Experimental Evaluation of an Axial-Flow Transonic Compressor

1976 ◽  
Author(s):  
T. Tamaki ◽  
S. Nagano
Keyword(s):  
Rotational Speed ◽  
Velocity Ratio ◽  
Axial Flow ◽  
Rotating Stall ◽  
Test Results ◽  
Transonic Compressor ◽  
Multi Stage ◽  
Blade Row ◽  
Compressor Surge ◽  
Overall Performance

A five-stage transonic compressor was designed and tested to obtain overall performance and surge limits over a wide rotational speed range. Compressor surge limits are evaluated using individual stage performance characteristics with the aid of a single-stage test. These show that surging at low rotational speed occurs when rotating stall occurs in the first stage and that the wider operating range multi-stage compressor can be realized with the lower aspect ratio blades. On the basis of these test results, a simple model is constructed in order to evaluate the effect of the axial velocity ratio on the flow in a rotor blade row.

scholarly journals Effects of Tip Leakage Flow on the Aerodynamic Performance and Stability of an Axial-Flow Transonic Compressor Stage

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4168
Author(s):  
Botao Zhang ◽  
Xiaochen Mao ◽  
Xiaoxiong Wu ◽  
Bo Liu
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Axial Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Transonic Compressor

To explain the effect of tip leakage flow on the performance of an axial-flow transonic compressor, the compressors with different rotor tip clearances were studied numerically. The results show that as the rotor tip clearance increases, the leakage flow intensity is increased, the shock wave position is moved backward, and the interaction between the tip leakage vortex and shock wave is intensified, while that between the boundary layer and shock wave is weakened. Most of all, the stall mechanisms of the compressors with varying rotor tip clearances are different. The clearance leakage flow is the main cause of the rotating stall under large rotor tip clearance. However, the stall form for the compressor with half of the designed tip clearance is caused by the joint action of the rotor tip stall caused by the leakage flow spillage at the blade leading edge and the whole blade span stall caused by the separation of the boundary layer of the rotor and the stator passage. Within the investigated varied range, when the rotor tip clearance size is half of the design, the compressor performance is improved best, and the peak efficiency and stall margin are increased by 0.2% and 3.5%, respectively.

Reduced-Order Modelling of Rotating Stall

2020 ◽  
Author(s):  
Dominik Schlüter ◽  
Robert P. Grewe ◽  
Fabian Wartzek ◽  
Alexander Liefke ◽  
Jan Werner ◽  
...  
Keyword(s):  
Single Cell ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Stability Limit ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Transonic Compressor ◽  
Experimental Findings

Abstract Rotating stall is a non-axisymmetric disturbance in axial compressors arising at operating conditions beyond the stability limit of a stage. Although well-known, its driving mechanisms determining the number of stall cells and their rotational speed are still marginally understood. Numerical studies applying full-wheel 3D unsteady RANS calculations require weeks per operating point. This paper quantifies the capability of a more feasible quasi-2D approach to reproduce 3D rotating stall and related sensitivities. The first part of the paper deals with the validation of a numerical baseline the simplified model is compared to in detail. Therefore, 3D computations of a state-of-the-art transonic compressor are conducted. At steady conditions the single-passage RANS CFD matches the experimental results within an error of 1% in total pressure ratio and mass flow rate. At stalled conditions, the full-wheel URANS computation shows the same spiketype disturbance as the experiment. However, the CFD underpredicts the stalling point by approximately 7% in mass flow rate. In deep stall, the computational model correctly forecasts a single-cell rotating stall. The stall cell differs by approximately 21% in rotational speed and 18% in circumferential size from the experimental findings. As the 3D model reflects the compressor behaviour sufficiently accurate, it is considered valid for physical investigations. In the second part of the paper, the validated baseline is reduced in radial direction to a quasi-2D domain only resembling the compressor tip area. Four model variations regarding span-wise location and extent are numerically investigated. As the most promising model matches the 3D flow conditions in the rotor tip region, it correctly yields a single-cell rotating stall. The cell differs by only 7% in circumferential size from the 3D results. Due to the impeded radial migration in the quasi-2D slice, however, the cell exhibits an increased axial extent. It is assumed, that the axial expansion into the adjacent rows causes the difference in cell speed by approximately 24%. Further validation of the reduced model against experimental findings reveals, that it correctly reflects the sensitivity of circumferential cell size to flow coefficient and individual cell speed to compressor shaft speed. As the approach reduced the wall clock time by 92%, it can be used to increase the physical understanding of rotating stall at much lower costs.

Excitation of Blade Vibration due to Surge of Centrifugal Compressors

1992 ◽  
Author(s):  
D. Jin ◽  
U. Haupt ◽  
H. Hasemann ◽  
M. Rautenberg
Keyword(s):  
Centrifugal Compressor ◽  
Rotational Speed ◽  
High Performance ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Blade Vibration ◽  
High Rotational Speed ◽  
Blade Thickness ◽  
Periodic Pressure ◽  
Compressor Surge

Centrifugal compressor surge at high rotational speed and reduced blade thickness can produce dangerous excitation effects which have numerous resulted in problems in the past. This paper presents an investigation of blade excitation during surge in a high performance single stage centrifugal compressor with various impeller and diffuser geometry. The blade vibration was measured using blade mounted strain gages. The flow characteristics during surge as the cause of blade excitation were simultaneously determined by fast response dynamic pressure transducers. The experiments have been performed using a radial and a backswept impeller, as well as a vanless and vaned diffusers. The rotational speed of the compressor was varied from 5,000 to 14,500 rpm. The characteristics of unsteady flow during surge, such as, the flow pattern of rotating stall and the non-periodic pressure fluctuation during surge were studied in detail. The experimental results demonstrated that, in addition to the excitation of rotating stall during surge, strong non-periodic pressure fluctuations at the beginning and the end of the surge induced dangerous blade excitations in all compressor configurations. The maximum strain values of blade vibration for all compressor versions at different rotational speeds of the compressor were measured to estimate the danger of blade excitation during surge. The results showed that the blade excitation during compressor surge with vaned diffusers is stronger than the excitation with a vanless diffuser and that the blade excitation with a radial impeller is stronger than the excitation with a backswept impeller.

Analysis of Local Flow Structure and Global Compressor Performance During Rotating Stall

2004 ◽  
Author(s):  
Chiara Palomba
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Rotational Speed ◽  
Axial Flow ◽  
Rotating Stall ◽  
Performance Parameters ◽  
Flow Conditions ◽  
Local Flow ◽  
Flow Parameters ◽  
Compressor Performance

Rotating stall is an instability phenomenon that arises in axial flow compressors when the flow is reduced at constant rotational speed. It is characterised by the onset of rotating perturbations in the flow field accompanied by either an abrupt or gradual decrease of performances. Although the flow field is unsteady and non axisymmetric, the global operating point is stable and a stalled branch of performance curve may be experimentally determined. The number, rotational speed, circumferential extension of the rotating perturbed flow regions named rotating cells may vary from one compressor to another and may depend on the throttle position. The present work focuses on the interaction between local flow parameters and global compressor performance parameters with the aim of reaching a better understanding of the phenomenon. Starting from the Day, Greitzer and Cumpsty [1] model the detailed flow conditions during rotating stall are studied and related to the global performance parameters. This is done both to verify if the compressor under examination fits to the model and if the detailed flow structure may highlight the physics that in the simple model may hide behind the correlation’s used.

Compressor Surge in Gas Turbines and Blast Furnace Compressor Installations

1965 ◽  
Vol 87 (2) ◽  
pp. 193-196
Author(s):  
R. A. Strub ◽  
P. Suter
Keyword(s):  
Fatigue Failure ◽  
Gas Turbines ◽  
Axial Flow ◽  
Rotor Blades ◽  
Test Results ◽  
Dynamic Stresses ◽  
Compressor Surge ◽  
Bending Stresses ◽  
Flow Compressor ◽  
Measured Pressure

The character of different surge cycles is described, and the corresponding influence on the dynamic loading of the blades of axial flow compressors is discussed. It is shown that essentially fatigue is governed by the rapidity of loading or unloading of the blading. Test results from an experimental 4-stage axial flow compressor showed that the induced dynamic stresses in the blades, which reach about three times the steady gas bending stresses, can lead to fatigue failure. Reference is also made to previous surge tests carried out on a gas turbine installation, which indicate that a good correlation can be expected between the calculated and the measured pressure distribution. Mention is made of the fatigue failure of the rotor blades of an industrial compressor submitted to a long period of intense surging.

The Measurement and Interpretation of Flow within Rotating Stall Cells in Axial Compressors

1978 ◽  
Vol 20 (2) ◽  
pp. 101-114 ◽  
Author(s):  
I. J. Day ◽  
N.A. Cumpsty
Keyword(s):  
Flow Direction ◽  
Axial Flow ◽  
Tangential Direction ◽  
Rotating Stall ◽  
Design Flow ◽  
Flow Measurements ◽  
Axial Compressors ◽  
Multi Stage ◽  
Wide Range ◽  
Flow Compressor

Detailed flow measurements obtained by a new measuring technique are presented for the flow in a stalled axial-flow compressor. Results were obtained from a wide range of compressor builds, including multi-stage and single-stage configurations of various design flow rates and degrees of reaction. Instantaneous recordings of absolute velocity, flow direction and total and static pressures have been included for both full-span and part-span stall. With the aid of these results, it has been shown that the conventional model of the flow in a stall cell is erroneous. An alternative model is proposed, based on the observation that the fluid must cross from one side of the cell to the other in order to preserve continuity in the tangential direction. An investigation of the experimental results also reveals the finer details of the flow in the cell and shows how these details are related to the design flow rate of the compressor. The influence of these cell details on the power absorbed by a stalled compressor are investigated, and consideration is given to the complex pressure patterns encountered in the compressor.

Low Reynolds-Number Experiments in an Axial-Flow Turbomachine

1964 ◽  
Vol 86 (3) ◽  
pp. 257-295 ◽  
Author(s):  
J. Neustein
Keyword(s):  
Reynolds Number ◽  
Guide Vane ◽  
Axial Flow ◽  
Reynolds Numbers ◽  
Low Flow ◽  
Working Fluid ◽  
Low Reynolds Numbers ◽  
Blade Row ◽  
Overall Performance ◽  
Low Reynolds

The performance of a single-stage, axial-flow turbomachine was studied experimentally at low Reynolds numbers. The study was made with a turbomachine modeled from a large jet-engine type of axial-flow compressor. Low Reynolds numbers were obtained by using a mixture of glycerine and water as the working fluid. The overall performance was determined over a range of Reynolds numbers RT (based on rotor-tip speed and rotor chord) from 2000 to 150,000. The flow rate at each Reynolds number was varied from near shutoff to the maximum permitted by the turbomachine-tunnel systems. Blade-row characteristics were studied by means of quantitative flow surveys before and after each blade row, and by means of extensive flow-visualization experiments within each blade row. The investigation established that sudden or critical changes in performance do not occur in the type of machine tested, between RT of 150,000 and 20,000. Below 20,000 the performance deteriorated more rapidly. A relatively sharp change in performance occurred between RT of 20,000 and 10,000. The results clarified many of the viscous flow details in each blade row which are associated with the deterioration of performance. These effects were very pronounced at RT of 4000 and below. Consequently, a considerable part of the paper is concerned with results obtained at these lower Reynolds numbers. From the point of view of a designer, information is presented in regard to overall performance, guide-vane turning, and guide-vane and stator total-pressure losses, all as functions of Reynolds number. These results are expected to be indicative of performance in turbomachines similar to the one tested here. Other details are concerned with problems such as wall boundary layers, flow reversal at low flow coefficients, lip-clearance flow, flow patterns near shutoff, and flow comparisons in stators with rotating and stationary hubs.

Experimental investigations on instability evolution in a transonic compressor at different rotor speeds

2015 ◽  
Vol 229 (18) ◽  
pp. 3378-3391 ◽  
Author(s):  
Qiushi Li ◽  
Tianyu Pan ◽  
Tailu Sun ◽  
Zhiping Li ◽  
Yifang Gong
Keyword(s):  
Low Frequency ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Rotor Speed ◽  
Axial Flow Compressor ◽  
Transonic Compressor ◽  
New Type ◽  
Flow Compressor

Experimental investigations are conducted to study the instability evolution in a transonic axial flow compressor at four specific rotor speeds covering both subsonic and transonic operating conditions. Two routes of evolution to final instability are observed in the test compressor: at low rotor speeds, a disturbance in the rotor tip region occurs and then leads to rotating stall, while at high rotor speeds, a low-frequency disturbance in the hub region leads the compressor into instability. Different from stall and surge, this new type of compressor instability at high rotor speed is initiated through the development of a low-frequency axisymmetric disturbance at the hub, and we name it “partial surge”. The frequency of this low-frequency disturbance is approximately the Helmholtz frequency of the system and remains constant during instability inception. Finally, a possible mechanism for the occurrence of different instability evolutions and the formation of partial surge are also discussed.

Multistage Centrifugal Compressor Surge Analysis: Part I — Experimental Investigation

1998 ◽  
Author(s):  
G. L. Arnulfi ◽  
P. Giannattasio ◽  
C. Giusto ◽  
A. F. Massardo ◽  
D. Micheli ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Reference Data ◽  
Dynamic Control ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Multi Stage ◽  
Compressor Surge ◽  
Multistage Centrifugal Compressor ◽  
Insight Into

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and a large plenum discharging into the atmosphere through a throttle valve. Measurements of unsteady pressure and flow rate in the plant, and of instantaneous velocity in the diffusers of the first and fourth compressor stage are performed during deep surge, at several valve settings and three different rotation speeds. Additional tests have been carried out on a different system configuration, i.e., without plenum, in order to obtain the steady-state compressor characteristics and to collect reference data on stall in surge-free conditions. In this configuration, a fully developed rotating stall was detected in the compressor diffusers, while during surge it affects only a limited part of the surge cycle. The goal of the present experimental work was to get a deeper insight into unstable operating conditions of multi-stage centrifugal compressors and to validate a theoretical model of the system instability to be used for the design of dynamic control systems.

Presentation of a Blade-Design Method for Axial-Flow Turbines, Including Design and Test Results of a Typical Axial-Flow Stage

1960 ◽  
Vol 82 (1) ◽  
pp. 19-26
Author(s):  
F. Baumgartner ◽  
R. Amsler
Keyword(s):  
Design Method ◽  
Axial Flow ◽  
Rate Of Change ◽  
Rotor Blades ◽  
Test Results ◽  
Blade Loading ◽  
Blade Row ◽  
Consistent Manner ◽  
The Mean ◽  
Typical Design

A method is presented to determine the shape of stationary nozzle blades and rotor blades for an axial-flow-type turbine in a generally consistent manner based on the concept of aerodynamic blade loading. The mean blade load is a typical design parameter which predominantly determines the blade curvature. It depends in particular on the rate of change of momentum across the blade row. By applying the design method, airfoil shapes are obtained which satisfy the momentum requirements regardless of what blade-load distribution is assumed as long as the mean blade load remains constant. A specific application of the design method is described and test data are presented which show that good agreement between design goal and test results was achieved.

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