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.

Relative Cooling: Part II — Design Considerations and Efficiency

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Cooling System ◽  
High Reliability ◽  
Difficult Problem ◽  
Turbine Engines ◽  
Air Cooling ◽  
Gas Turbine Engines ◽  
Coolant Pump ◽  
Cooling Systems

Abstract Cooling systems with liquid for gas turbine engines that use the relative motion of the engine stator with respect to the rotor for actuating the coolant pump can be encapsulated within the engine rotor. In this manner, the difficult problem of sealing stator/rotor interfaces at high temperature, pressure and relative velocity is circumvented. A first generation of such cooling systems could be manufactured using existing technologies and would boost the thermal efficiency of gas turbine engines by more than 2% compared to recent designs that use advanced air-cooling methods. Later, relative cooling systems could increase the thermal efficiency of gas turbine engines by 8%–11% by boosting the temperatures at turbine inlet to stoichiometric levels and recovering most of the heat extracted from turbine during cooling. The appreciated high reliability of this cooling system will allow widespread use for aerospace propulsion.

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.

A 2000-HP Military Vehicle Gas Turbine: A Study of Significant Thermodynamic and Mechanical Parameters

1968 ◽  
Author(s):  
A. F. Carter
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Overall Design ◽  
Blade Cooling ◽  
Turbine Inlet ◽  
Military Vehicle ◽  
Compressor Pressure Ratio ◽  
Selection Of

During a study of possible gas turbine cycles for a 2000-hp unit for tank propulsion, it has been established that the level of achievable specific fuel consumption (sfc) is principally determined by the combustor inlet temperature. If a regenerative cycle is selected, a particular value of combustor inlet temperature (and hence sfc) can be produced by an extremely large number of combinations of compressor pressure ratio, turbine inlet temperature, and heat exchanger effectiveness. This paper outlines the overall design considerations which led to the selection of a relatively low pressure ratio engine in which the turbine inlet temperature was sufficiently low that blade cooling was not necessary.

Performance Evaluation of Evaporative Compressor Inlet Air Cooling System in a Gas Turbine-Based Cogeneration Plant

2012 ◽  
Author(s):  
Farshid Zabihian ◽  
Alan S. Fung ◽  
Fabio Schuler
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Output Power ◽  
Cooling System ◽  
Air Cooling ◽  
Cogeneration Plant ◽  
Cooling Systems ◽  
Compressor Inlet ◽  
Air Cooling System

Gas turbine-based power plants are very sensitive to ambient conditions and their output power and efficiency can be decreased significantly with increase in the ambient temperature. Various compressor inlet air cooling systems have been proposed and utilized to reduce inlet air temperature to the system, including evaporative systems e.g. media and fogging, and mechanical cooling systems. In this work, different techniques for compressor inlet air cooling are briefly reviewed. Then, the fogging system employed in the Whitby cogeneration power plant is explained with particular attention to the location of the system installation. A model of the gas turbine-based cogeneration plant is also developed to simulate the Whitby cogeneration power plant. The effects of fogging compressor inlet air cooling system on the performance of the plant are investigated. The results indicate that at an ambient temperature of 30°C and relative humidity of 40% the inlet cooling of as high as 8.4°C is possible which can increase output power to more than 50 MW. Also, it is found that the model can predict the gas turbine exhaust temperature and the plant’s power production with the error level of lower than 0.5% and 3%, respectively.

Comparative Thermodynamic Analysis of Gas Turbine Systems with Turbine Blade Film Cooling

2012 ◽  
Vol 505 ◽  
pp. 539-543
Author(s):  
Kyoung Hoon Kim ◽  
Kyoung Jin Kim ◽  
Chul Ho Han
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Thermodynamic Analysis ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Blade Cooling ◽  
Turbine Inlet

Since the gas turbine systems require active cooling to maintain high operating temperature while avoiding a reduction in the system operating life, turbine blade cooling is very important and essential but it may cause the performance losses in gas turbine. This paper deals with the comparative thermodynamic analysis of gas turbine system with and without regeneration by using the recently developed blade-cooling model when the turbine blades are cooled by the method of film cooling. Special attention is paid to investigating the effects of system parameters such as pressure ratio and turbine inlet temperature on the thermodynamic performance of the systems. In both systems the thermal efficiency increases with turbine inlet temperature, but its effect is less sensitive in simpler system

scholarly journals Optimum Power Boosting of Gas Turbine Cycles With Refrigerated Inlet Air and Compressor Intercooling

1996 ◽  
Author(s):  
Mohand A. Ait-Ali
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Inlet Temperature ◽  
Turbine Blade Cooling ◽  
High Pressure Ratio ◽  
Blade Cooling ◽  
Air Inlet ◽  
Turbine Inlet ◽  
Compressor Work

With or without turbine blade cooling, gas turbine cycles have consistently higher turbine inlet temperatures than steam turbine cycles. But this advantage is more than offset by the excessive compressor work induced by warm inlet temperatures, particularly during operation on hot summer days. Instead of seeking still higher turbine inlet temperatures by means of sophisticated blade cooling technology and high temperature-resistant blade materials, it is proposed to greatly increase the cycle net work and also improve thermal efficiency by decreasing the compressor work. This is obtained by using refrigerated inlet air and compressor intercooling to an extent which optimizes the refrigerated air inlet temperature and consequently the gas turbine compression ratio with respect to maximum specific net power. The cost effectiveness of this conceptual cycle, which also includes regeneration, has not been examined in this paper as it requires unusually high pressure ratio gas turbines and compressors, as well as high volumetric air flow rate and low temperature refrigeration equipment for which reliable cost data is not easily available.

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.

scholarly journals Performance Improvements of a Natural Gas Injection Station Using Gas Turbine Inlet Air Cooling

1997 ◽  
Author(s):  
Maurizio De Lucia ◽  
Ennio Carnevale ◽  
Massimo Falchetti ◽  
Alberto Tesei
Keyword(s):  
Gas Turbine ◽  
Performance Enhancement ◽  
Cooling System ◽  
Lithium Bromide ◽  
Capital Outlay ◽  
Air Cooling ◽  
Cooling Systems ◽  
Performance Improvements ◽  
Turbine Inlet ◽  
Air Cooling System

Gas Turbine (GT) performance seriously deteriorates at increased ambient temperature. This study analyses the possibility of improving GT power output and efficiency by installing a gas turbine inlet air cooling system. Different cooling systems were analyzed and preliminary cost evaluations for each system were carried out. The following three cooling systems were considered in detail: a) Traditional compression cooling system; b) Absorption single-acting cooling system using a solution of lithium bromide; c) Absorption double-acting cooling system using a solution of lithium bromide. Results clearly indicate that there is a great potential for GT performance enhancement by application of an Inlet Air Cooling (IAC). Technical and economical analyses lead to selection of a particular type of IAC for significant savings in capital outlay, operational and maintenance costs and other additional advantages.

Exceeding 2000 K at Turbine Inlet: Relative Cooling With Liquid for Gas Turbines — Integrated Systems

2003 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Gas Turbine ◽  
Relative Motion ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Ambient Air ◽  
Air Cooling ◽  
Cooling Systems ◽  
Turbine Inlet

Thermal efficiency of gas turbines is critically dependent on temperature of burnt gases at turbine inlet, the higher this temperature the higher the efficiency. Stochiometric combustion would provide maximum efficiency, but in the absence of an internal cooling system, turbine blades cannot tolerate gas temperatures exceeding 1300 K. This temperature yields a low thermal efficiency, about 15% below the level provide by stoicthiometric combustion. Conventional engines rely on air for blade and disk cooling and limit temperature at turbine inlet to about 1500 K. These engines gain about 3% compared to non-cooled designs. Gas turbines with state of the art air-cooling systems reach up to 1700–1750 K, boosting thermal efficiency by another 2–3%. These temperatures are near the limit allowed by air-cooling systems. Cooling systems with air are easier to design, but air has a low heat transfer capacity, and compressor air bleeding lowers the overall efficiency of engines (less air remains available for combustion). In addition, these systems waste most of the heat extracted from turbine for cooling. In principle, gas turbines could be cooled with liquid. Half a century ago, designers tried to place the pump for coolant recirculation on the engine stator. Liquid was allowed to boil inside the turbine. Seals for parts in relative motion cannot prevent loss of superheated vapors, therefore these experiments failed. To circumvent this problem, another design relied on thermal gradients to promote recirculation from blade tip to root. Liquid flow and cooling capacity were minute. Therefore it was assumed that liquid couldn’t be used for gas turbine cooling. This is an unwarranted assumption. The relative motion between engine stator and rotor provides abundant power for pumps placed on the rotor. The heat exchanger needed for cooling the liquid with ambient air could also be embedded in the rotor. In fact, the entire cooling system can be encapsulated within the rotor. In this manner, the sealing problem is circumvented. Compared to state of the art air-cooling methods, such a cooling system would increase thermal efficiency of any gas turbine by 6%–8%, because stoichimoetric fuel-air mixtures would be used (maybe even with hydrogen fuel). In addition, these systems would recuperate most of the heat extracted from turbine for cooling, are expected to be highly reliable and to increase specific power of gas turbines by 400% to 500%.

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