Wet Compression Effects on Axial Compressor Performance Using Pitch-Line Models

2010 ◽  
Author(s):  
Arathi K. Gopinath ◽  
Giridhar Jothiprasad ◽  
Trevor Wood ◽  
Le Tran
Keyword(s):  
Axial Compressor ◽  
Water Evaporation ◽  
Performance Predictions ◽  
Blade Row ◽  
Compressor Inlet ◽  
Droplet Sizes ◽  
Compressor Performance ◽  
Wet Compression ◽  
Compression Effects ◽  
The Impact

The impact of wet compression technology on compressor performance is studied using a coupled water-evaporation-pitch-line numerical model. The model uses an iterative approach to compute the modified flow conditions at blade-row stations due to inter-stage evaporation of water droplets introduced at the compressor inlet. The evaporation rate predicted by the model is compared with experimental data for stationary droplets in a duct. Performance predictions are compared with data for a GE-proprietary compressor. Study of various water droplet sizes and various water-to-air mass ratios is discussed.

Influence of Compressor Performance Maps Shape on Wet Compression

2008 ◽  
Author(s):  
Rakesh K. Bhargava ◽  
Michele Bianchi ◽  
Francesco Melino ◽  
Antonio Peretto ◽  
Pier Ruggero Spina
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Compression Process ◽  
Two Phase ◽  
Compressor Performance ◽  
Wet Compression ◽  
Calculation Code

In recent years, a great number of studies were carried out in order to analyze the main features of fogging technologies. The various fogging strategies seem to improve gas turbine and combined cycle power output with low initial investment cost and less installation downtime. In fact, nowadays fogging is successfully installed on several gasturbine and combined cycle power plants worldwide. In particular, overspray fogging and interstage injection involve two-phase flow consideration and water evaporation during compression process (also known as wet compression). The aim of the present paper is to further improve understanding of the wet compression process including stage-by-stage compressor behavior by investigating the influence of the axial compressor performance map shape on the evaporation process of the injected water through the compressor, achievable power boost, the maximum amount of water which can be injected and/or influence on the surge conditions. This analysis is carried out by using a calculation code, named IN.FO.G.T.E. (INterstage FOgging Gas Turbine Evaluation), developed and validated by the Authors.

Influence of Water Droplet Size and Temperature on Wet Compression

2007 ◽  
Author(s):  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
S. Ingistov
Keyword(s):  
Gas Turbine ◽  
Water Droplet ◽  
Droplet Diameter ◽  
Axial Compressor ◽  
Combined Cycle ◽  
Water Evaporation ◽  
Air Cooling ◽  
Compression Process ◽  
Two Phase ◽  
Wet Compression

In the last years, among all different gas turbine inlet air cooling techniques, an increasing attention to fogging approach is dedicated. The various fogging strategies seem to be a good solution to improve gas turbine or combined cycle produced power with low initial investment cost and less installation downtime. In particular, overspray fogging and interstage injection involve two-phase flow consideration and water evaporation during compression process (also known as wet compression). According to the Author’s knowledge, the field of wet compression is not completely studied and understood. In the present paper, all the principal aspects of wet compression and in particular the influence of injected water droplet diameter and surface temperature, and their effect on gas turbine performance and on the behavior of the axial compressor (change in axial compressor performance map due to the water injection, redistribution of stage load, etc.) are analyzed by using a calculation code, named IN.FO.G.T.E. (INterstage FOgging Gas Turbine Evaluation), developed and validated by the Authors.

Compressor Performance and Operability in Swirl Distortion

2010 ◽  
Author(s):  
Yogi Sheoran ◽  
Bruce Bouldin ◽  
P. Murali Krishnan
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Full Range ◽  
Axial Compressor ◽  
Cfd Model ◽  
Generator System ◽  
Sliding Mesh ◽  
Wide Range ◽  
Compressor Performance ◽  
The Impact

Inlet swirl distortion has become a major area of concern in the gas turbine engine community. Gas turbine engines are increasingly installed with more complicated and tortuous inlet systems, like those found on embedded installations on Unmanned Aerial Vehicles (UAVs). These inlet systems can produce complex swirl patterns in addition to total pressure distortion. The effect of swirl distortion on engine or compressor performance and operability must be evaluated. The gas turbine community is developing methodologies to measure and characterize swirl distortion. There is a strong need to develop a database containing the impact of a range of swirl distortion patterns on a compressor performance and operability. A recent paper presented by the authors described a versatile swirl distortion generator system that produced a wide range of swirl distortion patterns of a prescribed strength, including bulk swirl, twin swirl and offset swirl. The design of these swirl generators greatly improved the understanding of the formation of swirl. The next step of this process is to understand the effect of swirl on compressor performance. A previously published paper by the authors used parallel compressor analysis to map out different speed lines that resulted from different types of swirl distortion. For the study described in this paper, a computational fluid dynamics (CFD) model is used to couple upstream swirl generator geometry to a single stage of an axial compressor in order to generate a family of compressor speed lines. The complex geometry of the analyzed swirl generators requires that the full 360° compressor be included in the CFD model. A full compressor can be modeled several ways in a CFD analysis, including sliding mesh and frozen rotor techniques. For a single operating condition, a study was conducted using both of these techniques to determine the best method given the large size of the CFD model and the number of data points that needed to be run to generate speed lines. This study compared the CFD results for the undistorted compressor at 100% speed to comparable test data. Results of this study indicated that the frozen rotor approach provided just as accurate results as the sliding mesh but with a greatly reduced cycle time. Once the CFD approach was calibrated, the same techniques were used to determine compressor performance and operability when a full range of swirl distortion patterns were generated by upstream swirl generators. The compressor speed line shift due to co-rotating and counter-rotating bulk swirl resulted in a predictable performance and operability shift. Of particular importance is the compressor performance and operability resulting from an exposure to a set of paired swirl distortions. The CFD generated speed lines follow similar trends to those produced by parallel compressor analysis.

scholarly journals Effects of Stator Indexing on Performance in a Low Speed Multistage Axial Compressor

1997 ◽  
Author(s):  
Wendy S. Barankiewicz ◽  
Michael D. Hathaway
Keyword(s):  
Peak Pressure ◽  
Axial Compressor ◽  
Loss Coefficient ◽  
Operating Conditions ◽  
Nasa Lewis Research ◽  
Performance Measurements ◽  
Peak Efficiency ◽  
Blade Row ◽  
The Impact ◽  
Multistage Axial Compressor

The results of an experimental investigation to determine the impact of stator row indexing or clocking on multistage axial compressor performance are presented. Testing was conducted in the NASA Lewis Research Center’s Four-Stage Axial Compressor Facility. The impact of stator row indexing on both the overall and stator 3 blade element performance is presented for both the peak efficiency and peak pressure operating conditions. The change in overall performance due to stator indexing is 0.2% for both operating conditions. Indexing resulted in a 5% change in stator 3 mass averaged loss coefficient at the peak efficiency condition and a 10% change at the peak pressure condition. Since the mass-averaged stator 3 loss coefficient is on the order of 7%, the changes in loss coefficient due to indexing are on the order of 0.35–0.7%. These changes are considered to be small and are of the same order of magnitude as the passage-to-passage differences in loss coefficient due to manufacturing and assembly tolerances in the test compressor. The effects of stator-stator wake interactions are also shown and indicate that for rows with unequal blade counts it may be necessary to survey across more than one blade row pitch for accurate blade row performance measurements.

Compressor Performance and Operability in Swirl Distortion

2011 ◽  
Vol 134 (4) ◽  
Author(s):  
Yogi Sheoran ◽  
Bruce Bouldin ◽  
P. Murali Krishnan
Keyword(s):  
Gas Turbine ◽  
Complex Geometry ◽  
Full Range ◽  
Axial Compressor ◽  
Cfd Model ◽  
Generator System ◽  
Sliding Mesh ◽  
Wide Range ◽  
Compressor Performance ◽  
The Impact

Inlet swirl distortion has become a major area of concern in the gas turbine engine community. Gas turbine engines are increasingly installed with more complicated and tortuous inlet systems such as those found on embedded installations on unmanned aerial vehicles. These inlet systems can produce complex swirl patterns in addition to total pressure distortion. The effect of swirl distortion on engine or compressor performance and operability must be evaluated. The gas turbine community is developing methodologies to measure and characterize swirl distortion. There is a strong need to develop a database containing the impact of a range of swirl distortion patterns on a compressor performance and operability. A recent paper presented by the authors described a versatile swirl distortion generator system that produced a wide range of swirl distortion patterns of a prescribed strength, including bulk swirl, twin swirl, and offset swirl. The design of these swirl generators greatly improved the understanding of the formation of swirl. The next step of this process is to understand the effect of swirl on compressor performance. A previously published paper by the authors used parallel compressor analysis to map out different speed lines that resulted from different types of swirl distortion. For the study described in this paper, a computational fluid dynamics (CFD) model is used to couple upstream swirl generator geometry to a single stage of an axial compressor in order to generate a family of compressor speed lines. The complex geometry of the analyzed swirl generators requires that the full 360 deg compressor be included in the CFD model. A full compressor can be modeled several ways in a CFD analysis, including sliding mesh and frozen rotor techniques. For a single operating condition, a study was conducted using both of these techniques to determine the best method, given the large size of the CFD model and the number of data points that needed to be run to generate speed lines. This study compared the CFD results for the undistorted compressor at 100% speed to comparable test data. Results of this study indicated that the frozen rotor approach provided just as accurate results as the sliding mesh but with a greatly reduced cycle time. Once the CFD approach was calibrated, the same techniques were used to determine compressor performance and operability when a full range of swirl distortion patterns were generated by upstream swirl generators. The compressor speed line shift due to co-rotating and counter-rotating bulk swirl resulted in a predictable performance and operability shift. Of particular importance is the compressor performance and operability resulting from an exposure to a set of paired swirl distortions. The CFD generated speed lines follow similar trends to those produced by parallel compressor analysis.

Experimental Determination of a Four Stage Axial Compressor Map Operating in Wet Compression

2014 ◽  
Author(s):  
J. P. Schnitzler ◽  
I. von Deschwanden ◽  
S. Clauss ◽  
F. K. Benra ◽  
H. J. Dohmen ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Flow Behavior ◽  
Water Injection ◽  
Axial Compressor ◽  
Evaporation Process ◽  
Water Droplets ◽  
Test Rig ◽  
Measurement Results ◽  
Wet Compression ◽  
The Impact

Injecting water in the air upstream of an axial compressor intake is an effective method to increase the efficiency and the power output of a gas turbine application especially at hot days. Reasoned by their complex two phase flow axial compressors which operate in wet compression mode are in the focus of present thermodynamic analysis, numerical investigations and experimental research. Recently the evaporation process of water droplets, especially at high temperature and pressure levels has been investigated with the laser based measurement technique Phase Doppler Particle Analyzer (PDPA) in detail in a stationary test rig at the University of Duisburg-Essen. The focus of these investigations has been laid on the analysis of the evaporation process in a free stream or cross flow behavior without droplet wall interaction. In this paper the first results of the novel four stage axial compressor test rig are published. This test rig is arranged for high amount of water injection with special optical access for laser based measurements. The first part of the paper outlines the general design, geometric facts and aerodynamic reference parameters of the test rig and gives an introduction to the installed conventional measurement technique. Discrete measurement results from dry runs are compared with CFD results to validate the gathered experimental data. In the second part of the paper the previously discussed dry runs are compared with measurement results of runs with water injection. The amount of water to air ratio is varied and the effects on the operating behavior of the four stage axial compressor are pointed out in detail. Furthermore results from the laser based PDPA measurements at the inlet and at the outlet of the compressor outline the impact on the water droplets moving through the compressor in wet compression mode.

Implementation of Microchannel Evaporator for High-Heat-Flux Refrigeration Cooling Applications

2005 ◽  
Vol 128 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Jaeseon Lee ◽  
Issam Mudawar
Keyword(s):  
Heat Sink ◽  
High Heat ◽  
High Heat Flux ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Small Width ◽  
Compressor Inlet ◽  
Compressor Performance ◽  
Wet Compression ◽  
Cycle Efficiency

While most recently electronic cooling studies have been focused on removing the heat from high-power-density devices, the present study also explores means of greatly decreasing the device operating temperature. This is achieved by incorporating a microchannel heat sink as an evaporator in an R134a refrigeration loop. This system is capable of maintaining device temperatures below 55°C while dissipating in excess of 100W∕cm2. It is shown that while higher heat transfer coefficients are possible with greater mass velocities, those conditions are typically associated with wet compression corresponding to evaporator exit quality below unity and liquid entrainment at the compressor inlet. Wet compression compromises compressor performance and reliability as well as refrigeration cycle efficiency and therefore must be minimized by maintaining only slightly superheated conditions at the compressor inlet, or using a wet-compression-tolerant compressor. A parametric study of the effects of channel geometry on heat sink performance points to channels with small width and high aspect ratio as yielding superior thermal performance corresponding to only a modest penalty in pressure drop.

An Evaluation of the Effects of Water Injection on Compressor Performance

2003 ◽  
Author(s):  
A. J. White ◽  
A. J. Meacock
Keyword(s):  
Gas Turbines ◽  
Evaporative Cooling ◽  
Water Injection ◽  
Compression Process ◽  
Compressor Inlet ◽  
Design Behaviour ◽  
Industrial Gas Turbines ◽  
Compressor Performance ◽  
Compressor Work ◽  
The Impact

The injection of water droplets into compressor inlet ducting is now commonly used as a means of boosting the output from industrial gas turbines. The chief mechanisms responsible for the increase in power are the reduction in compressor work per unit flow and the increase in mass flow rate, both of which are achieved by evaporative cooling upstream of and within the compressor. This paper examines the impact of such evaporative processes on compressor operation, focussing particular attention on cases with substantial over-spray — i.e., for which significant evaporation takes place within the compressor itself, rather than in the inlet. A simple numerical method is described for the computation of wet compression processes, based on a combination of droplet evaporation and mean-line calculations. The method is applied to a “generic” compressor geometry in order to investigate the nature of the off-design behaviour that results from evaporative cooling. Consideration is also given to the efficiency of the compression process, the implications for choking and stall, and the magnitude of the thermodynamic loss resulting from irreversible phase change.

Experimental Investigation of the Aerodynamic Performance of a Linear Axial Compressor Cascade With Water Droplet Loading

2010 ◽  
Author(s):  
Tjark Eisfeld ◽  
Franz Joos
Keyword(s):  
Water Injection ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Two Dimensional ◽  
Compressor Cascade ◽  
Compressor Rotor ◽  
Two Dimensional Flow ◽  
Wet Compression ◽  
The Impact

Wet compression operation is a commercially attractive way to increase power output and efficiency of a gas turbine cycle. In recent literature the impact of water loading on the aerodynamic performance of the blading has not been entirely clarified yet. The most significant issues of aerodynamics in wet compression are stage rematching and stability. Therefore, these subjects are investigated in a linear compressor rotor cascade. This setup allows an estimation of the aerodynamic performance of the blading from two-dimensional test data at various operating conditions. Moreover, the impact of droplet flow on the two-dimensional flow field of the blade passage is measured in detail in order to understand the deviation of performance parameters. The results indicate that the effect of water injection on compressor aerodynamics is strongly related to the operating condition. It appears that droplet loading has a beneficial effect on the flow at high blade loading.

Reconciling Compressor Performance Differences for Varying Ambient Inlet Conditions

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Natalie R. Smith ◽  
Reid A. Berdanier ◽  
John C. Fabian ◽  
Nicole L. Key
Keyword(s):  
Pressure Ratio ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Ambient Conditions ◽  
Thermal Growth ◽  
Reynolds Number Effects ◽  
Compressor Inlet ◽  
Compressor Performance ◽  
Inlet Conditions ◽  
Research Facilities

Careful experimental measurements can capture small changes in compressor total pressure ratio (TPR), which arise with subtle changes in an experiment's configuration. Research facilities that use unconditioned atmospheric air must account for changes in ambient compressor inlet conditions to establish repeatable performance maps. A unique dataset from a three-stage axial compressor has been acquired over the duration of 12 months in the Midwest U.S., where ambient conditions change significantly. The trends show a difference in compressor TPR measured on a cold day versus a warm day despite correcting inlet conditions to sea level standard day. To reconcile these differences, this paper explores correcting the compressor exit thermodynamic state, Reynolds number effects, and variations in rotor tip clearance (TC) as a result of differences in thermal growth.

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