Values Of Turbine Inlet Temperature Research Articles

The Impact of Atmospheric Conditions on Gas Turbine Performance.(Dept.M)

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(reaches up to 60 oC IN Kuwait). This occurs when the power demand is the largest. This necessitates the increase of the gas turbine installed capacities to balance this deterioration Gas turbines users are becoming aware of this problem as they depend more or gas turbines to satisfy their needs of power and process heat for desalination due to the recent circuit and economical development of the gas turbines. This paper is devoted to study the impact of atmospheric conditions, such as ambient temperature, pressure, and relative humidity on gas turbine performance, The reason for considering the air pressures different than standard atmospheric pressure of the compressor inlet is the variation of this pressure with the altitude. This can generalize the results of this study to include the cases flights at high altitudes. A fully interactive computer programme based on the derived governing equations is developed. The effects of typical variations of atmospheric conditions on the power output and efficiency are considered. These include ambient temperature (range from 20 to 60oC), altitude (range from zero to 2000 m above sea level) and relative humidity (range from zero to 100%). 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 which 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. Partial loads were also considered in the analysis as well as full load. Finally the calculated results were compared with the actual gas turbine data supplied by manufacturers.

Performance Optimization of Combined Cycle Power Plant Considering Various Operating Parameters

Combined cycle power plants are popular in the thermal engineering field for their higher efficiency as compared to normal cycles such as Rankine and Brayton Cycle. But main disadvantages of the cycle are waste heat rejection and low work output. To overcome these difficulties a heat recovery system is used in the present work to recover waste heat of the Brayton cycle as a steam generator for the Rankine cycle in a combined Gas-Vapor cycle. In the present work, the effect of factors such as “compression ratio”, “inlet air temperature” and “turbine inlet temperature” on cycle efficiency was calculated. It was found that cycle efficiency increases with increase in these factors. It was found that the optimum value of compression ratio is 12-18 for maximum output of combined cycle. Whereas inlet air temperature has adverse effect on cycle efficiency so it should be kept lower while increase in turbine inlet temperature increases the cycle’s work output and hence efficiency. Optimum values of turbine inlet temperature were found in the range of 1600-1700 K

Comprehensive Performance Analysis of the Turbofan With a Multi-Annular Rotating Detonation Duct Burner

Abstract The performance analysis of mixed-exhaust turbofan engine with multi-annular rotating detonation duct burner (RDDB) is conducted for the first time, considering that the flow path of the bypass duct is ideal for a rotating detonation combustor (RDC). The configuration of the multi-annular rotating detonation combustor is constructed aiming at the advantages of a wider operation range and uniform outlet parameters over the single-annular one. Then, a parametric analysis model of the mixed-exhaust turbofan engine with a rotating detonation duct burner is developed. Thereafter, the effects of duct burner parameters on the engine performance and operating characteristics are investigated. The mixed-exhaust turbofan engine with a rotating detonation duct burner shows superior overall performance to that of one with an isobaric afterburner (ICAB) over a wide operation range. The separate-exhaust rotating detonation duct burner can hold characteristics that are higher than those of the mixed-exhaust one at lower values of fan pressure ratio, while the mixed-exhaust one corresponds to lower values of turbine inlet temperature. When the rotating detonation duct burner is “on,” the low-pressure rotor operating line moves toward the surge line on the low corrected shaft speed side but away from the surge line on the high corrected shaft speed side.

Gas Turbine Fouling: A Comparison Among 100 Heavy-Duty Frames

Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g., natural gas) have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum, or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature (TIT) of (1400–1500) °C, which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape, and clog the coolant passages. At the same time, land-based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency, and TIT with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on 100 gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.

Effect of heat leakage on the performance of a twin-spool turbofan engine

The effect of heat leakage from a twin-spool turbofan engine to the ambient air on the performance of the engine for a commercial aircraft is investigated. Effects of heat leakage on the variation of the performance indicators of coefficient of ecological performance, overall efficiency, exergy destruction factor, thrust specific fuel consumption and entropy generation rate with respect to the design parameters of compressor and fan pressure ratios, by-pass ratio and turbine inlet temperature are investigated numerically. The main findings are as follows: (i) Effect of heat leakage from the combustion chamber to the by-pass air on the coefficient of ecological performance, exergy destruction factor and entropy generation rate is considerably large when compared to that on the other performance indicators especially for small values of design parameters except for turbine inlet temperature. (ii) Effect of heat leakage on the performance indicators is significant for small values of turbine inlet temperature and large values of the other design parameters.

Numerical Study of a Micro Gas Turbine Fed by Liquid Fuels: Potentialities and Critical Issues

Aim of the paper is to evaluate the potentialities and critical issues of the micro-gas turbine Turbec T100 properly modified in order to be powered by liquid fuels. The main difference with respect to the version designed for gaseous fuels concerns the combustor, namely the combustion chamber and the fuel injection system. The numerical study was carried out using both a 0D matching analysis and a 3D CFD analysis of the combustor. The thermodynamic model, coupled with the operating maps of rotating components, was calibrated using the experimental data collected during operation of the micro-gas turbine with gaseous fuel. The operative parameters computed through the 0D model have been utilized to simulate the behavior of micro-gas turbine fed by liquid fuels, thus obtaining the initial and boundary conditions to be used in the CFD analysis. The combustion process of liquid fuels is analyzed; the main differences at varying loads are discussed in terms of temperature and velocity profiles of the air flows inside the combustion chamber and mean values of turbine inlet temperature and exhaust gaseous concentration. A preliminary study concerning the characteristics of the injection system is also reported.

Advanced exergy and environmental analyses and multi objective optimization of a real combined cycle power plant with supplementary firing using evolutionary algorithm

This paper deals with an advanced exergy analysis and optimization of a real CCPP (combined cycle power plant) with DBs (duct burners) located in Iran. The endogenous/exogenous exergy destruction parts of each component as well as their combinations with avoidable/unavoidable parts are determined. A parametric study is carried out to assess the sensitivity of total avoidable exergy destruction and CO2 emission to TIT (turbine inlet temperature), compressor pressure ratio (rc) and DB fuel mass flow rate (m˙DB). Parametric results reveal that the increments in TIT and rc improve the CO2 emissions by about 6.8% and 17%, respectively and the total avoidable exergy destruction rate increases within 19% when rc is in the range of 9–14. In addition, NSGA-II (Non-dominated Sort Genetic Algorithm-II) is applied to obtain the final solutions in the multi-objective optimization of the CCPP. The optimum value of total avoidable exergy destruction rate and CO2 emission indicates 10.6% and 8.3% improvements, respectively, relative to the base case. Furthermore, the values of TIT and m˙DB decrease to 1.7% and 32.5%, respectively and rc increases 38% compared with the base case.

Analysis of Combined Effects of Air Transpiration Cooling and Evaporative Inlet Air Cooling on the Performance Parameters of a Simple Gas Turbine Cycle

This paper is focused on accessing the benefits of incorporating an air humidifier with a cooled gas turbine cycle. Air transpiration cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor pressure ratio (rp,c), compressor inlet temperature (CIT), turbine inlet temperature (TIT), inlet temperature ratio (rIT), ambient relative humidity, and ambient temperature on performance parameters of plant has been carried out. Evaporative inlet air cooling has been observed to improve the plant efficiency of a transpiration cooled gas turbine plant by 4.84% and plant specific work by 9.68% at an ambient temperature of 313 K and ambient relative humidity of 0.2. The effects of variation of ambient parameters on cycle performance are found to be more pronounced at higher turbine inlet temperature and higher compression ratio (rp,c). The work ratio increases with an increase in the value of rIT up to 5.6 after which it decreases. There exists an optimum rIT at any rp,c with reference to the maximum work ratio. The heat rate increases with an increase in rIT and a decrease in rp,c. For all values of TIT there exists an optimum rp,c at which plant efficiency is at its maximum.

Numerical cost optimization and irreversibility analysis of the triple-pressure reheat steam-air cooled GT commercial combined cycle power plants

Abstract Steam-air cooling of the gas turbine (GT) and optimization are important methods for enhancing the efficiency and power of the combined cycle power plants. A steam-air cooled GT uses less air for GT cooling; thus, allows more air to be available for the combustion process and increases output power significantly. In this paper, the commercial triple-pressure reheat steam-air cooled GT combined cycles (The GE Stage 107H and Mitsubishi M501H commercial combined cycles) were presented, optimized relative to its operating parameters, and the irreversibilities of the components were analyzed to identify the magnitude and locations of such irreversibilities and discuss its causes. Constraints were set on many operating parameters such as air pressure ratio, the ratio of the cooling steam flow to the maximum available flow for steam cooling, and stack temperature. The net revenue and cycle efficiency were optimized at 10 different maximum values of turbine inlet temperature (TIT) using two different methods: the direct search and variable metric. The optimized cycles had better performance and lower irreversibilities for the main components than that for the commercial cycles. Optimizing the net revenue could result in an annual saving of about 29.2 million US dollars for a 400 MW power plant.

Cost numerical optimization of the triple-pressure steam-reheat gas-reheat gas-recuperated combined power cycle that uses steam for cooling the first GT

Optimization is an important method for improving the efficiency and power of the combined cycle. In this paper, the triple-pressure steam-reheat gas-reheat gas-recuperated combined cycle that uses steam for cooling the first gas turbine (the regular steam-cooled cycle) was optimized relative to its operating parameters. The optimized cycle generates more power and consumes more fuel than the regular steam-cooled cycle. An objective function of the net additional revenue (the saving of the optimization process) was defined in terms of the revenue of the additional generated power and the costs of replacing the heat recovery steam generator (HRSG) and the costs of the additional operation and maintenance, installation, and fuel. Constraints were set on many operating parameters such as air compression ratio, the minimum temperature difference for pinch points (δTppm), the dryness fraction at steam turbine outlet, and stack temperature. The net additional revenue and cycle efficiency were optimized at 11 different maximum values of turbine inlet temperature (TIT) using two different methods: the direct search and the variable metric. The optima were found at the boundaries of many constraints such as the maximum values of air compression ratio, turbine outlet temperature (TOT), and the minimum value of stack temperature. The performance of the optimized cycles was compared with that for the regular steam-cooled cycle. The results indicate that the optimized cycles are 1.7–1.8 percentage points higher in efficiency and 4.4–7.1% higher in total specific work than the regular steam-cooled cycle when all cycles are compared at the same values of TIT and δTppm. Optimizing the net additional revenue could result in an annual saving of 21 million U.S. dollars for a 439 MW power plant. Increasing the maximum TOT to 1000°C and replacing the stainless steel recuperator heat exchanger of the optimized cycle with a super-alloys-recuperated heat exchanger could result in an additional efficiency increase of 1.1 percentage point and a specific work increase of 4.8–7.1%. The optimized cycles were about 3.3 percentage points higher in efficiency than the most efficient commercially available H-system combined cycle when compared at the same value of TIT. Copyright © 2008 John Wiley & Sons, Ltd.

Modelling, analysis, and irreversibility reduction of the triple-pressure reheat H-system combined cycle

The triple-pressure reheat H-system combined cycle is considered the most efficient combined cycle that is commercially available. The gas turbine of the H-system combined cycle is cooled using a closed loop of steam and an open loop of air. Compared with the regular triple-pressure reheat combined cycle, the heat recovery steam generator (HRSG) of the H-system has a different configuration and a reduced load since superheating of steam is partially performed by the gas turbine. In this paper, the triple-pressure reheat H-system combined cycle was modelled, including detailed modelling of the HRSG and the expansion and cooling processes of the gas turbine. The performance of the H-system combined cycle was analysed and a feasible technique to reduce the irreversibility of the HRSG was introduced. The reduced-irreversibility triple-pressure reheat steam-air gas turbine-cooled (H-system) combined cycle was compared with the regularly designed triple-pressure reheat H-system combined cycle, which is the typical design for a commercial combined cycle. The effects of varying the turbine inlet temperature (TIT) on the performance of all cycles were presented and discussed. The results indicate that the reduced-irreversibility H-system combined cycle is 1.45–1.65 per cent higher in efficiency and 2.5 per cent higher in the total specific work than the regularly designed H-system combined cycle when all compared at the same values of TIT and minimum temperature difference for pinch points (PPm)- The reduced-irreversibility H-system combined cycle was 1.35 per cent higher in efficiency than the most efficient commercially available H-system combined cycle when compared at the same value of TIT. Economical analysis of the reduced-irreversibility cycle was performed and showed that applying the introduced technique could result in an annual saving of ten million US dollars for a 440 MW power plant.

The Impact of Atmospheric Conditions on Gas Turbine Performance

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.