The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the ''combined cycle''. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above.

The performance of a gas turbine is significantly affected by the environmental conditions. Net power output of a gas turbine can be increased by reducing the compressor inlet air temperature. There are different techniques used for inlet air cooling of the gas turbines. These techniques are evaporative coolers, spray inlet coolers or fogging systems, and mechanical refrigeration or chillers where a heat exchanger cools the inlet air. To improve the efficiency of gas turbine power plants, Ice Thermal Energy Storage (ITES) systems can be used as inlet cooling system.
The aim of this study is to determine the use of an ITES system for a 239 MW powered gas turbine cycle, which is located in Bursa / Turkey. The performance of the system was investigated for full load conditions. Energy and exergy analysis were done by using last decade’s meteorological weather data. The results showed that utilizing the ITES system boosted the net power up to 12.60 %.

A high fidelity real time simulation code based on a lumped, non-linear representation of gas turbine components is presented. The code is a general-purpose simulation software environment useful for setting up and testing control equipments. The mathematical model and the numerical procedure are specially developed in order to efficiently solve the set of algebraic and ordinary differential equations that describe the dynamic behavior of gas turbine engines. For high fidelity purposes, the mathematical model takes into account the actual composition of the working gases and the variation of the specific heats with the temperature, including a stage by stage model of the air-cooled expansion. The paper presents the model and the adopted solver procedure. The code, developed in Matlab Simulink using an object oriented approach, is flexible and can be easily adapted to any kind of plant configuration.
Simulation tests of the transients after load rejection have been carried out for a single-shaft heavy-duty gas turbine and a double-shaft aero derivative industrial engine. Time plots of the main variables that describe the gas turbine dynamic behavior are shown and the results regarding the computational time per time step are discussed.

The climate condition affects the performance of the combined-cycle power plants. The efficiency of the combined
cycle is significantly influenced by the temperature, pressure and humidity of the air. When the ambient air
temperature increases, the density of the air decreases, and it leads to a reduction of power generated by the gas
turbine. In this work, the energy and exergy analysis of a commercial gas turbine, with inlet air cooling, was
performed. The effects of fogging system on gas-turbine performance studied. For this aim, the energy and exergy
balances were obtained for each piece of equipment. Calculations have been made for four different cases for the
regarded gas turbine system. Furthermore, exergetic efficiency, exergy destruction rates and improvement
potentials were obtained, and the results of the study demonstrated graphically. It is concluded that the net power
output of the gas turbine system increased at lower inlet temperatures and exergy destruction rates occurred from
highest to lowest as combustion chamber (CC), gas turbine (GT) and air compressor (AC), respectively.

In this paper energy, exergy and thermoeconomic analysis of a combined cooling, heating and power (CCHP) system has been performed. Applying the first and second laws of thermodynamics and economic analysis, simultaneously, has made a powerful tool for the analysis of energy systems such as CCHP systems.

Based on very early occurring ruptures found in the first stage high pressure turbine blades of a turbo reactor in a local aviation company, this study has the aim to determine their safe life. The first stage blades are subjected to simultaneous action of gas pressure coming from the combustion chamber, centrifugal forces in the case of the rotor blades and to important temperatures transients, which progress in a very aggressive environment due to hot gases. These combined parameters cause a high state of stress involving several complex mechanisms of damage, such as: fatigue caused by mechanical stress fluctuations, thermo-mechanical fatigue caused by temperature variations and corrosion caused on the stressed elements. Life cycle determination asks for stress evaluation of blades regarding several variables which are approached deterministically in the study. Heat exchange between combustion gases and metal blades is considered. The total stress on two kinds of blades is calculated by the addition of the thermal effect and the mechanical loading. The stress cycle is then calculated for different steps of the engine function during the operation by considering the variation of the thermal and the mechanical properties of the system. Safe life determination is done by two different approaches: the safe life approach by the initiation model and the damage tolerance approach considering the defect growth mechanics and considering the pitting corrosion effect. The calculation is applied for stator and rotor blades of an aero engine high pressure turbine made of NI 738. Since these parts are high risk components from the point of view of potential failure consequences, the risk is assessed as well. The results obtained are studied to determine the solution to the problem, and to propose a safe decision to be taken about the design or maintenance procedures.

The purpose of current study is to analyze the performance of an open cycle gas turbine power plant using the concepts of exergoeconomics. Exergoeconomic technique involves the use of Second law of thermodynamics and assigns monetary values to the thermodynamic quantity known as exergy. Analyses based on exergoeconomic criteria are done for the open cycle gas turbine power plant turbine. The methodology is illustrated using the example of a 25 MW open cycle gas turbine power plant. Optimization has been done for the open cycle gas turbine power plant as tradeoffs between the unit product cost of the compressor and combustion chamber as functions of compressor pressure ratio and unit product costs of combustion chamber and gas turbine as functions of turbine inlet temperature.

Biomass has great potential as a clean and renewable feedstock for producing modern energy carriers. This paper focuses on the process of biomass gasification, wherein the synthesis gas is subsequently used to produce electricity. A comparison between the most promising design configurations for the industrial application of gasification based, biomass-to-energy cogenerators in the 100-600 kWe range is presented. Mass and energy balances and material and substance flow analyses drawn for each design solutions are based on the experimental data obtained from a pilot scale bubbling fluidized bed air gasifier, having a feeding capacity of 100 kg/h and operated with a commercially available, natural biomass. Measurements taken during the experimental tests include the syngas complete composition as well as the characterization of the bed material, the entrained fines collected at the cyclone and the purge material from the scrubber. The techno-economic performances of two energy generation devices, a gas engine and an externally-fired gas turbine, have been estimated on the basis of the manufacturer's specifications. The study concludes that the internal combustion engine layout is the solution that currently offers the higher reliability and provides the higher internal rate of return for the investigated range of electrical energy production.

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of applications of PMC so as to enable the researchers to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions.