Application of a Computational Code to Simulate Interstage Injection Effects on GE Frame 7EA Gas Turbine

2006 ◽  
Author(s):  
M. Bagnoli ◽  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Modeling ◽  
Water Injection ◽  
Compressor Stage ◽  
Performance Parameters ◽  
Turbine Performance ◽  
Computational Code ◽  
Compressor Performance ◽  
Fortran 90 ◽  
Injection Location

This paper investigates effects of interstage water injection on the performance of a GE Frame 7EA gas turbine using aero-thermodynamic modeling. To accomplish this objective a computational code, written in Fortran 90 language and developed by DIEM – University of Bologna, has been used. The calculation procedure considers effects of evaporation of injected water within the compressor including droplets dynamics which are necessary in order to fully evaluate effects of wet compression on the gas turbine performance. The robustness of the computational code is demonstrated by evaluating stage-by-stage compressor performance and the overall gas turbine performance in presence of inlet evaporative fogging, overspray fogging and interstage water injection. The presented results show that water injection location influences compressor stage loading redistribution differently. The plausible explanations to the observed trends of various performance parameters are presented in the paper.

Application of a Computational Code to Simulate Interstage Injection Effects on GE Frame 7EA Gas Turbine

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
M. Bagnoli ◽  
M. Bianchi ◽  
F. Melino ◽  
A. Peretto ◽  
P. R. Spina ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Water Injection ◽  
Calculation Procedure ◽  
Compressor Stage ◽  
Performance Parameters ◽  
Turbine Performance ◽  
Computational Code ◽  
Compressor Performance ◽  
Fortran 90 ◽  
Injection Location

This paper investigates effects of interstage water injection on the performance of a GE Frame 7EA gas turbine using aerothermodynamic modeling. To accomplish this objective, a computational code, written in FORTRAN 90 language and developed by DIEM University of Bologna, has been used. The calculation procedure considers effects of evaporation of injected water within the compressor including droplets dynamics, which are necessary in order to fully evaluate effects of wet compression on the gas turbine performance. The robustness of the computational code is demonstrated by evaluating stage-by-stage compressor performance and the overall gas turbine performance in the presence of inlet evaporative fogging, overspray fogging, and interstage water injection. The presented results show that water injection location influences compressor stage loading redistribution differently. The plausible explanations to the observed trends of various performance parameters are presented in this paper.

Formation Process of Water Film and Performance Effect on Compressor Stage

2016 ◽  
Author(s):  
Hai Zhang ◽  
Xiaojiang Tian ◽  
Xiaojun Pan ◽  
Jie Zhou ◽  
Qun Zheng
Keyword(s):  
Gas Turbine ◽  
Formation Process ◽  
Water Injection ◽  
Water Film ◽  
Compressor Stage ◽  
Blade Surface ◽  
Water Droplets ◽  
Compression Process ◽  
Turbine Performance ◽  
Wet Compression

In process of wet compression, gas turbine engine will ingest a certain amount of water, which can influence the overall performance of the engine. This phenomenon is particularly significant in the cleaning process of industrial gas turbine and water injection of aero-engine. When the quantity of water ingestion is quite large, the performance of gas turbine will appear deterioration and may lead to flameout, power reduce or even shutdown of the engine, causing accidents. Water droplets will be accumulated on the blade surface where water films could be formed on pressure surface in the wet compression process. The effects of water film on gas turbine engines are aerodynamic, thermodynamic and mechanical. The above-mentioned effects occur simultaneously and be affected by each other. Considering the above effects and the fact that they are time dependent, there are few gas turbine performance researches, which take into account the water film phenomenon. This study is a new research of investigating theoretically the water film effects on a gas turbine performance. It focuses on the aerodynamic and thermodynamic effects of the phenomenon on the compressor stage. The computation of water film thickness, which frequently be formed on the surface of compressor blade, its movement and extra torque demand, are provided by a simulation model of the code. Considering the change in blade’s profile and the thickness feature of the water film, the compressor stage’s performance deterioration is analyzed. In addition to this, movement and the formation of the water film on a compressor stage are simulated and analyzed by using unsteady numerical methods under different water injecting conditions in this paper. The movement characteristics of water droplets in compressor passage are investigated to understand the flow mechanisms responsible for water film formation process. The forming and the tearing process of water film on blade surface are analyzed at different injection conditions. For simulating the real situation, The maximum quantity of injected water can reach 12%. The results indicate that continuity and region of the water film on the blade surface will be developed with the increment of droplet size and injection rate. It is also found that the flow losses near blade surface increases with the tearing process of water film due to the increment of surface roughness.

Numerical Analysis of the Effects of Non-Uniform Surface Roughness on Compressor Stage Performance

2010 ◽  
Author(s):  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Mauro Venturini
Keyword(s):  
Surface Roughness ◽  
Gas Turbine ◽  
Traditional Approach ◽  
Fluid Dynamic ◽  
Turbine Blades ◽  
Compressor Stage ◽  
Turbine Performance ◽  
Performance Map ◽  
Overall Performance ◽  
Stage Performance

Gas turbine performance degradation over time is mainly due to the deterioration of compressor and turbine blades, which, in turn, causes a modification of the compressor and turbine performance maps. Since detailed information about the actual modification of the compressor and turbine performance maps is usually unavailable, component performance can be modeled and investigated (i) by scaling the overall performance map, or (ii) by using stage-by-stage models of the compressor and turbine and by scaling each single stage performance map to account for each stage deterioration, or (iii) by performing 3D numerical simulations, which allow to both highlight the fluid-dynamic phenomena occurring in the faulty component and grasp the effect on the overall performance of the component. In this paper, the authors address the most common and experienced source of loss for a gas turbine, i.e. compressor fouling. With respect to the traditional approach, which mainly aims at the identification of the overall effects of fouling, authors investigate a micro-scale representation of compressor fouling (e.g. blade surface deterioration and flow deviation). This allows (i) a more detailed investigation of the fouling effects (e.g. mechanism, location along blade height, etc.), (ii) a more extensive analysis of the causes of performance deterioration and (iii) the assessment of the effect of fouling on stage performance coefficients and on stage performance maps. The effects of a non-uniform surface roughness on both rotor and stator blades of an axial compressor stage are investigated by using a commercial CFD code. The NASA Stage 37 test case was used as the baseline geometry. The numerical model already validated against experimental data available in literature was used for the simulations. Different non-uniform combinations of surface roughness levels on rotor and stator blades were imposed. This makes it possible to highlight how the localization of fouling on compressor blades affects compressor performance, both at an overall and at a fluid-dynamic level.

Analysis of the Effects of Water Injection on the Performance of a Gas Turbine

2002 ◽  
Vol 124 (3) ◽  
pp. 489-495 ◽  
Author(s):  
K. Mathioudakis
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Test Data ◽  
Main Parameter ◽  
Water Injection ◽  
Performance Testing ◽  
Performance Parameters ◽  
Order Of Magnitude ◽  
Industrial Gas Turbine ◽  
Account Variation

The effect of water injection in the combustion chamber of an industrial gas turbine is studied by means of analytic relations. Equations for the estimation of changes in the main performance parameters are provided. The relations are derived on the basis of an order of magnitude analysis and taking into account variation of gas properties due to water injection as well as changes in the interrelation of component performance parameters. It is shown that water/fuel ratio is the main parameter on which performance deviations depend. Data from the performance testing of an industrial gas turbine are used to check the validity of the proposed relations. The comparison of the predictions to the test data shows that the mechanisms of performance deviations are well modeled by the analysis presented.

Study of KJ-66 micro gas turbine compressor: Steady and unsteady Reynolds-averaged Navier–Stokes approach

2016 ◽  
Vol 231 (5) ◽  
pp. 904-917 ◽  
Author(s):  
Junting Xiang ◽  
Jörg Uwe Schlüter ◽  
Fei Duan
Keyword(s):  
Gas Turbine ◽  
Transient Flow ◽  
Numerical Study ◽  
Navier Stokes ◽  
Compressor Stage ◽  
Micro Gas Turbine ◽  
Operation Speed ◽  
Compressor Performance ◽  
Reynolds Averaged Navier Stokes ◽  
Gas Turbine Compressor

Numerical study on the compressor stage of a KJ-66 micro gas turbine was conducted in this paper through both steady and unsteady Reynolds-averaged Navier–Stokes. The study was conducted for the numerical prediction of micro gas turbine compressor performance at various operation conditions, with special attention given to the transient flow behaviors during compressor operation. The numerical results showed reasonable agreements with experimental data while providing predictions for the charting of compressor performance map at various operation speeds. The simulation results indicated that the increase of operation speed from 80 k r/min to 117 k r/min would leads to an increased peak total pressure ratio from 1.54 to 1.96, while decreasing the peak adiabatic efficiency from 0.73 to 0.55. This paper also provided discussion on details of transient flow field within the compressor stage as well as demonstrated the smooth flow transition through rotor–stator interactions.

Compressor Fouling Modeling: Relationship Between Computational Roughness and Gas Turbine Operation Time

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Francesco Melino ◽  
Mirko Morini ◽  
Antonio Peretto ◽  
Michele Pinelli ◽  
Pier Ruggero Spina
Keyword(s):  
Fluid Dynamics ◽  
Surface Roughness ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Axial Compressor ◽  
Operation Time ◽  
Compressor Stage ◽  
Performance Map ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance

Gas turbine axial compressor performance is heavily influenced by blade fouling. As a result, the gas turbines efficiency and producible power output decrease. Performance degradation of an axial compressor stage due to fouling can be analyzed by means of simulation through computational fluid dynamics (CFD) codes. Usually these methods reproduce the deteriorated blades by increasing their surface roughness and thickness. Another approach is the scaling of compressor stage performance maps. A model based on stage-by-stage techniques was presented in a previous work. This model is able to estimate the modifications of the overall compressor performance map as a function of the operating hours. The aim of the present study is to combine these two different approaches in order to relate the increase of blade computational surface roughness with compressor operating hours.

Compressor Fouling Modeling: Relationship Between Computational Roughness and Gas Turbine Operation Time

2011 ◽  
Author(s):  
Francesco Melino ◽  
Mirko Morini ◽  
Antonio Peretto ◽  
Michele Pinelli ◽  
Pier Ruggero Spina
Keyword(s):  
Fluid Dynamics ◽  
Surface Roughness ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Axial Compressor ◽  
Operation Time ◽  
Compressor Stage ◽  
Performance Map ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance

Gas turbine axial compressor performance is heavily influenced by blade fouling; as a result, the gas turbines efficiency and producible power output decrease. Performance degradation of an axial compressor stage due to fouling can be analyzed by means of simulation through Computational Fluid Dynamics (CFD) codes. Usually these methods reproduce the deteriorated blades by increasing their surface roughness and/or thickness [1]. Another approach is the scaling of compressor stage performance maps. A model based on stage-by-stage techniques was presented in a previous work. This model is able to estimate the modifications of the overall compressor performance map as a function of the operating hours [2]. The aim of the present study is to combine these two different approaches in order to relate the increase of blade computational surface roughness with compressor operating hours.

Compressor Performance With Water Injection

2001 ◽  
Author(s):  
J. H. Horlock
Keyword(s):  
Specific Heat ◽  
Gas Turbine ◽  
Dimensional Analysis ◽  
Water Injection ◽  
Operating Conditions ◽  
Water Droplets ◽  
One Dimensional ◽  
Design Performance ◽  
Effective Specific Heat ◽  
Compressor Performance

There has been renewed interest recently in the injection of water at inlet to gas turbine plants. As is to be expected there is a drop in temperature at the inlet face to the compressor and this obviously has an effect on compressor performance. But a second effect occurs within the early stages of the compressor itself, associated with an increase in the effective specific heat due to continuing evaporation of the water droplets. Consequently there are movements away from design operating conditions on the stage characteristics. A one-dimensional analysis of compressor off-design performance is developed to illustrate these effects, which appear to be appreciable, even for very small quantities of water injection.

Numerical Analysis of the Effects of Nonuniform Surface Roughness on Compressor Stage Performance

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Mauro Venturini
Keyword(s):  
Surface Roughness ◽  
Gas Turbine ◽  
Fluid Dynamic ◽  
Turbine Blades ◽  
Compressor Stage ◽  
Nonuniform Surface ◽  
Turbine Performance ◽  
Performance Map ◽  
Overall Performance ◽  
Stage Performance

Gas turbine performance degradation over time is mainly due to the deterioration of compressor and turbine blades, which, in turn, causes a modification of the compressor and turbine performance maps. Since the detailed information about the actual modification of the compressor and turbine performance maps is usually unavailable, the component performance can be modeled and investigated by the following: scaling the overall performance map, using stage-by-stage models of the compressor and turbine, and scaling each single stage performance map to account for each stage deterioration, or performing 3D numerical simulations, which allow to both highlight the fluid-dynamic phenomena occurring in the faulty component and grasp the effect on the overall performance of each affected component. In this paper, the authors address the most common and experienced source of loss for a gas turbine, i.e., compressor fouling. With respect to the traditional approach, which mainly aims at the identification of the overall effects of fouling, authors investigate a microscale representation of compressor fouling (i.e., blade surface deterioration and flow deviation). This allows (i) a more detailed investigation of the fouling effects (e.g., mechanism, location along blade height, etc.), (ii) a more extensive analysis of the causes of performance deterioration, and (iii) the assessment of the effect of fouling on stage performance coefficients and on stage performance maps. In this paper, the effect of nonuniform surface roughness on both rotor and stator blades of an axial compressor stage is investigated by using a commercial CFD code. The NASA Stage 37 test case is considered as the baseline geometry and a numerical model already validated against experimental data available in literature is used for the simulations. Different nonuniform combinations of surface roughness levels are imposed on rotor and stator blades. This makes it possible to highlight how the localization of fouling on compressor blades affects compressor performance both at an overall and at a fluid-dynamic level.

Gas Turbine Performance Prediction by Using Generalized Performance Curves of Compressor and Turbine Stages

2002 ◽  
Author(s):  
P. R. Spina
Keyword(s):  
Gas Turbine ◽  
Performance Prediction ◽  
Pressure Coefficient ◽  
Flow Coefficient ◽  
Unknown Parameters ◽  
Turbine Performance ◽  
Performance Curves ◽  
Multistage Turbine ◽  
Compressor Performance ◽  
Stage Performance

The paper presents a method for gas turbine performance prediction which uses compressor and turbine performance maps obtained by using generalized stage performance curves matched by means of the “stage–stacking” procedure. In particular, the overall multistage compressor performance is predicted using generalized relationships between stage efficiency, pressure coefficient and flow coefficient, while the multistage turbine performance is predicted by modeling each turbine stage by a series of two nozzles, a fixed one (stator) and a moving one (rotor). The characteristic of the proposed method is that the unknown parameters defining the generalized stage performance curves are determined by combining a Cycle Program with the compressor and turbine performance maps obtained using the “stage–stacking” procedure, and by searching for the values of the unknown parameters which better reproduce, by means of the Cycle Program, the overall performance and thermodynamic data measured on a gas turbine.

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