Design and Experimental Investigation of a Mixed Flow Supersonic Compressor Stage

1995 ◽  
Author(s):  
Wolfgang Elmendorf ◽  
Harald Kurz ◽  
Heinz E. Gallus
Keyword(s):  
Experimental Investigation ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Strong Shock ◽  
Mixed Flow ◽  
High Pressure Ratio ◽  
Flow Deceleration ◽  
Stage Performance ◽  
Future Demands ◽  
Inlet Conditions

Highly loaded transonic and supersonic compressors appear capable of meeting the future demands of small gas turbines and jet engines. Particularly mixed flow compressors, taking advantage of the increasing circumferential blade speed between rotor inlet and exit, represent a good compromise with regard to high pressure ratio and mass flow on the one hand, and favorable performance characteristics and efficiency on the other. However, operating a supersonic rotor as part of a stage involves a stator characterized by high turning angles, supersonic inlet conditions and a strong flow deceleration. In fact, the stator can be identified as the critical component regarding overall stage performance. Based on experimentally determined rotor exit flow conditions, the first part of this paper describes the design of a tandem stator with a strong shock in the stator entrance region, followed by subsonic flow turning and diffusion. The main thrust of this paper is to present the analytical results obtained in connection with the experimental investigation of the complete stage at design and off-design conditions. Rotor and stator flow as well as the overall stage performance are discussed in detail. The concept of the tandem stator proves to be suitable for managing the extremely high aerodynamic loading in the Stator. Experimental results reveal the design goals to be met in general.

scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2004 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunsheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 feet/sec is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The sensitivity of the stage performance and operability to reduced aspiration flow rates at design and off-design conditions are also discussed.

scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2005 ◽  
Vol 127 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunscheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 ft/s is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The stage performance and operability at reduced aspiration flow rates at design and off-design conditions are also discussed.

Design Study of an Advanced Concept Simple Gas Turbine for Possible Use in Low Emission Automobiles

1972 ◽  
Author(s):  
H. C. Eatock ◽  
M. D. Stoten
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Simple Cycle ◽  
Turbine Engines ◽  
Nox Emissions ◽  
Preliminary Design ◽  
Gas Turbine Engines ◽  
High Pressure Ratio

United Aircraft Corporation studied the potential costs of various possible gas turbine engines which might be used to reduce automobile exhaust emissions. As part of that study, United Aircraft of Canada undertook the preliminary design and performance analysis of high-pressure-ratio nonregenerated (simple cycle) gas turbine engines. For the first time, high levels of single-stage component efficiency are available extending from a pressure ratio less than 4 up to 10 or 12 to 1. As a result, the study showed that the simple-cycle engine may provide satisfactory running costs with significantly lower manufacturing costs and NOx emissions than a regenerated engine. In this paper some features of the preliminary design of both single-shaft and a free power turbine version of this engine are examined. The major component technology assumptions, in particular the high pressure ratio centrifugal compressor, employed for performance extrapolation are explained and compared with current technology. The potential low NOx emissions of the simple-cycle gas turbine compared to regenerative or recuperative gas turbines is discussed. Finally, some of the problems which might be encountered in using this totally different power plant for the conventional automobile are identified.

Health Monitoring of Variable Geometry Gas Turbines for the Canadian Navy

1989 ◽  
Vol 111 (2) ◽  
pp. 244-250 ◽  
Author(s):  
D. E. Muir ◽  
H. I. H. Saravanamuttoo ◽  
D. J. Marshall
Keyword(s):  
Health Monitoring ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Variable Geometry ◽  
Axial Compressors ◽  
High Pressure Ratio ◽  
Department Of National Defence ◽  
Canadian Navy ◽  
General Method

The Canadian Department of National Defence has identified a need for improved Engine Health Monitoring procedures for the new Canadian Patrol Frigate (CPF). The CPF propulsion system includes two General Electric LM2500 gas turbines, a high-pressure-ratio engine with multiple stages of compressor variable geometry. A general method for predicting the thermodynamic performance of variable geometry axial compressors has been developed. The new modeling technique is based on a meanline stage-stacking analysis and relies only on the limited performance data typically made available by engine manufacturers. The method has been applied to the LM2500-30 marine gas turbine and the variations in engine performance that can result from a malfunction of the variable geometry system in service have been estimated.

Dry, Low Emissions for the ‘H’ Heavy-Duty Industrial Gas Turbines: Full-Scale Combustion System Rig Test Results

2003 ◽  
Author(s):  
Geoff Myers ◽  
Dan Tegel ◽  
Markus Feigl ◽  
Fred Setzer ◽  
William Bechtel ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Full Scale ◽  
Combustion System ◽  
Heavy Duty ◽  
Test Program ◽  
Industrial Gas Turbines ◽  
Inlet Conditions

The lean, premixed DLN2.5H combustion system was designed to deliver low NOx emissions from 50% to 100% load in both the Frame 7H (60 Hz) and Frame 9H (50 Hz) heavy-duty industrial gas turbines. The H machines employ steam cooling in the gas turbine, a 23:1 pressure ratio, and are fired at 1440 C (2600 F) to deliver over-all thermal efficiency for the combined-cycle system near 60%. The DLN2.5H combustor is a modular can-type design, with 14 identical chambers used on the 9H machine, and 12 used on the smaller 7H. On a 9H combined-cycle power plant, both the gas turbine and steam turbine are fired using the 14-chamber DLN2.5H combustion system. An extensive full-scale, full-pressure rig test program developed the fuel-staged dry, low emissions combustion system over a period of more than five years. Rig testing required test stand inlet conditions of over 50 kg/s at 500 C and 28 bar, while firing at up to 1440 C, to simulate combustor operation at base load. The combustion test rig simulated gas path geometry from the discharge of the annular tri-passage diffuser through the can-type combustion liner and transition piece, to the inlet of the first stage turbine nozzle. The present paper describes the combustion system, and reports emissions performance and operability results over the gas turbine load and ambient temperature operating range, as measured during the rig test program.

scholarly journals Advanced Labyrinth Seal Design Performance for High Pressure Ratio Gas Turbines

1975 ◽  
Author(s):  
H. L. Stocker
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Labyrinth Seal ◽  
Internal Cavity ◽  
Water Tunnel ◽  
High Pressure Ratio ◽  
Test And Evaluation ◽  
Seal Design ◽  
Dynamic Seal

Labyrinth seal air leakage performance in current and advanced high pressure ratio gas turbines is directly related to the limitations of current available sealing technology. Sea design technology has not kept pace with the gas turbine major component advances. Therefore, an investigation was undertaken to design, fabricate and test several unique labyrinth seal concepts intended to decrease leakage through higher efficiency. The approach used in the unique designs for improving the efficiency of labyrinth seals involved increasing the internal cavity turbulence of the seal. The program involved three test and evaluation phases: (a) water tunnel studies; (b) static air rig tests; and (c) dynamic air rig tests. The water tunnel rig provided an economical method of screening the unique candidate designs. The most promising configurations from the water rig were fabricated and tested in the static air rig. Those configurations demonstrating a significant reduction in seal leakage over current designs were tested dynamically up to 786 ft/sec in an air rig to assess the effects of rotation. The results of this program effort show that each of the unique seal designs achieved lower leakage rates than a standard baseline step seal. In addition the dynamic seal test results show minimal effect on leakage due to rotation up to 786 ft/sec.

Performance of a Mixed Flow Turbocharger Turbine Under Pulsating Flow Conditions

1995 ◽  
Author(s):  
C. Arcoumanis ◽  
I. Hakeem ◽  
L. Khezzar ◽  
R. F. Martinez-Botas ◽  
N. C. Baines
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Pulsating Flow ◽  
Flow Conditions ◽  
Mixed Flow ◽  
Engine Exhaust ◽  
High Pressure Ratio ◽  
Design Speed ◽  
Swallowing Capacity

The performance of a high pressure ratio (P.R.=2.9) mixed flow turbine for an automotive turbocharger has been investigated and the results revealed its better performance relative to a radial-inflow geometry under both steady and pulsating flow conditions. The advantages offered by the constant blade angle rotor allow better turbocharger-engine matching and maximization of the energy extracted from the pulsating engine exhaust gases. In particular, the mixed inlet blade geometry resulted in high efficiency at high expansion ratios where the engine-exhaust pulse energy is maximum. The efficiency characteristics of the mixed flow turbine under steady conditions were found to be fairly uniform when plotted against the velocity ratio, with a peak efficiency at the design speed of 0.75. The unsteady performance as indicated by the mass-averaged total-to-static efficiency and the swallowing capacity exhibited a departure from the quasi-steady assumption which is analysed and discussed.

scholarly journals Optimum Power Boosting of Gas Turbine Cycles With Refrigerated Inlet Air and Compressor Intercooling

1996 ◽  
Author(s):  
Mohand A. Ait-Ali
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Blade Cooling ◽  
High Pressure Ratio ◽  
Blade Cooling ◽  
Air Inlet ◽  
Turbine Inlet ◽  
Compressor Work

With or without turbine blade cooling, gas turbine cycles have consistently higher turbine inlet temperatures than steam turbine cycles. But this advantage is more than offset by the excessive compressor work induced by warm inlet temperatures, particularly during operation on hot summer days. Instead of seeking still higher turbine inlet temperatures by means of sophisticated blade cooling technology and high temperature-resistant blade materials, it is proposed to greatly increase the cycle net work and also improve thermal efficiency by decreasing the compressor work. This is obtained by using refrigerated inlet air and compressor intercooling to an extent which optimizes the refrigerated air inlet temperature and consequently the gas turbine compression ratio with respect to maximum specific net power. The cost effectiveness of this conceptual cycle, which also includes regeneration, has not been examined in this paper as it requires unusually high pressure ratio gas turbines and compressors, as well as high volumetric air flow rate and low temperature refrigeration equipment for which reliable cost data is not easily available.

Numerical Analysis of the Vaned Diffuser of a Transonic Centrifugal Compressor

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Michele Marconcini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Seiichi Ibaraki
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Flow Measurements ◽  
Vaned Diffuser ◽  
High Pressure Ratio ◽  
Unsteady Interaction ◽  
Inlet Conditions

A three-dimensional Navier–Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. Particular attention is focused on the analysis of the vaned diffuser, designed for high subsonic inlet conditions. The diffuser is characterized by a complex three-dimensional flow field and influenced by the unsteady interaction with the impeller. Detailed particle image velocimetry flow measurements within the diffuser are available for comparison purposes.

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