A Generalized Mathematical Model to Estimate Gas Turbine Starting Characteristics

1982 ◽  
Vol 104 (1) ◽  
pp. 194-201 ◽  
Author(s):  
R. K. Agrawal ◽  
M. Yunis
Keyword(s):  
Mathematical Model ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
System Combination ◽  
Turbine Performance ◽  
Start Up ◽  
Starting Characteristics ◽  
Starting Torque

The paper describes a generalized mathematical model to estimate gas turbine performance in the starting regime of the engine. These estimates are then used to calculate the minimum engine starting torque requirements, thereby defining the specifications for the aircraft starting system. Alternatively, the model can also be used to estimate the start up time at any ambient temperature or altitude for a given engine/aircraft starting system combination.

scholarly journals A Generalized Mathematical Model to Estimate Gas Turbine Starting Characteristics

1981 ◽  
Author(s):  
R. K. Agrawal ◽  
M. Yunis
Keyword(s):  
Mathematical Model ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
System Combination ◽  
Turbine Performance ◽  
Start Up ◽  
Starting Characteristics ◽  
Starting Torque

The paper describes a generalized mathematical model to estimate gas turbine performance in the starting regime of the engine. These estimates are then used to calculate the minimum engine starting torque requirements, thereby defining the specifications for the aircraft starting system. Alternatively, the model can also be used to estimate the start up time at any ambient temperature or altitude for a given engine/aircraft starting system combination.

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.

Investigation of a Nonlinear Numerical Mathematical Model of a Multi-Shaft Gas Turbine Unit

2003 ◽  
Author(s):  
Soo Yong Kim ◽  
Valeri P. Kovalevsky
Keyword(s):  
Mathematical Model ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Ambient Air ◽  
Static Characteristic ◽  
Start Up ◽  
Static Calculation ◽  
Energy Balances ◽  
The Mathematical Model ◽  
Mass And Energy Balances

The development of numerical mathematical model to calculate both the static and dynamic characteristics of a multishaft gas turbine consisting of a single combustion chamber, including advanced cycle components such as intercooler and regenerator is presented in the paper. The mathematical model is based on the simplified assumptions that quasi-static characteristic of a turbo-machine and injector is used, total pressure loss and heat transfer relation for static calculation neglecting fuel transport time delay can be employed. The supercharger power has a cubical relation to its rotating velocity. The accuracy of each calculation is confirmed by monitoring mass and energy balances, and comparative calculations with different time steps of integration. The features of the studied gas turbine scheme are the starting device with compressed air bottles and injector supercharging air directly ahead of the combustion chamber. The start-up algorithms are reviewed at different geometrical characteristics of the injector and temperatures of ambient air.

scholarly journals Modeling and Control of the Starter Motor and Start-Up Phase for Gas Turbines

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 363
Author(s):  
Soheil Jafari ◽  
Seyed Miran Fashandi ◽  
Theoklis Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Numerical Solutions ◽  
Frequency Converter ◽  
Variable Structure ◽  
Transient Behavior ◽  
Intermediate Stage ◽  
Mechatronic System ◽  
Turbine Performance ◽  
Start Up

Improving the performance of industrial gas turbines has always been at the focus of attention of researchers and manufacturers. Nowadays, the operating environment of gas turbines has been transformed significantly respect to the very fast growth of renewable electricity generation where gas turbines should provide a safe, reliable, fast, and flexible transient operation to support their renewable partners. So, having a reliable tools to predict the transient behavior of the gas turbine is becoming more and more important. Regarding the response time and flexibility, improving the turbine performance during the start-up phase is an important issue that should be taken into account by the turbine manufacturers. To analyze the turbine performance during the start-up phase and to implement novel ideas so as to improve its performance, modeling, and simulation of an industrial gas turbine during cold start-up phase is investigated this article using an integrated modular approach. During this phase, a complex mechatronic system comprised of an asynchronous AC motor (electric starter), static frequency converter drive, and gas turbine exists. The start-up phase happens in this manner: first, the clutch transfers the torque generated by the electric starter to the gas turbine so that the turbine reaches a specific speed (cranking stage). Next, the turbine spends some time at this speed (purging stage), after which the turbine speed decreases, sparking stage begins, and the turbine enters the warm start-up phase. It is, however, possible that the start-up process fails at an intermediate stage. Such unsuccessful start-ups can be caused by turbine vibrations, the increase in the gradients of exhaust gases, or issues with fuel spray nozzles. If, for any reason, the turbine cannot reach the self-sustained speed and the speed falls below a certain threshold, the clutch engages once again with the turbine shaft and the start-up process is repeated. Consequently, when modeling the start-up phase, we face discontinuities in performance and a system with variable structure owing to the existence of clutch. Modeling the start-up phase, which happens to exist in many different fields including electric and mechanical application, brings about problems in numerical solutions (such as algebraic loop). Accordingly, this study attempts to benefit from the bond graph approach (as a powerful physical modeling approach) to model such a mechatronic system. The results confirm the effectiveness of the proposed approach in detailed performance prediction of the gas turbine in start-up phase.

Gas Turbine Fogging Technology: A State-of-the-Art Review—Part I: Inlet Evaporative Fogging—Analytical and Experimental Aspects

2006 ◽  
Vol 129 (2) ◽  
pp. 443-453 ◽  
Author(s):  
R. K. Bhargava ◽  
C. B. Meher-Homji ◽  
M. A. Chaker ◽  
M. Bianchi ◽  
F. Melino ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Gas Turbine ◽  
State Of The Art ◽  
Operating Cost ◽  
Heat Rate ◽  
Cost Effective ◽  
Power Demand ◽  
Factors Affecting ◽  
Turbine Performance ◽  
Experimental Findings

Ambient temperature strongly influences gas turbine power output causing a reduction of around 0.50% to 0.90% for every 1°C of temperature rise. There is also a significant increase in the gas turbine heat rate as the ambient temperature rises, resulting in an increased operating cost. As the increase in power demand is usually coincident with high ambient temperature, power augmentation during the hot part of the day becomes important for independent power producers, cogenerators, and electric utilities. Evaporative and overspray fogging are simple, proven, and cost effective approaches for recovering lost gas turbine performance. A comprehensive review of the current understanding of the analytical, experimental, and practical aspects including climatic and psychrometric aspects of high-pressure inlet evaporative fogging technology is provided. A discussion of analytical and experimental results relating to droplets dynamics, factors affecting droplets size, and inlet duct configuration effects on inlet evaporative fogging is covered in this paper. Characteristics of commonly used fogging nozzles are also described and experimental findings presented.

Analysis of Singas FED Gas Turbine Performance Depending on Ambient Conditions

2003 ◽  
Author(s):  
S. Brusca ◽  
R. Lanzafame
Keyword(s):  
Mathematical Model ◽  
Relative Humidity ◽  
Gas Turbine ◽  
Engine Performance ◽  
Maximum Relative Error ◽  
Ambient Conditions ◽  
Turbine Performance ◽  
Air Temperatures ◽  
Performance Reduction ◽  
Relative Errors

It is well known that gas turbine performance is quite influenced by ambient conditions such as pressure, air temperature and relative humidity. This paper deals with the effects of ambient conditions on performance of gas turbine fired with syngas. A mathematical model of the engine has been implemented within GateCycle workspace and using experimental data, it has been finely tuned and tested. Results analysis showed that it is able to simulate engine running in on–design and off–design conditions (maximum relative error is about 1%). Thus, gas turbine running simulations depending on ambient temperature and relative humidity have been carried out. Results analysis showed that at high air temperatures (higher then the one corresponding to maximum IGV opening) performance reduction occur. On the contrary, high values of relative humidity allow to reduce power losses in the same temperature range. In conclusion, the developed mathematical model is able to simulate gas turbine running with low relative errors. So that, it could be used in order to optimise engine performance at the ambient conditions that occur for the site of the IGCC Complex in which gas turbine is integrated.

A Simple Sub-Idle Component Map Extrapolation Method

2007 ◽  
Author(s):  
Shaun R. Gaudet ◽  
J. E. Donald Gauthier
Keyword(s):  
Gas Turbine ◽  
Extrapolation Method ◽  
Test Case ◽  
Performance Models ◽  
Idle Speed ◽  
Turbine Performance ◽  
Lack Of Information ◽  
Start Up ◽  
Map Data ◽  
Component Map

This paper describes a simple sub-idle component map extrapolation method. Used in conjunction with gas turbine performance models, it enables designers to estimate sub-idle gas turbine performance during engine start-up. The lack of information available regarding component maps in the sub-idle regime creates major challenges for starting system designers or control system designers as the numerical convergence of performance models decreases rapidly below idle speed. The proposed component map extrapolation method alleviates this problem by extrapolating given component map data well below idle speed. The underlying equations of the method are based on the principles of incompressible similarity laws. Also known as pump laws, these equations are modified to account for compressibility effects by varying the similarity law exponents. To estimate the integrity of the extrapolated component maps and to build confidence in the sub-idle extrapolation method, extrapolate speed lines were compared to speed lines found in the original component map. Even though the extrapolation method is yet to be experimentally validated, preliminary estimates showed that the extrapolation method did produce adequate component maps. To demonstrate the potential of the component extrapolation method when used in conjunction with gas turbine performance models, a virtual test case engine was modeled and used to produce start-up performance data.

Fogging for Evaporative Cooling Effects on Siemens V94.2 Gas Turbine Performance

2002 ◽  
Author(s):  
S. Brusca ◽  
R. Lanzafame
Keyword(s):  
Relative Humidity ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Control Strategies ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Air Humidity ◽  
Power Losses ◽  
Turbine Performance ◽  
Cooling Effects

In order to study the effects of ambient temperature and relative humidity on the performance of the Siemens V94.2 gas turbine, installed as a topper in an IGCC complex and fed with syngas, a mathematical model of the engine has been developed and implemented into GateCycle environment. The model was fine tuned using experimental data of plant. Thermodynamic analysis of the gas turbine performance, depending on ambient temperature and relative humidity, has been carried out. Results show the strong dependence of engine performance on ambient temperature (in the range from 30 °C to 40 °C). Theoretical and experimental results have been shown that ambient air humidity decreases power losses due to high external temperature. In order to optimize power production in this temperature range, an artificial humidifier was implemented into the model. Furthermore, “Fogging for Evaporative Cooling” technique effects on performance of the gas turbine have been studied. Using GateCycle model, simulations have been carried out as regards to temperature variation in the range which power losses occur. Two control strategies of the artificial air humidifier have been implemented: the first is characterized by an air humidity constant at the intake of the compressor (set to 95%); the second one is characterized by an air temperature constant at the intake of the compressor (set to the temperature corresponding to maximum IGV opening). For both control strategies, power losses recovery can be achieved depending on base air humidity and temperature. Applying the second control strategy, lower water consumption was achieved but a compression ratio very close to the limit value was observed.

Experimental and Analytical Study on the Operation Characteristics of the AHAT System

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hidefumi Araki ◽  
Tomomi Koganezawa ◽  
Chihiro Myouren ◽  
Shinichi Higuchi ◽  
Toru Takahashi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Pilot Plant ◽  
Temperature Effects ◽  
Operational Flexibility ◽  
Start Up ◽  
Air Turbine ◽  
Load Characteristics

Operational flexibility, such as faster start-up time or faster load change rate, and higher thermal efficiency, have become more and more important for recent thermal power systems. The advanced humid air turbine (AHAT) system has been studied to improve operational flexibility and thermal efficiency of the gas turbine power generation system. Advanced humid air turbine is an original system which substitutes the water atomization cooling (WAC) system for the intercooler system of the HAT cycle. A 3 MW pilot plant, which is composed of a gas turbine, a humidification tower, a recuperator and a water recovery system, was built in 2006 to verify feasibility of the AHAT system.In this paper, ambient temperature effects, part-load characteristics and start-up characteristics of the AHAT system were studied both experimentally and analytically. Also, change in heat transfer characteristics of the recuperator of the 3 MW pilot plant was evaluated from Nov. 2006 to Feb. 2010. Ambient temperature effects and part-load characteristics of the 3 MW pilot plant were compared with heat and material balance calculation results. Then, these characteristics of the AHAT and the combined cycle (CC) systems were compared assuming they were composed of mid-sized industrial gas turbines.The measured cold start-up time of the 3 MW AHAT pilot plant was about 60 min, which was dominated by the heat capacities of the plant equipment. The gas turbine was operated a total of 34 times during this period (Nov. 2006 to Feb. 2010), but no interannual changes were observed in pressure drops, temperature effectiveness, and the overall heat transfer coefficient of the recuperator.

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