Effects of Inlet Fogging and Wet Compression on Gas Turbine Performance

Sanaye, Sepehr; Rezazadeh, Hossein; Aghazeynali, Mehrdad; Samadi, Mehrdad; Mehranian, Daryoush; Ahangaran, Mohammad Kazem

doi:10.1115/gt2006-90719

Cited by 11 publications

(14 citation statements)

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“…al. [17] Abdelwahab [18]. The present result of increased specific compressor power due to wet compression, to the authors' knowledge, has not been presented by other researchers in the open literature.…”

Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 52%

“…al. [17] Abdelwahab [18], and Roumeliotis and Mathioudakis [19], but inconsistent with Bagnoli et. al.…”

Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 84%

“…al. [17] also used constant shape factor value to calculate each stage performance and showed that the pressure ratio increases with an increase of injected water amount. Their results showed that both the compressor efficiency and compressor power decrease with an increase of injected water amount.…”

Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 99%

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Overspray and Interstage Fog Cooling in Compressor Using Stage-Stacking Scheme: Part 2—Case Study

Wang

Khan

2008

Volume 7: Education; Industrial and Cogeneration; Marine; Oil and Gas Applications

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A stage-by-stage wet-compression theory and algorithm have been developed for overspray and interstage fogging in the compressor. This theory and algorithm are used to calculate the performance of an 8-stage compressor under both dry and wet compressions. A 2D compressor airfoil geometry and stage setting at the mean radius are employed. Six different cases with and without overspray have been investigated and compared. The stage pressure ratio enhances during all fogging cases as does the overall pressure ratio, with saturated fogging (no overspray) achieving the highest pressure ratio. Saturated fogging reduces specific compressor work, but increases the total compressor power due to increased mass flow rate. The results of overspray and interstage spray unexpectedly show that both the specific and overall compressor power do not reduce but actually increase. Analysis shows this increased power is contributed by increased pressure ratio and, for interstage overspray, "recompression" contributes to more power consumption. Also it is unexpected to see that air density actually decreases, instead of increases, inside the compressor with overspray. Analysis shows that overspray induces an excessive reduction of temperature that leads to an appreciable reduction of pressure, so the increment of density due to reduced temperature is less than decrement of air density affected by reduced pressure as air follows the polytropic relationship. In contrast, saturated fogging results in increased density as expected.After the interstage spray, the local blade loading immediately showed a significantly increase. Fogging increases axial velocity, flow coefficient, blade inlet velocity, incidence angle, and tangential component of velocity. The analysis also assesses the use of an average shape factor in the generalized compressor stage performance curve when the compressor stage information and performance map are not available. The result indicates that using a constant shape factor might not be adequate because the compressor performance map may have changed with wet compression. The results of non-stagestacking simulation are shown to underpredict the compressor power by about 6% and net GT output by about 2% in the studied cases.

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Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 52%

“…al. [17] Abdelwahab [18], and Roumeliotis and Mathioudakis [19], but inconsistent with Bagnoli et. al.…”

Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 84%

Section: Comparison With Previous Studies In Compressor Power Consumpmentioning

confidence: 99%

See 1 more Smart Citation

Overspray and Interstage Fog Cooling in Compressor Using Stage-Stacking Scheme: Part 2—Case Study

Wang

Khan

2008

Volume 7: Education; Industrial and Cogeneration; Marine; Oil and Gas Applications

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“…Due to compression with intercooling, overspray inlet cooling can increase power more than inlet fogging. Chian et al [25] and Sanyaye et al [26,27] studied the effects of evaporative cooling process occurring in both compressor inlet duct (inlet fogging) and inside the compressor (wet compression).…”

Section: Introductionmentioning

confidence: 99%

Exergy Analysis of Overspray Process in Gas Turbine Systems

Kim

2012

Energies

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Gas turbine power can be augmented by overspray process which consists of inlet fogging and wet compression. In this study exergy analysis of the overspray process in gas turbine system is carried out with a non-equilibrium analytical modeling based on droplet evaporation and the second law of thermodynamics. This work focuses on the effects of system parameters such as pressure ratio, water injection ratio, and initial droplet diameter on exergetical performances including irreversibility and exergy efficiency of the process. The process performances are also estimated under the condition of saturated water injection ratio above which complete evaporation of injected water droplets within a compressor is not possible. The results show that the irreversibility increases but the saturated irreversibility decreases with increasing initial droplet diameter for a specified pressure ratio.

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“…Sanaye et al [11] studied the effects of inlet fogging and wet compression on gas turbine performance using the shape factor approach. They modeled the evaporation of water droplets in the compressor inlet duct and estimated the diameter of water droplets at the end of the inlet duct.…”

Section: Introductionmentioning

confidence: 99%

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

Wang

Khan

2015

Journal of Thermal Science and Engineering Applications

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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.

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Effects of Inlet Fogging and Wet Compression on Gas Turbine Performance

Cited by 11 publications

References 0 publications

Overspray and Interstage Fog Cooling in Compressor Using Stage-Stacking Scheme: Part 2—Case Study

Overspray and Interstage Fog Cooling in Compressor Using Stage-Stacking Scheme: Part 2—Case Study

Exergy Analysis of Overspray Process in Gas Turbine Systems

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

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