scholarly journals Experimental Investigation of Axial-Flow Compressors with Large Flow Coefficient : Especially on the Comparison of High Speed and Low Speed Test Results

1966 ◽  
Vol 32 (234) ◽  
pp. 288-301
Author(s):  
Takesi SIRATO ◽  
Takesi YAMANE ◽  
Tetumasa YAMANE
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Test Results ◽  
Low Speed ◽  
Speed Test ◽  
Large Flow ◽  
Axial Flow Compressors

Loss Reduction in Axial-Flow Compressors Through Low-Speed Model Testing

1985 ◽  
Vol 107 (2) ◽  
pp. 354-363 ◽  
Author(s):  
D. C. Wisler
Keyword(s):  
Flow Separation ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Secondary Flows ◽  
Stall Margin ◽  
Low Speed ◽  
High Loss ◽  
Aerodynamic Model ◽  
Axial Flow Compressors

A systematic procedure for reducing losses in axial-flow compressors is presented. In this procedure, a large, low-speed, aerodynamic model of a high-speed core compressor is designed and fabricated based on aerodynamic similarity principles. This model is then tested at low speed where high-loss regions associated with three-dimensional endwall boundary layers, flow separation, leakage, and secondary flows can be located, detailed measurements made, and loss mechanisms determined with much greater accuracy and much lower cost and risk than is possible in small, high-speed compressors. Design modifications are made by using custom-tailored airfoils and vector diagrams, airfoil endbends, and modified wall geometries in the high-loss regions. The design improvements resulting in reduced loss or increased stall margin are then scaled to high speed. This paper describes the procedure and presents experimental results to show that in some cases endwall loss has been reduced by as much as 10 percent, flow separation has been reduced or eliminated, and stall margin has been substantially improved by using these techniques.

Mixing in Axial Flow Compressors: Part I — Test Facilities and Measurements in a Four-Stage Compressor

1990 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Two Dimensional ◽  
Similar Magnitude ◽  
Low Speed ◽  
The Third ◽  
Mixing Coefficients ◽  
Experimental Facilities ◽  
Axial Flow Compressors

The mechanism of mixing in axial flow compressors has been investigated in two low speed machines. For reasons of length this is described in two parts. Results in a 4-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.

Improved criteria for stall-free preliminary design of axial compressor of aero gas turbine engines

2018 ◽  
Vol 233 (9) ◽  
pp. 3286-3297 ◽  
Author(s):  
MR Aligoodarz ◽  
A Mehrpanahi ◽  
M Moshtaghzadeh ◽  
A Hashiehbaf
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Axial Compressor ◽  
Axial Flow ◽  
Design Criterion ◽  
Flow Coefficient ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Parameter Ranges ◽  
Axial Flow Compressors

A worldwide effort has been devoted to developing highly efficient and reliable gas turbine engines. There exist many prominent factors in the development of these engines. One of the most important features of the optimal design of axial flow compressors is satisfying the allowable range for various parameters such as flow coefficient, stage loading, the degree of reaction, De-Haller number, etc. But, there are some applicable cases that the mentioned criteria are exceeded. One of the most famous parameters is De-Haller number, which according to literature data should not be kept less than 0.72 in any stage of the axial compressor. A deep insight into the current small- or large-scale axial flow compressors shows that a discrepancy will occur among design criterion for De-Haller number and experimental measurements in which the De-Haller number is less than the design limit but no stall or surge is observed. In this paper, an improved formulation is derived based on one-dimensional modeling for predicting the stall-free design parameter ranges especially stage loading, flow coefficient, etc. for various combinations. It was found that the current criterion is much more accurate than the De-Haller criterion for design purposes.

Modelling the Axial-Flow Compressors for Calculating Starting of Turbojet Engines

1985 ◽  
Author(s):  
Yan De-You
Keyword(s):  
Excellent Agreement ◽  
Axial Flow ◽  
Structural Formula ◽  
Experimental Results ◽  
Low Speed ◽  
Structural Formulae ◽  
Axial Flow Compressors

This paper provides a method of modelling the axial-flow compressors in the low speed starting regime of an engine from windmilling to idling. A structural formula for the model is established by means of reference (1). A method of step-by-step regression is provided by the author for determining the coefficient matrices of the structural formulae. Excellent agreement was obtained between the computational and experimental results.

Mixing in Axial Flow Compressors: Part I—Test Facilities and Measurements in a Four-Stage Compressor

1991 ◽  
Vol 113 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Y. S. Li ◽  
N. A. Cumpsty
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Two Dimensional ◽  
Similar Magnitude ◽  
Low Speed ◽  
The Third ◽  
Mixing Coefficients ◽  
Experimental Facilities ◽  
Axial Flow Compressors

The mechanism of mixing in axial flow compressors has been investigated in two low-speed machines. For reasons of length this is described in two parts. Results in a four-stage compressor are described here in Part I and show that the mixing coefficients across the first and the third stators are of similar magnitude. Part I also describes the background and experimental facilities and techniques used in both parts together with the nomenclature and all the references. Part II describes the results from a large single-stage compressor. It also presents measurements of mixing in a simple two-dimensional duct, and presents conclusions for the whole investigation.

The Use of Sweep and Dihedral in Multistage Axial Flow Compressor Blading: Part I — University Research and Methods Development

2002 ◽  
Author(s):  
Simon J. Gallimore ◽  
John J. Bolger ◽  
Nicholas A. Cumpsty ◽  
Mark J. Taylor ◽  
Peter I. Wright ◽  
...  
Keyword(s):  
High Speed ◽  
Axial Flow ◽  
Essential Element ◽  
University Research ◽  
Low Speed ◽  
High Speed Engine ◽  
Methods Development ◽  
Basic Ideas ◽  
Flow Compressor ◽  
The University

This paper describes the introduction of 3D blade designs into the core compressors for the Rolls-Royce Trent engine with particular emphasis on the use of sweep and dihedral in the rotor designs. It follows the development of the basic ideas in a university research project, through multistage low-speed model testing, to the application to high pressure engine compressors. An essential element of the project was the use of multistage CFD and some of the development of the method to allow the designs to take place is also discussed. The first part of the paper concentrates on the university-based research and the methods development. The second part describes additional low-speed multistage design and testing and the high-speed engine compressor design and test.

Low speed test results of subsonic, turbofan scarf inlets

1993 ◽  
Author(s):  
T. CRUM ◽  
D. YATES ◽  
T. ANDREW ◽  
N. STOCKMAN
Keyword(s):  
Test Results ◽  
Low Speed ◽  
Speed Test

Experimental Investigation of Low Speed Disc Brake Judder Vibration

2013 ◽  
Vol 471 ◽  
pp. 25-29
Author(s):  
Mohd Razmi Ishak ◽  
Abd Rahim Abu Bakar ◽  
Subki Shamsudin ◽  
Muhammad Husaini Maskak ◽  
Mohd Kameil Abdul Hamid
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Axial Direction ◽  
Comfort Level ◽  
Steering Wheel ◽  
Disc Brake ◽  
Test Rig ◽  
Low Speed ◽  
Suspension Systems ◽  
Wheel Turning

Brake judder is defined as disc or drum deformation-induced vibration which typically occurs at frequency less than 200 Hz. There are two types of brake judder namely, low speed (cold) judder and high speed (hot) judder. These two types of judder are often causing the brake pedal, steering wheel, suspension or chassis to vibrate. Consequently, it will affect comfort level of the driver and passengers. This paper focuses on the experimental investigation of low speed brake judder. In doing so, a laboratory test rig consists of disc brake unit, steering and suspension systems was used to assess level of brake judder vibration at different wheel turning angles. It was found that brake judder generated slightly high vibration at the steering wheel in the axial direction which led to a little uncomfortable feeling to the driver.

Turbomachinery Committee Best 1994 Paper Award: Dynamic Control of Rotating Stall in Axial Flow Compressors Using Aeromechanical Feedback

1995 ◽  
Vol 117 (3) ◽  
pp. 307-319 ◽  
Author(s):  
D. L. Gysling ◽  
E. M. Greitzer
Keyword(s):  
Control Strategy ◽  
Dynamic Control ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Compression System ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Axial Flow Compressors

Dynamic control of rotating stall in an axial flow compressor has been implemented using aeromechanical feedback. The control strategy developed used an array of wall jets, upstream of a single-stage compressor, which were regulated by locally reacting reed valves. These reed valves responded to the small-amplitude flow-field pressure perturbations that precede rotating stall. The valve design was such that the combined system, compressor plus reed valve controller, was stable under operating conditions that had been unstable without feedback. A 10 percent decrease in the stalling flow coefficient was obtained using the control strategy, and the extension of stable flow range was achieved with no measurable change in the steady-state performance of the compression system. The experiments demonstrate the first use of aeromechanical feedback to extend the stable operating range of an axial flow compressor, and the first use of local feedback and dynamic compensation techniques to suppress rotating stall. The design of the experiment was based on a two-dimensional stall inception model, which incorporated the effect of the aeromechanical feedback. The physical mechanism for rotating stall in axial flow compressors was examined with focus on the role of dynamic feedback in stabilizing compression system instability. As predicted and experimentally demonstrated, the effectiveness of the aeromechanical control strategy depends on a set of nondimensional control parameters that determine the interaction of the control strategy and the rotating stall dynamics.

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