Suppressing the Infrared Signatures of Marine Gas Turbines

1989 ◽  
Vol 111 (1) ◽  
pp. 123-129 ◽  
Author(s):  
A. M. Birk ◽  
W. R. Davis
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Metal Surfaces ◽  
Power Plants ◽  
Exhaust System ◽  
Ambient Conditions ◽  
Ir Radiation ◽  
Gravity Effects ◽  
Black Bodies ◽  
Department Of National Defence

The exhaust plumes and visible areas of the engine exhaust ducting associated with marine gas turbines are major sources of infrared (IR) radiation on ships. These high-radiance sources make excellent targets for IR-guided threats. In recent years significant efforts have been made to reduce or eliminate these high-radiance sources to increase the survivability of naval and commercial ships when sailing in high-risk areas of the world. Typical IR signature suppression (IRSS) systems incorporate film cooling of visible metal sources, optical blockage to eliminate direct line-of-sight visibility of hot exhaust system parts, and cooling air injection and mixing for plume cooling. Because the metal surfaces radiate as near black bodies, every attempt is made to reduce the temperatures of the visible surfaces to near ambient conditions. The exhaust gases radiate selectively and therefore do not have to be cooled to the same degree as the metal surfaces. The present paper briefly describes the motivation for incorporating IRSS into the exhaust systems of marine power plants. IRSS hardware developed in Canada by the Canadian Department of National Defence and Davis Engineering Limited is presented along with details of their operating principles. A typical installation is presented and discussed. Design impacts on the ship are described with reference to engine back pressure, noise, and weight and center of gravity effects.

Influence of Ambient Conditions on an Aeroderivative Gas Turbine Based Cogeneration Plant — A Comparison of Numerical Simulation With Field Performance Data

2000 ◽  
Author(s):  
Carlo Carcasci ◽  
Bruno Facchini ◽  
Francesco Grillo
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Field Performance ◽  
Performance Data ◽  
Plant Performance ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Compressor Inlet

Gas turbine performances are directly related to outside conditions. The use of gas turbines in combined gas-steam power plants, also applied to cogeneration, increases performance dependence by outside conditions, because plants boundary conditions become more complex. In recent years, inlet air cooling systems have been introduced to control air temperature and humidity at compressor inlet resulting in an increase in plant power and efficiency. In this paper, the dependence of outside conditions for an existing cogenerative plant, located in Tuscany (Italy), is studied. The plant is equipped with two GE-LM6000 aeroderivative gas-turbines coupled with a three pressure level heat recovery steam generator, cogenerative application being related to the industrial district. The ambient temperature has been found to be the most important factor affecting the plant performance, but relative air humidity variation also has considerable effects. The field performance data are compared with a numerical simulation. The simulation results show a good agreement with the field performance data. The simulation allows evaluation of design and off-design plant performance and can become a useful tool to study the outside condition influence on power plant performance.

Through-Flow Modeling of Single- and Two-Shaft Gas Turbines at Wide Operating Range

2018 ◽  
Author(s):  
Alexander Wiedermann ◽  
Milan V. Petrovic
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Thermodynamic Cycle ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Coupled Analysis ◽  
Ambient Conditions ◽  
Gas Treatment ◽  
Through Flow ◽  
End Wall

A program suite of coupled analysis tools for all components of industrial gas turbines developed by the authors was applied to off-design operation of single- and two-shaft gas turbines. The through-flow methods are based on a stream function approach and a finite element solution procedure. They include high-fidelity loss and deviation models with improved correlations. Advanced radial mixing and end-wall boundary layer models were applied to simulate 3D flow effects. For air-cooled turbine analysis, various types of cooling air injection were encompassed: film cooling, trailing edge injection and disc/end-wall coolant flow. Several improvements and extensions of the meridional solvers involved were employed. For axial compressor analysis, the original perfect gas treatment was replaced with the same real gas library that had already been implemented for flow computations in air-cooled expansion turbines and combustion modules. Ambient conditions with wet inflow of the compressor can now be taken into account. Compared to the previous model, better closure of the thermodynamic cycle can be achieved with the new approach. The meridional flow solver applied to the cooled turbine was upgraded and has become more stable for transonic outlet Mach numbers. With regard to the cooling flow supply, the codes offer greater freedom at the compressor extraction and turbine injection stations, allowing more realistic modeling of the secondary flow bifurcation. Off-design operating conditions and sensitivity studies for both single- and two-shaft gas turbines covering the entire range of interest are presented and are compared with experimental rig-engine data where available.

Power Augmentation Study of an Existing Combined Cycle Power Plant by Overspray Inlet Fogging

2008 ◽  
Author(s):  
Hsiao-Wei D. Chiang ◽  
Pai-Yi Wang ◽  
Hsin-Lung Li
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Peak Load ◽  
Combined Cycle ◽  
Ambient Conditions ◽  
Combined Cycle Power Plant ◽  
Combined Cycles ◽  
Increasing Demand

With increasing demand for power and with shortages envisioned especially during the peak load times during the summer, there is a need to boost gas turbine power. In Taiwan, most of gas turbines operate with combined cycle for base load. Only a small portion of gas turbines operates with simple cycle for peak load. To prevent the electric shortage due to derating of power plants in hot days, the power augmentation strategies for combined cycles need to be studied in advance. As a solution, our objective is to add an overspray inlet fogging system into an existing gas turbine-based combined cycle power plant (CCPP) to study the effects. Simulation runs were made for adding an overspray inlet fogging system to the CCPP under various ambient conditions. The overspray percentage effects on the CCPP thermodynamic performance are also included in this paper. Results demonstrated that the CCPP net power augmentation depends on the percentage of overspray under site average ambient conditions. This paper also included CCPP performance parametric studies in order to propose overspray inlet fogging guidelines for combined cycle power augmentation.

scholarly journals Gas Turbine Spinning Reserve Operation to Support Frequency Drops in Small Grid

1998 ◽  
Author(s):  
Ismael Brito ◽  
Michael Dost ◽  
Axel W. von Rappard
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Exhaust System ◽  
Spinning Reserve ◽  
Control Functions ◽  
Load Increase ◽  
The Stability ◽  
Grid Side ◽  
Gas Turbine Power Plant

The use of gas turbines in relatively small grids is often connected with an additional requirement from the grid side. Such a requirement can be the increase of power production within seconds to support the stability of a grid. This topic was investigated thoroughly in 1985 for several types of power plants. In 1992 ABB received an order for a gas turbine power plant on the island of Puerto Rico where a fast loading response with 40% load increase within 3 seconds was required. Based on earlier investigations the order was accepted. The powerplant built a „Steam Enhanced Power (SEP) plant“, each consisting of three powertrains each with a gas turbine, a once through steam generator and an exhaust system with an SCR for emission control. This paper describes the control functions necessary to meet the requirements and the consequences for the operation of the plant. Results from the acceptance tests where the rapid loading from a standby mode at 60% load was simulated will be shown and discussed in detail.

Prediction of Low Temperature Hot Corrosion Rate in Film Cooled Coal Fired Gas Turbines

2003 ◽  
Author(s):  
Vaidyanathan Krishnan ◽  
Sanjeev Bharani ◽  
J. S. Kapat ◽  
Y. H. Sohn ◽  
V. H. Desai
Keyword(s):  
Corrosion Rate ◽  
Hot Corrosion ◽  
Film Cooling ◽  
Gas Turbines ◽  
Power Plants ◽  
Gas Temperature ◽  
Air Temperatures ◽  
Operational Life ◽  
Cooling Hole ◽  
Cooling Air

The concept of coal based gas turbine power plants has drawn considerable interest in recent years. Coal or syngas based power plants like IGCC have shown significant potential for meeting the ever-increasing power demands as well as stricter environmental regulations. The trouble free operational life of such power plants is limited by a major factor namely hot corrosion of the turbine components. Hitherto, the mechanism of hot corrosion has been investigated in a simpler context, which is not directly applicable to gas turbines in the presence of film cooling techniques. The present paper is an attempt to model hot corrosion in the presence of film cooling relevant to gas turbines, using a simple resistance model and the inherent analogy between heat and mass transfer. This paper considers film cooling air temperatures in the range of 450°C to 550°C, and a free stream gas temperature of 1425°C, with 0.5% sulfur in the fuel. For lower cooling air temperatures (less than 500°C), film cooling air suppresses corrosion, whereas for higher cooling air temperature corrosion rate is more in the presence of film cooling. With film cooling, there is a sharp peak in corrosion rate close to the cooling hole (within 10 slot widths). Due to the possibility that the base superalloy may be exposed in this region, designers should consider the high corrosion rate seriously. However, the present model is limited in its prediction because of its simplicity. Further improvement of the model is essential for optimization purposes.

Conjugate Heat Transfer and Film Cooling of a Multi-Stage Cooling Scheme

2008 ◽  
Author(s):  
M. Ghorab ◽  
S. I. Kim ◽  
I. Hassan
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Density Ratio ◽  
Design Parameters ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Multi Stage ◽  
Internal Gap

Cooling techniques play a key role in improving efficiency and power output of modern gas turbines. The conjugate technique of film and impingement cooling schemes is considered in this study. The Multi-Stage Cooling Scheme (MSCS) involves coolant passing from inside to outside turbine blade through two stages. The first stage; the coolant passes through first hole to internal gap where the impinging jet cools the external layer of the blade. Finally, the coolant passes through the internal gap to the second hole which has specific designed geometry for external film cooling. The effect of design parameters, such as, offset distance between two-stage holes, gap height, and inclination angle of the first hole, on upstream conjugate heat transfer rate and downstream film cooling effectiveness performance are investigated computationally. An Inconel 617 alloy with variable properties is selected for the solid material. The conjugate heat transfer and film cooling characteristics of MSCS are analyzed across blowing ratios of Br = 1 and 2 for density ratio, 2. This study presents upstream wall temperature distributions due to conjugate heat transfer for different gap design parameters. The maximum film cooling effectiveness with upstream conjugate heat transfer is less than adiabatic film cooling effectiveness by 24–34%. However, the full coverage of cooling effectiveness in spanwise direction can be obtained using internal cooling with conjugate heat transfer, whereas adiabatic film cooling effectiveness has narrow distribution.

Recent Advances in the Study of Film Cooling on the Gas Turbine Blade

2014 ◽  
Vol 971-973 ◽  
pp. 143-147 ◽  
Author(s):  
Ping Dai ◽  
Shuang Xiu Li
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbines ◽  
High Performance ◽  
Leading Edge ◽  
Development Trend ◽  
Research Progress ◽  
Gas Turbine Blade ◽  
New Generation

The development of a new generation of high performance gas turbine engines requires gas turbines to be operated at very high inlet temperatures, which are much higher than the allowable metal temperatures. Consequently, this necessitates the need for advanced cooling techniques. Among the numerous cooling technologies, the film cooling technology has superior advantages and relatively favorable application prospect. The recent research progress of film cooling techniques for gas turbine blade is reviewed and basic principle of film cooling is also illustrated. Progress on rotor blade and stationary blade of film cooling are introduced. Film cooling development of leading-edge was also generalized. Effect of various factor on cooling effectiveness and effect of the shape of the injection holes on plate film cooling are discussed. In addition, with respect to progress of discharge coefficient is presented. In the last, the future development trend and future investigation direction of film cooling are prospected.

Experimental Evaluation of Compressor Blade Fouling

2016 ◽  
Author(s):  
Rainer Kurz ◽  
Grant Musgrove ◽  
Klaus Brun
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
Blade Surface ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Compressor Blades ◽  
Performance Deterioration ◽  
Quantitative Results ◽  
The Impact ◽  
Dust Retention

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on performance, as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions of the blade surface. Quantitative results both indicate the amount of dust as well as the distribution of dust on the airfoil, for a dry airfoil, as well as airfoils that were wet from ingested water, as well as different types of oil. The retention patterns are correlated with the boundary layer shear stress. The tests show the higher dust retention from wet surfaces compared to dry surfaces. They also provide information about the behavior of the particles after they impact on the blade surface, showing that for a certain amount of wet film thickness, the shear forces actually wash the dust downstream, and off the airfoil. Further, the effect of particle agglomeration of particles to form larger clusters was observed, which would explain the disproportional impact of very small particles on boundary layer losses.

Inlet Air Cooling Applied to Combined Cycle Power Plants: Influence of Site Climate and Thermal Storage Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nicola Palestra ◽  
Giovanna Barigozzi ◽  
Antonio Perdichizzi
Keyword(s):  
Power Output ◽  
Parametric Analysis ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Storage ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Cooling Systems

The paper presents the results of an investigation on inlet air cooling systems based on cool thermal storage, applied to combined cycle power plants. Such systems provide a significant increase of electric energy production in the peak hours; the charge of the cool thermal storage is performed instead during the night time. The inlet air cooling system also allows the plant to reduce power output dependence on ambient conditions. A 127MW combined cycle power plant operating in the Italian scenario is the object of this investigation. Two different technologies for cool thermal storage have been considered: ice harvester and stratified chilled water. To evaluate the performance of the combined cycle under different operating conditions, inlet cooling systems have been simulated with an in-house developed computational code. An economical analysis has been then performed. Different plant location sites have been considered, with the purpose to weigh up the influence of climatic conditions. Finally, a parametric analysis has been carried out in order to investigate how a variation of the thermal storage size affects the combined cycle performances and the investment profitability. It was found that both cool thermal storage technologies considered perform similarly in terms of gross extra production of energy. Despite this, the ice harvester shows higher parasitic load due to chillers consumptions. Warmer climates of the plant site resulted in a greater increase in the amount of operational hours than power output augmentation; investment profitability is different as well. Results of parametric analysis showed how important the size of inlet cooling storage may be for economical results.

Effect of Film Cooling on Low Temperature Hot Corrosion in a Coal Fired Gas Turbine

2003 ◽  
Author(s):  
Vaidyanathan Krishnan ◽  
J. S. Kapat ◽  
Y. H. Sohn ◽  
V. H. Desai
Keyword(s):  
Low Temperature ◽  
Corrosion Rate ◽  
Hot Corrosion ◽  
Film Cooling ◽  
Gas Turbines ◽  
Primary Source ◽  
Operating Conditions ◽  
Coal Gas ◽  
A Chain ◽  
Lower Corrosion Rate

In recent times, the use of coal gas in gas turbines has gained a lot of interest, as coal is quite abundant as a primary source of energy. However, use of coal gas produces a few detrimental effects that need closer attention. This paper concentrates on one such effect, namely hot corrosion, where trace amounts of sulfur can cause corrosion (or sulfidation) of hot and exposed surfaces, thereby reducing the life of the material. In low temperature hot corrosion, which is the focus of this paper, transport of SO2 from the hot gas stream is the primary process that leads to a chain of events, ultimately causing hot corrosion. The corrosion rate depends on SO2 mass flux to the wall as well as wall surface temperature, both of which are affected in the presence of any film cooling. An analytical model is developed to describe the associated transport phenomena of both heat and mass in the presence of film cooling The model predicts how corrosion rates may be affected under operating conditions. It is found that although use of film cooling typically leads to lower corrosion rate, there are combinations of operating parameters under which corrosion rate can actually increase in the presence of film cooling.

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