
Comparisons of Rig and Engine Dynamic Events in the Compressor of an Axi-Centrifugal Turboshaft Engine
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 28 pages
File Size : 24,99 MB
Release : 2018-08-16
Category :
ISBN : 9781725578500
Book Description
Steady state and dynamic data were acquired in a T55-L-712 compressor rig. In addition, a T55-L-12 engine was instrumented and similar data were acquired. Rig and engine stall/surge data were analyzed using modal techniques. This paper compares rig and engine preliminary results for the ground idle (approximately 60% of design speed) point. The results of these analyses indicate both rig and engine dynamic event are preceded by indications of traveling wave energy in front of the compressor face. For both rig and engine, the traveling wave energy contains broad band energy with some prominent narrow peaks and, while the events are similar in many ways, some noticeable differences exist between the results of the analyses of rig data and engine data. Owen, A. Karl and Mattern, Duane L. and Le, Dzu K. Glenn Research Center NASA-TM-107339, NAS 1.15:107339, ASME-96-GT-239, ARL-TR-1108, E-10478 RTOP 505-62-0L...
