Turbine inlet temperature strongly affects Gas Turbine Performance. Today blade cooling technologies facilitate the use of higher inlet temperatures. Of course blade cooling causes some thermodynamic penalties that destroys to some extent the positive effect of higher inlet temperatures. This research aims to model and evaluate the Performance of Gas Turbine cycle with air cooled Turbine. In this study internal and transpiration cooling methods has been investigated and the penalties as the result of Gas flow friction, cooling air throttling, mixing of cooling air flow with hot Gas flow, and irreversible heat transfer have been considered. In addition, it is attempted to consider any factor influencing actual conditions of system in the analysis. It is concluded that penalties due to blade cooling decrease as permissible temperature of the blade surface increases. Also it is observed that transpiration method leads to better Performance of Gas Turbine comparing to internal cooling method.

Triple shaft Gas Turbines are the most Gas compressor driven in natural Gas compressor station in national Iranian Gas Company. In the recent study, exergy equilibrium formula of each components of Gas compressor station specified and several mathematical models made. The model predict different parameters based on environmental and operational conditions. Models made by multivariate linear regression and ANOVA technique that made high precision models. The models results show that how varying the environment and operational condition such compressor inlet temperature, Turbine inlet temperature and Turbine pressure ratio affect exergy efficiency, fuel consumption, exergy destruction and specific fuel consumption. In this study effects of environmental and operational variables on this parameters and interaction of this variable on each other surveyed. Results showed that variation in each variables has no effect in slope of net output power variation due to change in other variables, whereas compressor inlet temperature and pressure ratio in exergy efficiency model, Turbine inlet temperature and pressure ratio in fuel consumption model and Turbine and compressor inlet temperature in specific fuel consumption model have interaction on their model's response

This study aims to evaluate the Performance of a simple cycle Gas Turbine power plant by analysing the effect of different operating parameters. These operating parameters include compressor pressure ratio and compressor & Turbine isentropic efficiencies. The study quantitatively assesses the exergetic efficiency and the exergy destruction of each unit in the cycle, as well as the power used or produced by the cycle. Any change in these parameters can significantly impact the power plant's overall Performance through a specific unit in the cycle. For instance, increasing the compressor pressure ratio can reduce the temperature difference across the combustor, lessening the exergy destruction and improving the cycle’s overall Performance. However, any decline in the compressor or the Turbine isentropic efficiency results in an increase in the exergy destruction of the affected unit and can result in a decrease in the overall cycle Performance. This is due to either an increase in power required by the compressor or a decrease in power produced by the Turbine. The analysis suggests that the Turbine isentropic efficiency has a greater impact on the net power generated than the compressor isentropic efficiency. Additionally, the Turbine inlet temperature is a dependent variable as operating at different compressor pressure ratios and compressor isentropic efficiencies lead to varying Turbine inlet temperatures. Therefore, increasing the Turbine inlet temperature does not always lead to improved Performance.

A general mathematical model is developed to specify the Performance of an irreversible Gas Turbine Brayton cycle incorporating two-stage compressor, two-stage Gas Turbine, intercooler, reheater, and regenerator with irreversibilities due to finite heat transfer rates and pressure drops. Ranges of operating parameters resulting in optimum Performance (i.e., hI³38³hII³60%, ECOP³1.65, xloss£0.150 MJ/kg, BWR£0.525, wnet³0.300 MJ/kg, and qadd£0.470 MJ/kg) are determined and discussed using the Monte Carlo method. These operating ranges are minimum cycle temperature ranges between 302 and 315 K, maximum cycle temperature ranges between 1,320 and 1,360 K, maximum cycle pressure ranges between 1.449 and 2.830 MPa, and conductance of the heat exchanger ranges between 20.7 and 29.6 kW/K. Exclusive effect of each of the operating parameters on each of the Performance parameters is mathematically given in a general formulation that is applicable regardless of the values of the rest of the operating parameters and under any condition of operation of the cycle.

Gas Turbines are always intended to give more specific work output for which continuous exposure to hot combustion Gases is necessary. To increase the lifespan of the Turbine blades active cooling should be applied to the High Pressure (HP) Turbine blades. In the present work, a simple open cycle Gas Turbine is modeled to carry out thermodynamic analysis with different open loop steam cooling techniques: steam internal convection cooling (SICC), steam film cooling (SFC) and steam transpiration (STC) cooling. The effect of Turbine inlet temperature (TIT), Turbine blade temperature (Tb), and Compressor pressure ratio (CPR) on the coolant flow requirement and effect of T_b on the Performance were estimated. The entire analysis is carried out with contemplation of variable specific heat (VSH) along with constant specific heats (CSH) for air and Gas. Between VSH and CSH approaches, the former analysis leads to better Performance from the first and second law efficiencies point of view. Irreversibility and Entropy generation rate are maximum in the combustor and they are less for VSH case in all cooling schemes and are decreased by 38. 5 40 and 40. 4% for SICC, SFC and STC schemes, respectively when compared with CSH (at TIT=1580K, Tb=1123K, CPR=19. 1) analysis.

In the present work, the effects of blades number on the Performance of two stages axial Gas Turbine have been investigated numerically. Geometry characteristics of the Gas Turbine have been chosen based on the F5 model of General Electric Company. First, the blades geometry and fluid passages are initially generated due to the real dimensions of the Turbine and the generated geometry is networked. Then, the final model of the Turbine is generated by gridding blades which set beside each other. Then, Ansys CFX software is used to solve the 3D Navier-Stokes equations in the generated computational domain. The shear stress transport turbulence model has been employed in order to determine the wall effects on the turbulent flow. Before any change in the main Turbine, a numerical study was performed and a comparison was conducted between the numerical results and experimental results measured in the power station which the results show a good level of agreement between them. The number of blades of each row has been changed in order to investigate the effects of blade number on the Turbine efficiency. The results show that the power generation of the Turbine and its efficiency are increased by 0. 83% and 0. 81%, respectively by an increase in the number of second-row stator blades from 62 to 71 blades.

Radial inflow Gas Turbines are widely used in diesel engines turbochargers. They increase power and efficiency and reduce SFC in engines. The flow conditions of the turbocharger’s Turbine are highly varying, due to engine exhaust. The knowledge of Turbine behavior in such conditions is a basic requirement for the development of turbocharger to improve engine Performance. In this paper, the Performance of the radial inflow Gas Turbine is investigated experimentally as well as advanced one dimensional modeling. The principal equation of a flow model is the dimensionless mass flow rate equation which combines the equations of continuity, energy and entropy with modeling the losses, under steady state and full admission conditions. In this study mass flow rate, pressure ratio and efficiency are unknown, with known Turbine geometry, inlet and outlet total pressure and temperature of the Turbine, Performance characteristics can be calculated. In one-dimensional modeling the flow passage of radial flow Turbine is divided into several regions such as: inlet duct, volute, incident and rotor, and the flow is modeled in each part separately. The requirement of the analytical procedure is to predict the component discharge conditions from known inlet conditions and component geometry. The computed discharge conditions then become known inlet conditions for the next component. Incident loss at the rotor inlet is the main cause of efficiency drop under off design conditions. In practice the best efficiency occurs at optimum incident angle, so any deviation from optimum incident angle causes extra losses. Incident loss is part of the rotor loss but in this study, due to modeling strategy it is modeled separately. In this study Wallace model have been adopted to calculate the incident loss, which is assumed that for the off design condition the change in deviation of the fluid entry the Turbine rotor takes place at constant pressure. This model is compared with simple NASA model, which shows improving the Turbine calculated Performance results. The complex, three-dimensional flow pattern in the rotor gives raise the difficulties in the rotor modeling and causes the major Turbine losses happening in the rotor. The following losses are used in this section: friction losses, blade loading losses, tip clearance losses and exit velocity losses. Experimental investigation of the research is carried out on special test facility under full admission conditions for a wide range of speed. The efficiency and mass parameter characteristics of the Turbine are obtained from the modeling and are compared with that of experimental results over a wide rang of speeds showing good agreements. The main limitation in experimental data is due to the compressor surge. The maximum difference between experimental and theoretical results under full admission conditions is 5.1% for mass parameter, and 7.2% for efficiency.

This research aims to find suitable measurements to detect the occurrence of Turbine erosion in Micro Gas Turbine engines. For this purpose, the off-design operation of this engine under the Turbine's normal and eroded conditions has been modeled and the behavior of different parameters of the Gas path has been analyzed. Turbine erosion is one of the most popular issues in Gas Turbine Performance degradation. Accordingly, to have proportional health condition monitoring and diagnostics, it is necessary to know the effects of Turbine erosion. Characteristic curves of an eroded Turbine is utilized by the proposed off-design model to find the best parameters to detect Turbine erosion. In the course of this research, two operation scenarios, one with maintaining the output power and the other with maintaining Turbine inlet temperature, are examined. In both scenarios, the running line shifts to a new location with higher airflow and lower pressure ratio. When Turbine inlet temperature is maintained, fuel flow, pressure ratio, and output power fall dramatically (9.8%, 11.1%, and 14.3% respectively) while in the other scenario temperature in the combustion chamber inlet and the Turbine exhaust with 7% and 7.6% rise and pressure ratio with 4.4% reduction show most deviations from the healthy condition. So depending on the control scenario, the proper parameters can be selected from these sensitive parameters to detect Turbine erosion in the Micro Gas Turbine.

Today, Gas Turbines are considered as one of the most important equipment in energy industry and with a lot of applications in other industries. So far, very few CFD studies on the effect of roughness on Turbine Performance have been performed. This paper presents numerical study of roughness which affects Performance of a single stage axial flow Turbine. Numerical calculations have been performed using an in-house developed software in the C++ environment employing Roe scheme to solve governing equations in generalized coordinates. In order to simulate the turbulent flow the Baldwin-Lomax model and for simulating the roughness the Cebeci-Chang model is used. To realize the roughness effects in a Turbine stage, several roughness heights in transitionally rough and fully rough flow regimes on the stator and rotor blades have been simulated. Results show that the efficiency is reduced with increasing roughness height. Also, with increasing the surface roughness of the stator and rotor, deviation angle will increase and thus the work coefficient will reduce. Moreover, the loss coefficient in both stator and rotor blades is increased especially, suction surfaces are faced with more losses.