Vibration analysis of a test rig for a radial compressor

2001 ◽  
Vol 215 (1) ◽  
pp. 21-29
Author(s):  
S U Lee ◽  
D Robb ◽  
C Besant
Keyword(s):  
High Speed ◽  
Performance Testing ◽  
Operating Conditions ◽  
Fe Model ◽  
Aerodynamic Efficiency ◽  
Radial Compressor ◽  
Turbine Engine ◽  
Compressor Performance ◽  
The Relationship ◽  
Rotor Dynamic

A radial compressor has been designed at Imperial College for cooling a high-speed generator (HSG) coupled directly to a small gas turbine engine to produce 100kW electric power. The compressor has a significant influence on the overall dynamics of the generator. Therefore, it is designed to be lightweight for rotor-dynamic reasons together with reasonable aerodynamic efficiency. An experimental rig for the compressor performance testing was also designed. In order to operate this rig safely, it is very important to be able to predict and analyse its dynamic behaviour. For this purpose, a systematic procedure was used to develop a finite element (FE) model to predict natural frequencies under operating conditions. In the procedure, the relationship between FE analyses, modal analyses and results of a running test are established. Vibration analyses of the compressor rig using the proposed procedure are carried out. Finally, the results of computations and experiments for the rig are presented and compared.

scholarly journals Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Aerospace ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 55 ◽  
Author(s):  
James Large ◽  
Apostolos Pesyridis
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
High Speed ◽  
Engine Performance ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Fan Speed ◽  
Relative Design ◽  
Design Simplicity

In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for its application as propulsion systems for small tactical UAVs (<600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines into turbofans with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving the propulsive performance. The BMT 120 KS micro turbojet engine is selected for the performance evaluation of the conversion process using the gas turbine performance software GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis that is carried out, an improvement in the converted micro gas turbine engine performance, in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, the fan speed operation may be adjusted independently of the core, allowing an increased thrust generation or better fuel consumption. This therefore enables a wider gamut of operating conditions and enhances the performance and scope of the tactical UAV.

Simplified Forced Response HCF Assessment of Turbomachinery Blades

2009 ◽  
Author(s):  
Hans Ma˚rtensson ◽  
Johan Forsman ◽  
Martin Eriksson
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Tangential Force ◽  
Forced Response ◽  
Fe Model ◽  
Compressor Blades ◽  
Design Data ◽  
Modal Force ◽  
Turbomachinery Blades ◽  
Compressor Performance

A method is proposed for HCF-analysis that is suitable for use in early design stages of turbomachinery blades. Quantitative measures of the risk for later encountering HCF life limiting vibrations are the goal for the development. The novelty of the system is the unique and rational way all design data are processed resulting in a mode risk priority listing. The method makes extensive use of FE calculated modal analyses and simple assumptions on the modal force and damping. The modal force is taken proportional to the tangential force on the blade over the operating range. This choice is made because the tangential force is known early on from the compressor performance map, and gives a reasonable scaling with the operating point. Crossings occurring at low speed get a lower force than at high speed. The system damping used is a constant critical damping ratio. Using a modal force and damping along with the FE model forced response amplitude can be directly computed at resonance crossings inside operating envelope. The modal force calculated this way can be compared to the force amplitude needed to reach the fatigue limit in a Haigh diagram. Using the Haigh diagram this way allows modes with localized high stresses, so-called hot spots, to be highlighted. Taking the ratio of the forces gives a ranking value that can be used to compare risk. Details of the technique along with example applications to compressor blades are presented in the paper. It is found that many mode crossings can be excluded as low risk this way and that a rational way of prioritizing is achieved.

Investigation of the axial thrust load using numerical and experimental techniques during turbocharger operation

2017 ◽  
Vol 232 (6) ◽  
pp. 755-765 ◽  
Author(s):  
In-Beom Lee ◽  
Seong-Ki Hong ◽  
Bok-Lok Choi
Keyword(s):  
Axial Force ◽  
Thermal Effects ◽  
High Speed ◽  
Operating Conditions ◽  
Axial Thrust ◽  
Turbine Wheel ◽  
Compressor Wheel ◽  
The Relationship ◽  
Thrust Load ◽  
Calibration Equations

Identification of the axial thrust load during the operating conditions of a turbocharger provides useful information to turbocharger designers. The axial force acting on the thrust bearing is mainly caused by the imbalance between the turbine wheel and the compressor wheel. It has a significant influence on the friction losses, which reduce the efficiency and the performance of a high-speed turbocharger. Well-known formulae for calculating the thrust load and the mechanical friction have been given in the literature. However, it is difficult to determine an accurate axial force by an analytical approach. This paper presents a detailed procedure for prediction of the axial thrust load during turbocharger operation. The first step is to identify the relationship between the externally applied load and the strain response using a specially designed test device and a numerical method. Next, if the operating strains and temperatures are measured, the strain signals due to the axial thrust can be adjusted by subtracting the thermal effects from the measured strains. Finally, the thrust loads in particular operating conditions are inversely obtained by inserting the adjusted strains into the calibration equations.

FE Approach: Electro-Mechanical-Fluid Interaction of Jet Pipe Electrohydraulic Flow Control Servovalve

2003 ◽  
Author(s):  
Somashekhar S. Hiremath ◽  
M. Singaperumal ◽  
R. Krishna Kumar
Keyword(s):  
Steady State ◽  
Force Balance ◽  
Fe Model ◽  
Volume Changes ◽  
New Approach ◽  
Turbine Engine ◽  
Steady State Operation ◽  
Actual Flow ◽  
The Relationship ◽  
Fluid Interaction

Jet pipe electrohydraulic servovalve finds main application in feedback control system working on jet engine and fighter aircrafts. The analyzed jet pipe electrohydraulic servovalve is used in precise fuel control applications in gas turbine engine. This paper gives a new approach for servovalve modeling with the hydrostatic fluid elements in achieve steady state operation. The actual flow required to achieve the force balance is presented analytically. FE model gives the relationship between the spool and jet pipe position in achieving the steady state operation. The spool end cavity volume changes are presented.

Variable Geometry Gas Turbine Radial Compressors

1968 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Performance Testing ◽  
Single Stage ◽  
Variable Geometry ◽  
Pressure Regulation ◽  
Vaned Diffuser ◽  
Radial Compressor ◽  
Flow Variation

An examination of the various mechanical and aerodynamic methods of flow and pressure regulation through high-speed, single-stage radial compressors is presented. Performance testing of a small gas turbine radial compressor with a variable vaned diffuser system is described. Methods of combined geometry variation to obtain minimum reduction of efficiency with flow variation are suggested based upon theoretical matching studies.

Ball Bearing Response to Cage Unbalance

1986 ◽  
Vol 108 (3) ◽  
pp. 462-466 ◽  
Author(s):  
P. K. Gupta ◽  
J. F. Dill ◽  
J. W. Artuso ◽  
N. H. Forster
Keyword(s):  
Entire Range ◽  
High Speed ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Angular Contact Ball Bearing ◽  
Turbine Engine ◽  
Wide Range ◽  
Inner Race ◽  
Good Agreement ◽  
Engine Bearing

Motion of the cage in a high-speed angular contact ball bearing is experimentally investigated as a function of prescribed unbalance, up to operating speeds corresponding to three million DN. The predictions of cage motion made by the recently developed computer model, ADORE, are validated in the light of the experimental data. It is shown the cage whirl velocity is essentially equal to its angular velocity at all levels of unbalance and over a wide range of operating conditions. For the inner race guided turbine engine bearing, the cage/race interaction takes place directly opposite to the location of the unbalance and the severity of the interaction increases with the level of unbalance and the operating speed. ADORE predictions, over the entire range of unbalance and bearing operating conditions, are in very good agreement with the experimental observations.

Flow Investigation Around a V-Sector Ball Valve

2001 ◽  
Vol 123 (3) ◽  
pp. 662-671 ◽  
Author(s):  
P. Merati ◽  
M. J. Macelt ◽  
R. B. Erickson
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Ball Valve ◽  
Operating Conditions ◽  
Mean Velocity ◽  
Model Flow ◽  
Flow Investigation ◽  
And Behavior ◽  
The Relationship

Experimental and computational methods were used to study the structure and behavior of the shedded vortices around a V-ball valve. Strouhal frequency for shedded vortices around the valve over a range of operating conditions and flow rates using water as the medium were measured. The information gathered in this study would help to predict at what operating conditions pipe ruptures might occur. A dynamic pressure transducer was used to determine the Strouhal frequency. LDV was used to measure the mean velocity and turbulence magnitudes. FLUENT was used to develop a two dimensional fluid dynamics model. Flow was visualized using high-speed video photography. A dominant large three-dimensional vortex downstream of the valve was detected. The centerline of this vortex is a shadow of the valve lip. A fifth degree polynomial describing the relationship between the Strouhal number and Reynolds number is obtained.

scholarly journals Leakage and Power Loss Test Results for Competing Turbine Engine Seals

2004 ◽  
Author(s):  
Margaret P. Proctor ◽  
Irebert R. Delgado
Keyword(s):  
High Temperature ◽  
Power Loss ◽  
High Speed ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Test Rig ◽  
Labyrinth Seals ◽  
Turbine Engine

Advanced brush and finger seal technologies offer reduced leakage rates over conventional labyrinth seals used in gas turbine engines. To address engine manufactures’ concerns about the heat generation and power loss from these contacting seals, brush, finger, and labyrinth seals were tested in the NASA High Speed, High Temperature Turbine Seal Test Rig. Leakage and power loss test results are compared for these competing seals for operating conditions up to 922 K (1200 °F) inlet air temperature, 517 KPa (75 psid) across the seal, and surface velocities up to 366 m/s (1200 ft/s).

Aerodynamic Development of a Radial Compressor for a 10-kw Turboalternator

1970 ◽  
Author(s):  
Colin Rodgers
Keyword(s):  
High Speed ◽  
Radial Compressor ◽  
Us Army ◽  
Design Performance ◽  
Performance Requirements ◽  
The Us ◽  
Compressor Performance ◽  
Axial Clearance

The aerodynamic development of a small high-speed radial compressor for the US Army 10-kw turboalternator is discussed, including initial performance deficiencies arising from blade contour discrepancies. Design performance requirements were attained by correcting these discrepancies and subsequently were exceeded with further geometry refinements. Aerodynamic testing included an investigation concerning the effect of shroud axial clearance on compressor performance and showed that abradable shrouds are desirable for small compressors.

scholarly journals Salt-Water Problems in Marine Gas Turbines

1965 ◽  
Author(s):  
Eugene P. Weinert ◽  
Gilbert A. Carlton
Keyword(s):  
Solid State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Salt Water ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Sea Salt ◽  
Turbine Engine ◽  
Compressor Performance ◽  
Water Problems

The gas-turbine engine in naval service is subjected to severe operating conditions. By far the most consistent troublemaker is sea salt. In either liquid or solid state, sea salt causes problems in corrosion of hot and cold surfaces, fouling of fuel systems, and deterioration of compressor performance. Such problems are reviewed and solutions discussed.

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