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.

Investigation of Water Film Formation on Blade Surfaces of a Wet Compression Transonic Compressor Rotor

2015 ◽  
Author(s):  
Hai Zhang ◽  
Bin Jiang ◽  
Mingcong Luo ◽  
Xiangkun Liu ◽  
Shuangming Fan ◽  
...  
Keyword(s):  
Film Formation ◽  
Water Injection ◽  
Water Film ◽  
Inertia Force ◽  
Blade Surface ◽  
Water Droplets ◽  
Suction Surface ◽  
Transonic Compressor ◽  
Pressure Surface ◽  
Wet Compression

As is known, when water injected at the inlet of the compressor, the water droplets will move onto the blade where water film could form on the blade surface. In this paper, the movement and formation of the water film on a transonic rotor, NASA Rotor 37, are simulated and analyzed by using unsteady numerical methods under different water injecting conditions. The motions of water droplets and flows in the blade passage are presented in detail. Tearing process of water film on the blade surface is also a key point of this research. The preliminary results indicate that the movement of water droplets is tending to deviate from the suction surface and pile on the pressure surface due to the effect of inertia force, and water film could be formed on the pressure surface. Continuity and scope of the water film on the blade surface will develop with the increasing of droplet sizes and water injection rate. Based on the simulation, it is found that more discrete water films are formed on the pressure side of blade when the droplets move onto the pressure surface, tearing phenomenon may occur where the area is of lower water film thickness. Smaller enough sprayed droplet size can not only ensure the compressor performance of wet compression, but also avoid the erosion caused by water film accumulation.

Refinement of Water Droplets With Surfactants for Wet Compression of Gas Turbine

2009 ◽  
Author(s):  
Rongkai Zhu ◽  
Qun Zheng ◽  
Guoqiang Yue ◽  
Rakesh Bhargava
Keyword(s):  
Surface Tension ◽  
Gas Turbine ◽  
Experimental Work ◽  
Ionic Surfactants ◽  
Water Droplets ◽  
Compression Process ◽  
Surface Behavior ◽  
Wet Compression ◽  
The Cost

Concerned with the influence of the size of water droplets on the effect of wet compression, it is important to control the size of water droplets among 5–10 microns or smaller, for this purpose an experimental work is carried out by improve the surface behavior of water aiming to reduce its surface tension. Non-ionic surfactants and its combination were employed to reach such an aim. The surface tension of water was reduced from 72.9mN/m to 41.2mN/m or even lower depending on the cost. It offers a possible way to refine spray, and ready to use in wet compression process.

Flow Assessment on the Effects of Water Droplets on Rotor Region of Wet Compression

2017 ◽  
Vol 374 ◽  
pp. 131-147
Author(s):  
Gambo Kofar Bai Dayyabu ◽  
Hai Zhang ◽  
Qun Zheng ◽  
Salman Abdu
Keyword(s):  
Gas Turbine ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Water Droplets ◽  
Compression Process ◽  
Transonic Compressor ◽  
Depth Analysis ◽  
Wet Compression

Wet compression process has been widely accepted as a measure of increasing the performance of industrial gas turbine, in the present work, in-depth analysis on the principle aspects of wet compression, more specifically, the influence of injected water droplets diameter, surface temperature, and their effects on the behavior of axial flow transonic compressor and gas turbine performance were analyzed using computational fluid dynamic. Injected water droplets and gas flow phase change was most intense in the area adjacent to shockwaves and were the slip velocity of the droplet is highest. Water injection in to the compressor rotor is a little perturbation to the flow field due to the formation of flow separation, evaporation rate, increasing weber number, reduction in the inlet temperature, and velocity vortex pattern relatively different from that of the dry case. The effects of water droplets on the rotor region at injection rate of 1%, shows decrease in the inlet temperature of 11%, outlet temperature 5% and uplift the efficiency to 1.5%.

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.

Thermodynamic Analyses of Wet Compression Process in the Compressor of Gas Turbine

2002 ◽  
Author(s):  
Qun Zheng ◽  
Yufeng Sun ◽  
Shuying Li ◽  
Yunhui Wang
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Model ◽  
Water Droplet ◽  
Evaporative Cooling ◽  
Process Water ◽  
Water Droplets ◽  
Compression Process ◽  
Compression Efficiency ◽  
Wet Compression

Thermodynamic model of wet compression process is established in this paper. The topics of ideal wet compression process, actual wet compression process, water droplet evaporative rate, wet compression work, inlet evaporative cooling, concept of wet compression efficiency, aerodynamic breaking of water droplets etc. are investigated and discussed in this 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.

Thermodynamic Analyses of Wet Compression Process in the Compressor of Gas Turbine

2003 ◽  
Vol 125 (3) ◽  
pp. 489-496 ◽  
Author(s):  
Qun Zheng ◽  
Yufeng Sun ◽  
Shuying Li ◽  
Yunhui Wang
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Model ◽  
Water Droplet ◽  
Evaporative Cooling ◽  
Process Water ◽  
Water Droplets ◽  
Compression Process ◽  
Compression Efficiency ◽  
Wet Compression

Thermodynamic model of wet compression process is established in this paper. The topics of ideal wet compression process, actual wet compression process, water droplet evaporative rate, wet compression work, inlet evaporative cooling, concept of wet compression efficiency, aerodynamic breaking of water droplets etc. are investigated and discussed in this paper.

Effects of Inlet Fogging and Wet Compression on Gas Turbine Performance

2006 ◽  
Author(s):  
Sepehr Sanaye ◽  
Hossein Rezazadeh ◽  
Mehrdad Aghazeynali ◽  
Mehrdad Samadi ◽  
Daryoush Mehranian ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Water Droplets ◽  
Turbine Performance ◽  
Compressor Inlet ◽  
Wet Compression ◽  
Inlet Duct

Inlet fogging has been noticed widely in recent years as a method of gas turbine air inlet cooling for increasing the power output of gas turbines and combined cycle power plants. To study the effects of inlet fogging on gas turbine performance, in the first step, the evaporation of water droplets in the compressor inlet duct was modeled, and at the end of the inlet duct, the diameter of water droplets were estimated. The results of this process were compared with the results of FLUENT software. In the second step, the droplets which were not evaporated in compressor inlet duct were studied during wet compression in the compressor and the reduction in compressor discharge air temperature was predicted. Finally, the effects of both evaporative cooling in inlet duct, and wet compression in compressor, on the power output, and turbine exhaust temperature of a gas turbine with turbine blade cooling were investigated. These results for various amounts of air bleeding, without and with inlet fogging in the range of (0–2%) overspray are reported.

Water Film Formation and Performance Effect on Compressor Stage in Water Injection Process

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Chunlei Liu ◽  
Hai Zhang ◽  
Lu Yang ◽  
Qun Zheng ◽  
Guoqiang Yue
Keyword(s):  
Film Formation ◽  
Water Injection ◽  
Water Film ◽  
Injection Rate ◽  
Compressor Stage ◽  
Blade Surface ◽  
Performance Effect ◽  
Injection Process ◽  
Flow Mechanisms ◽  
And Performance

AbstractIn this study, the thickness of water film, which is frequently formed on compressor blade surface, was investigated. Simultaneously, its movement and extra torque demand were provided by a simulation model of the code. Having taken into account the transformation in blade’s profile and the thickness feature of the films, the working medium characteristic transformation in compressor stage was analyzed. In addition, formation, development and movement of the water film on a compressor stage were simulated by using unsteady numerical methods in various water injected conditions. Movement characteristics of water droplets in cascade were investigated to understand the flow mechanisms responsible for water film formation process. The forming and the tearing process of water films, which formed on the blade surface, were analyzed at different injection conditions. In consideration of the “Scoop effect” in actual situation, the maximum quantity of injected water can reach 12 %. Results indicated that continuity and region of the film would be developed with the increment of droplet size and injection rate. It was also found that water film’s tearing process brought about flow losses near blade surface due to the increment of surface roughness.

Heat and Mass Transfer Characteristics of Water Droplets in Wet Compression Process

2017 ◽  
Author(s):  
Chunlei Liu ◽  
Xiang Li ◽  
Hai Zhang ◽  
Qun Zheng
Keyword(s):  
Fluid Dynamics ◽  
Mass Transfer ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Heat And Mass Transfer ◽  
Rotor Blades ◽  
Compressor Stage ◽  
Water Droplets ◽  
Motion Parameters ◽  
Wet Compression

Wet compression technology is an economic and effective approach to improve the performance of gas turbine. In the process of wet compression, the gas turbine engine will ingest a certain amount of water, which can influence the overall performance of the engine. Thermodynamic process and performance of compressor are influenced significantly by heat and mass transfer of the injected water droplets. This study is a new research of investigating theoretically the water droplets effects on the heat and mass transfer characteristics. It focuses on the aerodynamic and thermodynamic effects of the two-phase flow in the compressor stage. The application of Computational Fluid Dynamics (CFD) is the basic method to examine the details of the flow in an axial compressor stage and how it is affected by the presence of water, especially by the water droplets. The computation of water droplets characteristics, are provided by a simulation model of the code named CFX. Considering the change in aerodynamics and thermodynamics feature due to the water droplets, the compressor stage’s performance variations are analyzed. The movement and the evaporation of the water droplets in 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 wet compression formation process. The investigation of water droplets in compression can help to understand some phenomenons by using wet compression technology. The flow of water droplets between rotor blades are analyzed by using computational fluid dynamics method. Full coupling between gas and water droplets are adopted, allowing gas and water droplets to affect each other. Many motion parameters of water droplets are researched, such as slip velocity, Weber number and Reynolds number. The forces acting on water droplet are also discussed. Aerodynamic breakup of water droplets and interactions between water droplets and wall are taken into consideration at the same time. The results indicate that: (1) The motion of water droplets in compression areor mainly controlled by drag force. The motion parameters of water droplets changes mostly at the entrance of flow passage between rotor blades, and the turbulence intensity and breakup strength of water droplets reaches their maximum at the entrance. (2) The flow angle of water droplets is bigger than gas in rotor region due to their inertia, which can explain why water droplets have bigger separation degree and are easier to flow toward blade pressure surface. (3) The motion of water droplets in stator region is also important to be investigated for wet compression, and the motion analysis of single water droplets between blades is still needed to be developed, so more investigation will be carried out.

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