Impact of Blade Cooling on Gas Turbine Performance Under Different Operation Conditions and Design Aspects

2015 ◽  
Author(s):  
Maryam Besharati-Givi ◽  
Xianchang Li
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Combustion Process ◽  
Inlet Temperature ◽  
Blade Cooling ◽  
Operation Conditions ◽  
Turbine Performance ◽  
Cooling Air ◽  
The Impact ◽  
The Relationship

The increase of power need raises the awareness of producing energy more efficiently. Gas turbine has been one of the important workhorses for power generation. The effects of parameters in design and operation on the power output and efficiency have been extensively studied. It is well-known that the gas turbine inlet temperature (TIT) needs to be high for high efficiency as well as power production. However, there are some material restrictions with high-temperature gas especially for the first row of blades. As a result blade cooling is needed to help balance between the high TIT and the material limitations. The increase of TIT is also limited by restriction of emissions. While the blade cooling can allow a higher TIT and better turbine performance, there is also a penalty since the compressed air used for cooling is removed from the combustion process. Therefore, an optimal cooling flow may exist for the overall efficiency and net power output. In this paper the relationship between the TIT and amount of cooling air is studied. The TIT increase due to blade cooling is considered as a function of cooling air flow as well as cooling effectiveness. In another word, the increase of the TIT is limited while the cooling air can be increased continuously. Based on the relationship proposed the impact of blade cooling on the gas turbine performance is investigated. Compared to the simple cycle case without cooling, the blade cooling can increase the efficiency from 28.8 to 34.0% and the net power from 105 to 208 MW. Cases with different operation conditions such as pressure ratios as well as design aspects with regeneration are considered. Aspen plus software is used to simulate the cycles.

The Impact of Atmospheric Conditions on Gas Turbine Performance

1990 ◽  
Vol 112 (4) ◽  
pp. 590-596 ◽  
Author(s):  
A. A. El Hadik
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Arabian Gulf ◽  
Inlet Temperature ◽  
Atmospheric Conditions ◽  
Design Factor ◽  
Turbine Performance ◽  
The Impact

In a hot summer climate, as in Kuwait and other Arabian Gulf countries, the performance of a gas turbine deteriorates drastically during the high-temperature hours (up to 60°C in Kuwait). Power demand is the highest at these times. This necessitates an increase in installed gas turbine capacities to balance this deterioration. Gas turbines users are becoming aware of this problem as they depend more on gas turbines to satisfy their power needs and process heat for desalination due to the recent technical and economical development of gas turbines. This paper is devoted to studying the impact of atmospheric conditions, such as ambient temperature, pressure, and relative humidity on gas turbine performance. The reason for considering air pressures different from standard atmospheric pressure at the compressor inlet is the variation of this pressure with altitude. The results of this study can be generalized to include the cases of flights at high altitudes. A fully interactive computer program based on the derived governing equations is developed. The effects of typical variations of atmospheric conditions on power output and efficiency are considered. These include ambient temperature (range from −20 to 60°C), altitude (range from zero to 2000 m above sea level), and relative humidity (range from zero to 100 percent). The thermal efficiency and specific net work of a gas turbine were calculated at different values of maximum turbine inlet temperature (TIT) and variable environmental conditions. The value of TIT is a design factor that depends on the material specifications and the fuel/air ratio. Typical operating values of TIT in modern gas turbines were chosen for this study: 1000, 1200, 1400, and 1600 K. Both partial and full loads were considered in the analysis. Finally the calculated results were compared with actual gas turbine data supplied by manufacturers.

Optimum Performance Improvements of the Combined Cycle Based on an Intercooler–Reheated Gas Turbine

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Thamir K. Ibrahim ◽  
M. M. Rahman
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Optimum Level ◽  
Simulation Code ◽  
Operation Conditions ◽  
Turbine Inlet

The performance enhancements and modeling of the gas turbine (GT), together with the combined cycle gas turbine (CCGT) power plant, are described in this study. The thermal analysis has proposed intercooler–reheated-GT (IHGT) configuration of the CCGT system, as well as the development of a simulation code and integrated model for exploiting the CCGT power plants performance, using the matlab code. The validation of a heavy-duty CCGT power plants performance is done through real power plants, namely, MARAFIQ CCGT plants in Saudi Arabia with satisfactory results. The results from this simulation show that the higher thermal efficiency of 56% MW, while high power output of 1640 MW, occurred in IHGT combined cycle plants (IHGTCC), having an optimal turbine inlet temperature about 1900 K. Furthermore, the CCGT system proposed in the study has improved power output by 94%. The results of optimization show that the IHGTCC has optimum power of 1860 MW and thermal efficiency of 59%. Therefore, the ambient temperatures and operation conditions of the CCGT strongly affect their performance. The optimum level of power and efficiency is seen at high turbine inlet temperatures and isentropic turbine efficiency. Thus, it can be understood that the models developed in this study are useful tools for estimating the CCGT power plant's performance.

Gas Turbines Blade Heat Transfer and Internal Swirl Cooling Flow Experimental Study Using Liquid Crystals and Three-Dimensional Stereo-Particle Imaging Velocimetry

2021 ◽  
pp. 1-31
Author(s):  
Daisy Galeana ◽  
Asfaw Beyene
Keyword(s):  
Heat Transfer ◽  
Liquid Crystals ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Convective Heat Transfer Coefficient ◽  
Swirl Flow ◽  
Inlet Temperature ◽  
Cooling Flow ◽  
Blade Cooling ◽  
The Impact

Abstract The challenging engineering intricacies related to improving efficiency of a gas turbine engine comes with the need to maximize the internal cooling of the turbine blade to withstand the high turbine inlet temperature. Understanding the fluid mechanics and heat transfer of internal blade cooling is therefore of paramount importance. This paper presents the impact of swirl cooling flow on the heat transfer of a gas turbine chamber to understand the mechanics of internal blade cooling. The focus is the continuous swirl flow that must be maintained via nonstop injection of tangential flow, whereby swirl flow is generated. The impact of swirl cooling flow variation considers the velocity fields measured using stereo particle image velocimetry, the wall temperature and the convective heat transfer coefficient measured by liquid crystals and system of infrared thermography. Flow behavior and heat transfer at three Reynolds numbers ranging from 7,000 to 21,000 and the average profiles of axial and radial, magnitudes of velocity, and Nusselt numbers are given to research the direct effects of the circular chamber shape. Heat transfer results are measured and collected continuously after the system is heat-soaked to the required temperature. As part of the results relatively low heat transfer rates were observed near the upstream end of the circular chamber, resulting from a low momentum swirl flow as well as crossflow effects. The Thermochromic Liquid Crystal heat transfer results exemplify how the Nu measured favorably at the midstream of the chamber and values decline downstream.

scholarly journals Second Law Approach to the Analysis of Blade Cooling Effects on Gas Turbine Performance

1993 ◽  
Author(s):  
Francesco Farina ◽  
Franco Donatini
Keyword(s):  
Gas Turbine ◽  
Rotor Blades ◽  
Second Law ◽  
Inlet Temperature ◽  
Heavy Duty ◽  
Turbine Inlet Temperature ◽  
Blade Cooling ◽  
Turbine Performance ◽  
Cooling Effects ◽  
Heavy Duty Gas Turbine

A preliminary procedure has been developed to analyse the cooling of both nozzle and rotor blades in a gas turbine, evaluating the influence of the system on the performance of the machine. The developed method, which is based on a second law approach, defines the effects of the thermodynamic losses due to the forced convection air blade cooling on the performance of a typical heavy duty gas turbine in terms of lost exergy as function of the turbine inlet temperature.

Thermodynamic Modeling of Gas Turbine Blade Cooling

2007 ◽  
Author(s):  
Sepehr Sanaye ◽  
Mehdi Darvishi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Modeling ◽  
Continuous Model ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Turbine Performance ◽  
Mass Flow Rates ◽  
Power Outputs ◽  
Cooling Air

Gas turbines are widely used in various industries and the thermal modeling of this equipment is of primary interest to predict its operating condition. One of reasons for deviation of numerical values obtained for actual gas turbine performance and the results obtained from thermal modeling is the effects of blade cooling. In this paper, three blade-cooling models are studied. The first one is the El-Masri continuous model which later modified by Bolland and De Paepe. The Jordal stage-by-stage model and Walsh & Fletcher model are the second and third blade cooling models studied here. The amounts of cooling air mass flow rates estimated by three models are compared for various values of compressor pressure ratios and turbine inlet temperatures for gas turbines in various ranges of power outputs. Furthermore the deviation of key performance parameters predicted by using the above blade cooling models from the actual (reported) corresponding values, was analyzed. It was found that for all three above blade cooling models the deviation was less than three percent for various classes of gas turbines.

scholarly journals The Impact of Changes in Exhaust Temperature on the Power Output and Heat Rate of a Gas Turbine with a Capacity of 238 MW

2021 ◽  
Vol 8 (2) ◽  
pp. 96
Author(s):  
Hendra Budiono Putra Parapa'
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Heat Rate ◽  
Design Data ◽  
Exhaust Temperature ◽  
Turbine Performance ◽  
Actual Design ◽  
Temperature Parameter ◽  
Performance Results ◽  
The Impact

The exhaust temperature parameter is one of the parameters that need to be considered in maintaining the performance of the gas turbine. The purpose of this study is to analyze the effect of changes in exhaust temperature on power output and heat rate. The data used is the actual design data of the M701 gas turbine. This data is used in building the model using the GateCycle software. The modeling simulation results are then validated using the actual design data. To see the impact of changes in exhaust temperature, data from the latest gas turbine performance results are used. This study concludes that changes in exhaust temperature parameters of 1OC have an impact on changes in power output of 0.273% and heat rate of 0.047%.

Parametric Study of Inlet Cooling With Varied COP on Gas Turbine Performance

2014 ◽  
Author(s):  
Maryam Besharati-Givi ◽  
Xianchang Li
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
High Efficiency ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
Inlet Temperature ◽  
Turbine Performance ◽  
Compressor Inlet

Gas turbines play an important role in power generation, and it is therefore desired to operate gas turbines with high efficiency and power output. One of the most influential parameters on the performance of a gas turbine is the ambient condition. It is known that inlet cooling can improve the gas turbine performance, especially when the ambient temperature is high. This study examines the effect of inlet cooling with different operating parameters such as compressor inlet temperature, turbine inlet temperature, air fuel ratio, and pressure ratio. Furthermore, the coefficient of performance (COP) of the cooling system is considered a function of the ambient temperature. Aspen Plus software is used to simulate the system under a steady-flow condition. The results indicate that the cooling of the compressor inlet air can substantially improve the power output as well as the overall efficiency of system. More importantly, there exists an optimal temperature at which the inlet cooling should be operated to achieve the highest efficiency.

Exploring the Impact of Elevated Turbine Blade Cooling Effectiveness and Turbine Material Temperatures on Gas Turbine Engine Performance and Cost

2015 ◽  
Author(s):  
Aaron R. Byerley ◽  
August J. Rolling
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Turbine Blade ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Cooling Effectiveness ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Turbine Inlet ◽  
The Impact

Since the 1950’s, the turbine inlet temperatures of gas turbine engines have been steadily increasing as engine designers have sought to increase engine thrust-to-weight and reduce fuel consumption. In turbojets and low-bypass turbofan engines, increasing the turbine inlet temperature boosts specific thrust, which in some cases can support supersonic flight without the use of an afterburner. In high-bypass gas turbine engines, increasing the turbine inlet temperature makes possible higher bypass ratios and overall pressure ratios, both of which reduce specific fuel consumption. Increased turbine inlet temperatures, without sacrificing blade life, have been made possible through advances in blade cooling effectiveness and high-temperature turbine blade materials. Investigating the impact of higher turbine inlet temperatures and the corresponding cooling air flow rates on specific thrust, specific fuel consumption, and engine development cost is the subject of this paper. A physics-based cooling effectiveness correlation is presented for linking turbine inlet temperature to cooling flow fraction. Two cases are considered: 1) a low-bypass, mixed-exhaust, non-afterburning turbofan engine intended to support supercruising at Mach 1.5 and 2) a high-bypass, unmixed-exhaust turbofan engine intended to support highly efficient, long range flight at Mach 0.8. For each of these two cases, both baseline and enhanced cooling effectiveness values as well as both baseline and elevated turbine blade material temperatures are considered. Comparing these cases will ensure that students taking courses in preliminary engine design understand why huge research investments continue to be made in turbine blade cooling and advanced, high-temperature turbine blade material development.

Effect of New Blade Cooling System With Minimized Gas Temperature Dilution on Gas Turbine Performance

1984 ◽  
Vol 106 (4) ◽  
pp. 756-764 ◽  
Author(s):  
K. Kawaike ◽  
N. Kobayashi ◽  
T. Ikeguchi
Keyword(s):  
Gas Turbine ◽  
Cooling System ◽  
High Reliability ◽  
Pressure Ratio ◽  
Growth Potential ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Cooling Systems ◽  
Blade Cooling ◽  
Turbine Performance

Recent developments in high-performance and high-reliability gas turbine engines necessitate enforced cooling to maintain the blade temperature at reasonably low levels associated with increased turbine inlet temperature and compressor pressure ratio. However, the gas turbine performance is strongly penalized by the consumption of cooling flow, resulting in temperature dilution of hot mainstream, aerodynamic mixing loss, and pumping power loss. In this paper, a new practical blade cooling system using state-of-the-art engineering, which aims at minimizing the dilution effect, is presented. Trade-off studies between performance and reliability in terms of blade metal temperature are performed to evaluate cooling systems. Analytical comparison of different cooling systems demonstrates that the proposed cooling system provides significant improvements in performance gain and growth potential over conventional air cooling systems.

Thermodynamic Analysis of Gas Turbine Performance With Different Inlet Air Cooling Techniques

2012 ◽  
Author(s):  
Ana Paula Pereira dos Santos ◽  
Claudia Regina de Andrade
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Mass Flow Rate ◽  
Air Temperature ◽  
Flow Rate ◽  
Power Output ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Turbine Performance ◽  
Unit Energy

For geographic regions where significant power demand and highest electricity prices occur during the warm months, a gas turbine inlet air cooling technique is a useful option for increasing output. Inlet air cooling increases the power output by taking advantage of the gas turbine’s feature of higher mass flow rate, due the compressor inlet temperature decays. Industrial gas turbines that operate at constant speed are constant-volume-flow combustion machines. As the specific volume of air is directly proportional to the temperature, the increases of the air density results in a higher air mass flow rate once the volumetric rate is constant. Consequently, the gas turbine power output enhances. Different methods are available for reducing compressor intake air temperature. There are two basic systems currently available for inlet cooling. The first and most cost-effective system is evaporative cooling. Evaporative coolers make use of the evaporation of water to reduce the gas turbine inlet air temperature. The second system employs two ways to cool the inlet air: mechanical compression and absorption. In this method, the cooling medium flows through a heat exchanger located in the inlet duct to remove heat from the inlet air. In the present study, a thermodynamic analysis of gas turbine performance is carried out to calculate heat rate, power output and thermal efficiency at different inlet air temperature and relative humidity conditions. The results obtained with this model are compared with the values of the condition without cooling herein named of Base-Case. Then, the three cooling techniques are computationally implemented and solved for different inlet conditions (inlet temperature and relative humidity). In addition, the gas turbine was performed under different cooling methods applied for two Brazilian sites, the comparison between chiller systems (mechanical and absorption) showed that the absorption chiller provides the highest increment in annual energy generation with lower unit energy costs. On the other hand, evaporative cooler offers the lowest unit energy cost but associated with a limited cooling potential.

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