scholarly journals Development of Small Rotating Stall in a Single Stage Axial Compressor

1985 ◽  
Author(s):  
K. Mathioudakis ◽  
F. A. E. Breugelmans
Keyword(s):  
Experimental Study ◽  
Rotor Blade ◽  
Axial Compressor ◽  
Propagation Speed ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Blade Surface ◽  
Hot Wire ◽  
Additional Information ◽  
Cell Pattern

In this paper we present the results of a detailed experimental study of the development of small rotating stall, as it appears in a one stage axial compressor. Stationary hot-wire probes are used to measure the variation of amplitude and propagation speed of the disturbances caused by small stall. Measurements near the rotor blade surface with rotating probes provide additional information on the nature of the phenomenon. The development of the cell pattern for different operating conditions is studied. The different character from what is known as “big stall” is demonstrated.

Cold Blade Profile Generation Methodology for Compressor Rotor Blades Using FSI Approach

2017 ◽  
Author(s):  
Kirubakaran Purushothaman ◽  
Sankar Kumar Jeyaraman ◽  
Ajay Pratap ◽  
Kishore Prasad Deshkulkarni
Keyword(s):  
Aspect Ratio ◽  
Rotor Blade ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Blade Profile ◽  
Interaction Technique ◽  
Compressor Rotor ◽  
Blade Shape ◽  
Blade Geometry

This paper describes a methodology for obtaining correct blade geometry of high aspect ratio axial compressor blades during running condition taking into account of blade untwist and bending. It discusses the detailed approach for generating cold blade geometry for axial compressor rotor blades from the design blade geometry using fluid structure interaction technique. Cold blade geometry represents the rotor blade shape at rest, which under running condition deflects and takes a new operating blade shape under centrifugal and aerodynamic loads. Aerodynamic performance of compressor primarily depends on this operating rotor blade shape. At design point it is expected to have the operating blade shape same as the intended design blade geometry and a slight mismatch will result in severe performance deterioration. Starting from design blade profile, an appropriate cold blade profile is generated by applying proper lean and pre-twist calculated using this methodology. Further improvements were carried out to arrive at the cold blade profile to match the stagger of design profile at design operating conditions with lower deflection and stress for first stage rotor blade. In rear stages, thermal effects will contribute more towards blade deflection values. But due to short blade span, deflection and untwist values will be of lower values. Hence difference between cold blade and design blade profile would be small. This methodology can especially be used for front stage compressor rotor blades for which aspect ratio is higher and deflections are large.

Investigation of Unsteady Aerodynamic Blade Excitation Mechanisms in Transonic Turbine Stages

2002 ◽  
Author(s):  
Bjo¨rn Laumert ◽  
Hans Ma˚rtensson ◽  
Torsten H. Fransson
Keyword(s):  
Rotor Blade ◽  
Three Dimensional ◽  
Relative Strength ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Pressure Perturbation ◽  
Blade Surface ◽  
Excitation Mechanisms ◽  
Transonic Turbine ◽  
Exit Mach Number

This paper presents a study of the blade pressure perturbation levels and the resulting rotor blade force in three high-pressure transonic turbine stages, based on three-dimensional unsteady viscous computations. The aim is to identify stage characteristics that correlate with the perturbation strength and degree of force realization on the rotor blades. To address the effects of off-design operation, the computations were performed at high subsonic, design and higher vane exit Mach number operating conditions. Furthermore spanwise variations in pressure levels and blade force are addressed. In our investigation the RMS of the pressure perturbations integrated in both time and along the blade surface is utilized as a global measure of the blade pressure perturbation strength on the rotor blade surface. The relative strength of the different pressure perturbation events on the rotor blade surface is also investigated. To obtain information about the relative strength of events related to the blade passing frequency the pressure field is Fourier decomposed in time at different radial positions along the blade arc-length. With the help of the observations and results from the blade pressure study, the radial variations of the unsteady blade force are addressed.

Dynamic Characterization and Identification of Flow in a Blade Passage in Near-Stall Conditions of Axial Compressor Systems

2019 ◽  
Author(s):  
Eighdi Aung ◽  
Marco P. Schoen ◽  
Jichao Li
Keyword(s):  
Correlation Coefficient ◽  
Active Flow Control ◽  
Axial Compressor ◽  
Leading Edge ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Sensor Data ◽  
Detection Methods ◽  
Operating Point ◽  
Stall Inception

Abstract Axial compressor systems are susceptible to unstable conditions near their optimal operating point. In particular, rotating stall and surge are conditions that need to be avoided during the operation of an axial compressor. In extreme cases these conditions may cause damage to the compressor. The onset of either condition is rather rapid, and usually does not allow for remedial control action based on the limited time available. Hence, research efforts have been focusing on the development of new detection methods that allow for more time to take corrective measures. This paper explores and compares various existing and proposed methods to identify and detect those precursors. The methods detailed in this work are tested at different operating conditions and locations. The methods investigated include the sequentially computed correlation coefficient of pressure sensor data, correlation coefficient, the Generalized Extreme Studentized Deviate Test (ESD) for outlier detection, spectral entropy, and Autoregressive (AR) models. The primary goal of evaluating these methods is based on their suitability for employment as pre-processors for dynamic system identification. By using the dynamics of the identified model rather than a static precursor, it is stipulated that the onset of stall and surge can be managed with a control concept. For this work, the extracted models are investigated for suitability to serve as precursors, and the potential as predictive models. This work may serve for future work to achieve active flow control by direct air injection at the leading edge of the blades. For this work, a one-stage compressor system with a blade geometry that allows for spike inception is utilized. Spike stall inception is a precursor to fully developed rotating stall. The subsonic compressor has 60 blades, and its operating point is controlled by a throttle and constant speed control of the rotor. The pressure data is collected with 10 Kulite™ sensors which are placed along the blade cord length on the outer casing of the compressor. The results of the tabulated performance of the various methods and resulting models indicate that an ARESD combination yields the earliest indication for spike stall inception.

Structure and Propagation of Rotating Stall in a Single- and a Multi-Stage Axial Compressor

1999 ◽  
Author(s):  
H. M. Saxer-Felici ◽  
A. P. Saxer ◽  
F. Ginter ◽  
A. Inderbitzin ◽  
G. Gyarmathy
Keyword(s):  
Numerical Solutions ◽  
Equations Of Motion ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Water Model ◽  
Two Stage ◽  
Additional Information ◽  
Driving Mechanisms ◽  
Multi Stage ◽  
Stall Cells

The structure and propagation of rotating stall cells in a single- and a two-stage subsonic axial compressor is addressed in this paper using computational and experimental analysis. Unsteady solutions of the 2-D inviscid compressible (Euler) equations of motion are presented for one operating point in the fully-developed rotating stall regime for both a single- and a two-stage compressor. The inviscid assumption is verified by comparing the single-stage 2-D in viscid/compressible solution with an equivalent 2-D viscous (Navier-Stokes) result for incompressible flow. The structure of the rotating stall cell is analyzed and compared for the single- and two-stage cases. The numerical solutions are validated against experimental data consisting of flow visualization and unsteady row-by-row static pressure measurements obtained in a four-stage water model of a subsonic compressor. The CFD solutions supply a link between the observed experimental features and provide additional information on the structure of the stall flow. Based on this study. supporting assumptions regarding the driving mechanisms for the propagation of fully-developed rotating stall cells and their structure are postulated. In methodical respect the results suggest that the inviscid model is able to reproduce the essentials of the flow physics associated with the propagation of fully-developed, full-span rotating stall in a subsonic axial compressor.

Noise generation in vane axial fans due to rotating stall and surge

2001 ◽  
Vol 215 (1) ◽  
pp. 57-64 ◽  
Author(s):  
M Čudina
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Noise Generation ◽  
Total Noise ◽  
Operating Stability ◽  
Partial Load ◽  
Axial Fans

A characteristic of axial flow fans is instabilities in their performance and noise in partial load operation. These instabilities are a consequence of rotating stall created in the rotor blade and/or in the guide vane cascade. At some operating conditions the rotating stall caused the appearance of a surge representing the lowest region of fan operating stability. The rotating stall and especially surge caused a steep increase in the emitted noise and lowered the performance of the fan. The present paper highlights the rotating stall generation phenomenon and its influence on the emitted total noise level and noise spectra for axial flow fans with inlet and outlet guide vanes.

Velocity Measurements Downstream of the Impellers in a Multistage Centrifugal Blower

1994 ◽  
Author(s):  
G. L. Amulfi ◽  
D. Micheli ◽  
P. Pinamonti
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Flow Rate ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Field Analysis ◽  
Test Plant ◽  
Hot Wire ◽  
Centrifugal Blower ◽  
Ensemble Averaging

The paper presents the results of an experimental investigation on a four-stage centrifugal blower, having the aim of obtaining an accurate description of the flow field behind the impellers in several operative conditions and for different geometrical configurations. Actually, the test plant allows to change the turbomachinery characteristics assembling one, two, three or four stages and three different types of diffusers. In this first research step, the blower has been tested in the four-stage vaneless diffuser configuration. The unsteady flow field behind the impellers and in the diffusers has been measured by means of a hot-wire anemometer. A Phase Locked Ensemble Averaging Technique has been utilised to obtain the relative flow field from the instantaneous signals of the stationary hot-wire probes. Several detailed measurements sets have been performed using both single and crossed hot-wire probe, to obtain the velocity vectors and turbulence trends, just behind the blower impellers and in several radial positions of the vaneless diffusers. These measurements have been done at different flow rate conditions, covering unsteady flow rate phenomena (rotating stall) too. The results obtained allowed to get a detailed flow field analysis in the multistage centrifugal blower, in relation to the geometrical configuration and to the differing operating conditions.

Numerical and experimental study of rotating stall in an axial compressor stage

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1132-1141 ◽  
Author(s):  
Helene M. Saxer-Felici ◽  
Andre P. Saxer ◽  
Andreas Inderbitzin ◽  
George Gyarmathy
Keyword(s):  
Experimental Study ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Compressor Stage

Numerical and Experimental Study of Rotating Stall in an Axial Compressor Stage

AIAA Journal ◽  
2000 ◽  
Vol 38 (7) ◽  
pp. 1132-1141 ◽  
Author(s):  
Helene M. Saxer-Felici ◽  
Andre P. Saxer ◽  
Andreas Inderbitzin ◽  
George Gyarmathy
Keyword(s):  
Experimental Study ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Compressor Stage

scholarly journals Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors

2014 ◽  
Author(s):  
Klaus Brun ◽  
William C. Foiles ◽  
Terrence A. Grimley ◽  
Rainer Kurz
Keyword(s):  
Wind Tunnel ◽  
Gas Turbine ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Blade Surface ◽  
Compressor Blades ◽  
Flow Recirculation ◽  
Water Washing ◽  
Air Stream ◽  
Recirculation Zones

An investigation of the effectiveness of online combustion turbine axial compressor washing using various purity grade waters and commercial washing detergents was performed. For this project, blade surface fouling dirt was obtained from gas turbine axial compressor blades installed at various field sites. The dirt was analyzed to determine the composition and consistency of typical blade surface fouling materials. A representative dirt formula and blade coating procedure was developed so that comparative tests could be performed using various cleaning fluids. Dirt coated blades were installed in a wind tunnel capable of simulating compressor operating conditions. A spray nozzle upstream of the blade test section was used for washing blades with five different test liquids to determine the effectiveness or advantages of any liquid. Once this testing was completed, a similar test setup was then utilized to inject a mixture of formulated fouling dirt and the various online cleaning liquids upstream of the blade into the wind tunnel to assess redeposit characteristics. The effect of high-purity water versus regular water on fouling dirt was also studied in separate residue experiments. Results indicate that spraying cleaning fluid into a flowing air stream is a viable means of cleaning a compressor blade. Each of the fluids was able to clean the test blade at both low and high air velocities and at different blade incident angles. Within the parameters/fluids tested, the results indicate that: 1. The blade cleaning is primarily a mechanical function and does not depend on the type of fluid used for cleaning. The results showed that most of the cleaning occurs shortly after the cleaning fluid is introduced into the flow stream. 2. Dirt removed from the blades may redeposit in other areas as the cleaning fluid is evaporated. Redeposit occurred in flow recirculation zones during the cleaning tests, and heated flow tests demonstrated dirt deposit in the presence of a cleaning fluid. In addition, the type of fluid used for cleaning has no effect on the redeposit characteristics of the dirt. 3. Blade erosion was not found to be a significant issue for the short durations that online water-washing was performed. However, uncontrolled water-washing (or overspray) for extended periods of time did result in measureable leading and trailing edge blade erosions.

Examination of Rotating Stall Inception in a Small High Speed Axial Compressor

2009 ◽  
Author(s):  
L. G. N. Bennett ◽  
W. D. E. Allan
Keyword(s):  
High Speed ◽  
Gasoline Engine ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Pressure Measurements ◽  
Operating Life ◽  
Fourier Decomposition ◽  
Stall Inception ◽  
Prediction And Prevention

Rotating stall is an internal aerodynamic disturbance that limits the performance and operating life of a compressor. It has been studied with the aim of developing techniques for its prediction and prevention. To further the understanding of rotating stall inception, a test rig was constructed with the axial stages of a Rolls Royce Model 250-C20B small, high speed axial compressor as the test article. A gasoline engine was used to power the compressor and airflow was throttled through a pneumatically controlled valve. Simultaneous static pressure measurements were taken with seven high speed transducers arranged in two configurations: distributed both axially and circumferentially around the compressor casing. The compressor characteristic was mapped and detailed pressure measurements were taken between normal and surge operating conditions. Previous studies of high speed multi-stage compressors have shown both modal and spike type stall inception at different compressor stages. Other examinations of the Model 250 compressor have shown stall inception occurring at the first stage of the compressor. Similar results were observed in this study and an analysis was conducted using a variety of signal processing techniques including pressure trace inspection and discrete spatial Fourier decomposition.

Sign in / Sign up

Export Citation Format

Share Document