scholarly journals The energy analysis of GE-F5 gas turbines inlet air–cooling systems by the off-design method

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1489-1498
Author(s):  
Seyed Mehdi Arabi ◽  
Hossein Ghadamian ◽  
Mohammad Aminy ◽  
Hassan Ali Ozgoli ◽  
Behzad Ahmadi ◽  
...  
Keyword(s):  
Air Temperature ◽  
Gas Turbines ◽  
Design Method ◽  
Characteristic Curve ◽  
Air Cooling ◽  
Cooling Systems ◽  
Normal Cycle ◽  
Turbine Cooling ◽  
Efficiency Increase ◽  
Gas Power Plant

Increasing the inlet air temperature causes a reduction in the air mass flow rate, and the efficiency and output power of a gas power plant will reduced. To compensate this power and efficiency decrease, different cooling systems can be applied to the inlet air flow. This paper introduces and analyzes different gas turbine cooling systems and studies their effect on the efficiency of Zanbagh power plant’s G11 gas unit by extracting the governing equations regarding the characteristic curve and coding in the MATLAB software. In average, the simulation results show that reduction of 1 °C of inlet air temperature between 14 °C and 50 °C causes an efficiency and power output increase by 0.085% and 0.16 MW, respectively. The maximum cycle efficiency increase applied to cool the inlet air is around 2.7%, which can be achieved using the wet compression method. In addition, this method can reduce fuel consumption by 5% in comparison to a normal cycle.

scholarly journals Energy performance analysis of GE-F5 gas turbines at off-design conditions by applying an innovative convergent–divergent system for the inlet air cooling

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1508-1516
Author(s):  
Seyed Mehdi Arabi ◽  
Hossein Ghadamian ◽  
Mohammad Aminy ◽  
Hassan Ali Ozgoli ◽  
Behzad Ahmadi ◽  
...  
Keyword(s):  
Output Power ◽  
Air Temperature ◽  
Gas Turbines ◽  
Power Plants ◽  
Characteristic Curve ◽  
Ambient Air ◽  
Energy Performance ◽  
Air Cooling ◽  
Design Algorithm ◽  
Ambient Air Temperature

Ambient air temperature increase, in a gas power plant, causes the intake air mass flow rate to be decreased and can have a significant reducing effect on output power and efficiency. To compensate for this reduction, at different climate conditions, various systems can be used to cool the inlet air. To predict the performance of a gas turbine at off-design conditions (by changing surrounding conditions and/or the air cooling method), modeling of the unit performance is required. Due to the high consumption of water and electricity in the conventional cooling systems, in this paper, in addition to introducing an off-design algorithm, governing equations of each cycle elements were inferenced by their characteristic curve. By developing code in MATLAB software, the effect of applying a novel convergent–divergent system on GE-F5 gas units in Yazd Zanbagh power plants was studied. The results show that in a temperature range between 14 and 50 °C, for each degree decrease in ambient air temperature, an approximately 8.99 kW increase in output power can be obtained. The main advantage of this system is the capability of its application in both dry and humid regions. In addition, the refrigerant medium is not required, which makes this system desirable to use in arid areas.

scholarly journals Two-Stage Evaporative Inlet Air Gas Turbine Cooling

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1382
Author(s):  
Obida Zeitoun
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Evaporative Cooling ◽  
Air Cooling ◽  
Vapor Compression ◽  
Two Stage ◽  
Turbine Cooling ◽  
Riyadh City ◽  
Vapor Compression Refrigeration ◽  
Gas Turbine Cooling

Gas turbine inlet air-cooling (TIAC) is an established technology for augmenting gas turbine output and efficiency, especially in hot regions. TIAC using evaporative cooling is suitable for hot, dry regions; however, the cooling is limited by the ambient wet-bulb temperature. This study investigates two-stage evaporative TIAC under the harsh weather of Riyadh city. The two-stage evaporative TIAC system consists of indirect and direct evaporative stages. In the indirect stage, air is precooled using water cooled in a cooling tower. In the direct stage, adiabatic saturation cools the air. This investigation was conducted for the GE 7001EA gas turbine model. Thermoflex software was used to simulate the GE 7001EA gas turbine using different TIAC systems including evaporative, two-stage evaporative, hybrid absorption refrigeration evaporative and hybrid vapor-compression refrigeration evaporative cooling systems. Comparisons of different performance parameters of gas turbines were conducted. The added annual profit and payback period were estimated for different TIAC systems.

Relative Cooling With Liquid for Gas Turbines: Part I — A Solution for Exceeding 2000 K at Turbine Inlet

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Cooling Methods ◽  
Current Operating

Abstract The thermal efficiency of gas turbines is critically dependent on the 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 that exceed 1300 K. Therefore, for this temperature, the thermal efficiency of turbine engine is 40% less than theoretical maximum. Conventional air-cooling techniques of turbine blades allow inlet temperatures of about 1500 K on current operating engines yielding thermal efficiency gains of about 6%. New designs, that incorporate advanced air-cooling methods allows inlet temperatures of 1750–1800 K, with a thermal efficiency gain of about 6% relative to current operating engines. This temperature is near the limit allowed by air-cooling systems. Turbine blades can be cooled with air taken from the compressor or with liquid. Cooling systems with air are easier to design but have a relatively low heat transfer capacity and reduce the efficiency of the engine. Some cooling systems with liquid rely on thermal gradients to promote re-circulation from the tip to the root of turbine blades. In this case, the flow and cooling of liquid are restricted. For best results, cooling systems with liquid should use a pump to re-circulate the coolant. In the past, designers tried to place this pump on the engine stator and therefore were unable to avoid high coolant losses because it is impossible to reliably seal the stator-rotor interface. Therefore it was assumed that cooling systems with liquid could not incorporate pumps. This is an unwarranted assumption as shown studying the system in a moving frame of reference that is linked to the rotor. Here is the crucial fact overlooked by previous designers. The relative motion of engine stator with respect to the rotor is sufficient to motivate a cooling pump. Both the pump and heat exchange system that is required to provide rapid cooling of liquid with cold ambient air, could be located within the rotor. Therefore, the entire cooling system can be encapsulated within the rotor and the sealing problem is circumvented. Compared to recent designs that use advanced air-cooling methods, such a liquid cooling system would increase the thermal efficiency by 8%–11% because the temperatures at turbine inlet can reach stoichiometric levels and most of the heat extracted from turbine during cooling is recuperated. The appreciated high reliability of the system will permit a large applicability in aerospace propulsion.

Turbine Cooling Systems Design: Past, Present and Future

2009 ◽  
Author(s):  
James P. Downs ◽  
Kenneth K. Landis
Keyword(s):  
Research And Development ◽  
Film Cooling ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Systems Design ◽  
Maximum Temperature ◽  
Cooling Systems ◽  
Cooling Flows ◽  
Turbine Cooling

Over a half a century ago, the power and performance of the first gas turbine engines were constrained by material limits on operating temperature. In these machines, the combustor exit temperature could not exceed the capability of the materials used to construct the turbine. Eventually, cooling was introduced into turbine components to enable turbine power and efficiency to be increased. That revolutionary step enabled gas turbines to become competitive with other heat engines for business, particularly in the rapidly expanding aviation and electrical power generation sectors. Although the first cooled turbine components may be considered crude by present standards, the underlying foundation of internal convection cooling remains the backbone for cooled turbine components today. Since its introduction, many improvements and additions to the fundamental basis of turbine component cooling have been developed. The introduction of film cooling is a prominent example. With this past research and development, turbine cooling system designs have progressed to the point where they represent the norm, rather than the exception in today’s gas turbines. Further, the confidence and robustness of these systems has been elevated to the point where the working fluid temperatures can exceed the maximum temperature of the structural materials by wide margins. In this paper, from an engineering perspective, we explore some of the significant accomplishments that have led to the current state-of-the-art in turbine cooling systems design. These systems employ a delicate balance of structural material capabilities with advanced internal and film cooling and the use of thermal barrier coatings to satisfy the goals and objectives of specific applications. At the same time, it is widely recognized that the use of cooling flows in the turbine results in parasitic losses that reduce performance. To that end, we also consider some of the specific challenges that face cooling system designers to reduce cooling flows today. Based on the research and development that has been performed to date, we consider the current status of cooling technology relative to a theoretical peak. Finally, we explore some of the hurdles that must be overcome to effectively raise the bar and realize future advancement of the state-of-the-art. The goal is to measure and separate new technologies that are merely different from those that are superior to past designs. Clearly, the identification of risk and risk reduction will play an important role in the development of future turbine cooling systems.

scholarly journals Innovative Turbine Intake Air Cooling Systems and Their Rational Designing

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6201
Author(s):  
Andrii Radchenko ◽  
Eugeniy Trushliakov ◽  
Krzysztof Kosowski ◽  
Dariusz Mikielewicz ◽  
Mykola Radchenko
Keyword(s):  
Gas Turbines ◽  
Maximum Rate ◽  
Cooling System ◽  
Ambient Air ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Thermal Loads ◽  
Cooling Systems ◽  
Air Cooling System

The efficiency of cooling ambient air at the inlet of gas turbines in temperate climatic conditions was analyzed and reserves for its enhancing through deep cooling were revealed. A method of logical analysis of the actual operation efficiency of turbine intake air cooling systems in real varying environment, supplemented by the simplest numerical simulation was used to synthesize new solutions. As a result, a novel trend in engine intake air cooling to 7 or 10 °C in temperate climatic conditions by two-stage cooling in chillers of combined type, providing an annual fuel saving of practically 50%, surpasses its value gained due to traditional air cooling to about 15 °C in absorption lithium-bromide chiller of a simple cycle, and is proposed. On analyzing the actual efficiency of turbine intake air cooling system, the current changes in thermal loads on the system in response to varying ambient air parameters were taken into account and annual fuel reduction was considered to be a primary criterion, as an example. The improved methodology of the engine intake air cooling system designing based on the annual effect due to cooling was developed. It involves determining the optimal value of cooling capacity, providing the minimum system sizes at maximum rate of annual effect increment, and its rational value, providing a close to maximum annual effect without system oversizing at the second maximum rate of annual effect increment within the range beyond the first maximum rate. The rational value of design cooling capacity provides practically the maximum annual fuel saving but with the sizes of cooling systems reduced by 15 to 20% due to the correspondingly reduced design cooling capacity of the systems as compared with their values defined by traditional designing focused to cover current peaked short-term thermal loads. The optimal value of cooling capacity providing the minimum sizes of cooling system is very reasonable for applying the energy saving technologies, for instance, based on the thermal storage with accumulating excessive (not consumed) cooling capacities at lowered current thermal loads to cover the peak loads. The application of developed methodology enables revealing the thermal potential for enhancing the efficiency of any combustion engine (gas turbines and engines, internal combustion engines, etc.).

Systematic Assessment of Combustion Turbine Inlet Air-Cooling Techniques

2005 ◽  
Vol 127 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Abdalla M. Al-Amiri ◽  
Montaser M. Zamzam
Keyword(s):  
Air Temperature ◽  
Evaporative Cooling ◽  
Heat Rate ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Air Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Wide Range ◽  
The Impact

The current study is centered on assessing the benefits of incorporating combustion turbine inlet air-cooling systems into a reference combustion turbine plant, which is based on a simple cycle under base load mode. Actual climatic conditions of a selected site were examined thoroughly to identify the different governing weather patterns. The main performance characteristics of both refrigerative and evaporative cooling systems were explored by examining the effect of several parameters including inlet air temperature, airflow-to-turbine output ratio, coefficient of performance (for refrigerative cooling systems), and evaporative degree hours (for evaporative cooling systems). The impact of these parameters was presented against the annual gross energy increase, average heat rate reduction, cooling load requirements and net power increase. Finally, a feasibility design chart was constructed to outline the economic returns of employing a refrigerative cooling unit against different prescribed inlet air temperature values using a wide range of combustion turbine mass flow rates.

Thermodynamic Analysis of Air-Cooled Gas Turbine Plants

2000 ◽  
Vol 123 (2) ◽  
pp. 265-270 ◽  
Author(s):  
E. A. Khodak ◽  
G. A. Romakhova
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Direct Determination ◽  
Thermodynamic System ◽  
Flow Diagram ◽  
Air Cooling ◽  
Open Steam ◽  
Turbine Plant ◽  
Turbine Cooling ◽  
Gas Turbine Plant

At present high temperature, internally cooled gas turbines form the basis for the development of highly efficient plants for utility and industrial markets. Minimizing irreversibility of processes in all components of a gas turbine plant leads to greater plant efficiency. Turbine cooling, like all real processes, is an irreversible process and results in lost opportunity for producing work. Traditional tools based on the first and second laws of thermodynamics enable performance parameters of a plant to be evaluated, but they give no way of separating the losses due to cooling from the overall losses. This limitation arises from the fact that the two processes, expansion and cooling, go on simultaneously in the turbine. Part of the cooling losses are conventionally attributed to the turbine losses. This study was intended for the direct determination of lost work due to cooling. To this end, a cooled gas turbine plant has been treated as a work-producing thermodynamic system consisting of two systems that exchange heat with one another. The concepts of availability and exergy have been used in the analysis of such a system. The proposed approach is applicable to gas turbines with various types of cooling: open-air, closed-steam, and open-steam cooling. The open-air cooling technology has found the most wide application in current gas turbines. Using this type of cooling as an example, the potential of the developed method is shown. Losses and destructions of exergy in the conversion of the fuel exergy into work are illustrated by the exergy flow diagram.

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%.

Relative Cooling System: Design and Efficiency

2003 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Thermal Efficiency ◽  
Gas Turbines ◽  
First Generation ◽  
Cooling System ◽  
High Reliability ◽  
Weight Ratio ◽  
Difficult Problem ◽  
Air Cooling ◽  
Cooling Systems ◽  
Aerospace Applications

Cooling systems with liquid for gas turbines that use the relative motion of engine stator with respect to rotor have been called relative cooling systems. This motion actuates the pump for liquid recirculation and the system is 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 systems could be manufactured using existing technologies and would boost thermal efficiency of gas turbines by more than 3% compared to the most advanced air-cooling engines. In the end, relative systems would boost temperatures at turbine inlet to stoichiometric levels and therefore increase thermal efficiency of gas turbines by about 8%. Such systems would recover most heat extracted from turbine for cooling and increase the power to size and power to weight ratio of all gas turbines. The appreciated high reliability of this cooling relies on encapsulation within the rotor and will allow widespread use in both ground and aerospace applications.

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