scholarly journals Discussion of Some Myths/Features Associated With Gas Turbine Inlet Fogging and Wet Compression

2012 ◽  
Author(s):  
Ting Wang ◽  
Jobaidur R. Khan
Keyword(s):  
Entropy Production ◽  
Gas Turbine ◽  
Power Output ◽  
Effective Means ◽  
Total Power ◽  
Water Evaporation ◽  
Water Droplets ◽  
Turbine Inlet ◽  
Wet Compression ◽  
Total Power Output

Gas turbine inlet fogging and overspray (high-fogging) have been considered the most cost-effective means of boosting a gas turbine’s total power output, especially under hot or dry weather conditions. The result of employing fogging or overspray is indisputably clear — total power output is increased; however, development of the theory and explanation of the phenomena associated with fogging and overspray are not always consistent and are sometimes misleading and incorrect. This paper focuses on reviewing several interesting features and commonly discussed topics, including (a) entropy production of water evaporation, (b) the effect of centrifugal force on water droplets, and (c) whether water droplets can survive the journey in the compressor and enter the combustor. Furthermore, three turbine myths: that fogging/overspray increases the air density in the compressor, reduces the compressor power consumption, and noticeably enhances the gas turbine efficiency, are examined and discussed. Some common mistakes in describing the compressor work are identified and corrected. A newly constructed multiphase T-S diagram is used to explain the physics of water droplet evaporation process and corresponding entropy production during wet compression.

scholarly journals Discussion of Some Myths/Features Associated With Gas Turbine Inlet Fogging and Wet Compression

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Ting Wang ◽  
Jobaidur R. Khan
Keyword(s):  
Entropy Production ◽  
Gas Turbine ◽  
Power Output ◽  
Effective Means ◽  
Weather Conditions ◽  
Total Power ◽  
Water Evaporation ◽  
Water Droplets ◽  
Wet Compression ◽  
Total Power Output

Gas turbine (GT) inlet fogging and overspray (high-fogging) have been considered the most cost-effective means of boosting a GT's total power output, especially under hot or dry weather conditions. The result of employing fogging or overspray is indisputably clear—total power output is increased; however, development of the theory and explanation of the phenomena associated with fogging and overspray are not always consistent and are sometimes misleading and incorrect. This paper focuses on reviewing several interesting features and commonly discussed topics, including (a) entropy production of water evaporation, (b) the effect of centrifugal force on water droplets, and (c) whether water droplets can survive the journey in the compressor and enter the combustor. Furthermore, three turbine myths that fogging/overspray increases the air density in the compressor, reduces the compressor power consumption, and noticeably enhances the GT efficiency are examined and discussed. Some common mistakes in describing the compressor work are identified and corrected. A newly constructed multiphase T–s diagram is used to explain the physics of water droplet evaporation process and corresponding entropy production during wet compression.

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.

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.

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.

scholarly journals Total power output generated during dynamic knee extensor exercise at different contraction frequencies

2000 ◽  
Vol 89 (5) ◽  
pp. 1912-1918 ◽  
Author(s):  
Richard A. Ferguson ◽  
Per Aagaard ◽  
Derek Ball ◽  
Anthony J. Sargeant ◽  
Jens Bangsbo
Keyword(s):  
Power Output ◽  
Accurate Determination ◽  
Knee Extensor ◽  
Mechanical Efficiency ◽  
Muscle Group ◽  
Total Power ◽  
Mechanical Power Output ◽  
External Power ◽  
Power Outputs ◽  
Total Power Output

A novel approach has been developed for the quantification of total mechanical power output produced by an isolated, well-defined muscle group during dynamic exercise in humans at different contraction frequencies. The calculation of total power output comprises the external power delivered to the ergometer (i.e., the external power output setting of the ergometer) and the “internal” power generated to overcome inertial and gravitational forces related to movement of the lower limb. Total power output was determined at contraction frequencies of 60 and 100 rpm. At 60 rpm, the internal power was 18 ± 1 W (range: 16–19 W) at external power outputs that ranged between 0 and 50 W. This was less ( P < 0.05) than the internal power of 33 ± 2 W (27–38 W) at 100 rpm at 0–50 W. Moreover, at 100 rpm, internal power was lower ( P < 0.05) at the higher external power outputs. Pulmonary oxygen uptake was observed to be greater ( P< 0.05) at 100 than at 60 rpm at comparable total power outputs, suggesting that mechanical efficiency is lower at 100 rpm. Thus a method was developed that allowed accurate determination of the total power output during exercise generated by an isolated muscle group at different contraction frequencies.

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%.

scholarly journals Simulation of Producer Gas Fired Power Plants with Inlet Fog Cooling and Steam Injection

2006 ◽  
Vol 129 (3) ◽  
pp. 637-647 ◽  
Author(s):  
Mun Roy Yap ◽  
Ting Wang
Keyword(s):  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Power Output ◽  
Power Plants ◽  
Steam Injection ◽  
Combined Cycle ◽  
Producer Gas ◽  
Turbine Inlet ◽  
Cycle Systems

Biomass can be converted to energy via direct combustion or thermochemical conversion to liquid or gas fuels. This study focuses on burning producer gases derived from gasifying biomass wastes to produce power. Since the producer gases are usually of low calorific values (LCV), power plant performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for 5MWe power plants. The power plants considered include simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems using the producer gas with low calorific values at approximately 30% and 15% of the natural gas heating value (on a mass basis). The LCV fuels are shown to impose high compressor back pressure and produce increased power output due to increased fuel flow. Turbine nozzle throat area is adjusted to accommodate additional fuel flows to allow the compressor to operate within safety margin. The best performance occurs when the designed pressure ratio is maintained by widening nozzle openings, even though the turbine inlet pressure is reduced under this adjustment. Power augmentations under four different ambient conditions are calculated by employing gas turbine inlet fog cooling. Comparison between inlet fog cooling and steam injection using the same amount of water mass flow indicates that steam injection is less effective than inlet fog cooling in augmenting power output. Maximizing steam injection, at the expense of supplying the steam to the steam turbine, significantly reduces both the efficiency and the output power of the combined cycle. This study indicates that the performance of gas turbine and combined cycle systems fueled by the LCV fuels could be very different from the familiar behavior of natural gas fired systems. Care must be taken if on-shelf gas turbines are modified to burn LCV fuels.

scholarly journals Cooling Process of Gas Turbine Blade: A Comparison Study

2020 ◽  
Vol 13 (3) ◽  
pp. 215-222
Author(s):  
Akram Luaibi Ballaoot ◽  
Naseer Hamza
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Power Output ◽  
Film Cooling ◽  
Aviation Industry ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet

The gas turbine engines are occupied an important sector in the energy production and aviation industry and this important increase day after day for their features. One of the most important parameters that limit the gas turbine engine power output is the turbine inlet temperature. The higher is the turbine inlet temperature, the higher is the power output or thrust but this increases of risks of blade thermal failure due to metallurgical limits. Thus the need for a good and efficient process of blade cooling can lead to the best compromise between a powerful engine and safe operation. There are two major methods: film or external cooling and internal cooling inside the blade itself. . In the past number of years there has been considerable progress in turbine cooling research and this paper is limited to review a few selected publications to reflect recent development in turbine blade film cooling. The maximum drop in the surface temperature of the gas turbine blade and associated thermal stress – due to incorporating cooling systems- were 735 ˚C, 1217 N/mm2 respectively.

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