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gas-turbines
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Axial Turbine Performance Improvement Under Steam Injection
,
M.Sc. Thesis
Sharif University of Technology
;
Ghorbanian, Kaveh
(Supervisor)
Abstract
Steam Injection is one of the most effective methods to improve performance and emission reduction of a gas turbine engine. In this study, the effect of using steam injection on the performance of a mechanical drive gas turbine engine is simulated and power output, thermal efficiency, compressor surge margin, velocity field in axial turbine and turbine isentropic efficiency are examined. In the two-shaft configuration, turbine inlet temperature and gas generator spool speed are the two parameters limiting the output power. On the other hand, matching of compressor turbine and power turbine is an important task that affects the performance of engine under steam injection condition. Based on...
Optimal Design of Induction MHD Generator for Electrical Power Generation from Exhaust of the Gas Turbine Power Plants
, M.Sc. Thesis Sharif University of Technology ; Boroushaki, Mehrdad (Supervisor)
Abstract
Today, due to increasing electricity consumption and demand, the use of conventional systems such as thermal, hydro and nuclear power plants is not enough to convert energy. Over the past century, scientists have sought to discover new technologies for exploiting different forms of energy and converting them into high-efficiency electrical energy. One of these ways is to use the phenomenon of magnetohydrodynamics (magnetic fluid dynamics) to convert thermal energy directly into electrical energy. Magnetohydrodynamics is a theoretical field that studies the dynamics of fluids with electrical conductivity. Induction magneto-hydrodynamic generators use ionized hot plasma (a quasi-neutral gas of...
Gas Turbine Simulator Design for Dynamic Modeling
, M.Sc. Thesis Sharif University of Technology ;
Abstract
In order to observe natural gas turbine phenomena and predicting engine behavior, we need to have a comprehensive simulator in every engine phase of design and analysis. Because of the high cost of manufacturing and prototype experimental tests, it's beneficial to access a gas turbine engine simulator. As well it's hard to make change in a manufactured engine, while we can change a simulator easily.Gas turbine is simulating in zero, one, two and three dimensions. In this project, we have studied previous researches and according to problem, among all simulations, we have studied the ATEC simulation and its assumptions in this thesis. Of these, zero and one dimensional simulations are simpler...
Sustainability Assessment Framework of Co-generation Systems in Tile Industries (Wet route)
, M.Sc. Thesis Sharif University of Technology ; Houshmand, Mahmoud (Supervisor) ; Fatahi Valilai, Omid (Co-Supervisor)
Abstract
There is a growing potential for the use of micro-cogeneration systems in the residential sector because they have the ability to produce both useful thermal energy and electricity from a single source of fuel such as oil or natural gas. Benefits of cogeneration system will cover around 25% of internal electricity needs of ceramic, around 30 % saving in global fuel consumption, reduction of carbon dioxide. In tile factories, there is a system called a spray dryer. This system can use hot air to produce the soil needed to produce ceramic tiles. This hot air is supplied by a very large burner. In developed countries, instead of a burner, a gas turbine is used to produce hot air, with the...
Numerical Investigation of Fuid Injection Effects on Improving the Stability of Centrifugal Compressors
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor)
Abstract
Increasing the surge margin of compressors and preventing surge and stall phenomena have always been one of the main concerns of gas turbine engines. This research aims to numerically investigate the fluid injection effects on the surge margin in centrifugal compressors. In this regard, the NASA CC3 compressor is selected for validation purposes. Considering the available geometrical data, a simulation is performed by using Ansys software, and results are compared with those available from public literature.After the performance and accuracy of the fluid injection simulation results are validated, fluid injection is implemented in the newly selected location and its impact on the compressor...
Experimental & numerical investigation of losses in centrifugal compressor components
, Article Proceedings of the ASME Turbo Expo, San Antonio, Tx ; Volume 6 C , 2013 ; ISBN: 9780791855249 ; Hajilouybenisi, A ; Mojaddam, M ; Sharif University of Technology
2013
Abstract
In this research an analytical model for performance prediction of centrifugal compressors is developed. The loss mechanisms are investigated in impeller, diffuser and volute separately for wide operating rotational speeds of the compressor. The contributions of compressor components in total entropy generation are further studied using different experimental correlations and methods. The results are verified using experimental test results, carried out at Sharif University of technology Turbocharger laboratory which has been designed to derive performance curves of turbocharger compressors. The test rig is equipped to measure static and stagnation pressures at inlet and outlet of each...
Experimental characterization of response of lean premixed low-swirl flames to acoustic excitations
, Article International Journal of Spray and Combustion Dynamics ; Volume 5, Issue 4 , 2013 , Pages 309-328 ; 17568277 (ISSN) ; Shahsavari, M ; Farshchi, M ; Sharif University of Technology
2013
Abstract
Acoustically excited lean premixed low-swirl flames were experimentally investigated to gain a better understanding of detrimental thermoacoustic couplings which can occur in applications like low-NOx gas turbines. Propane-air flames were imaged and analyzed at equivalence ratios of 0.6 to 0.8, mean flow velocities of 3.5 to 5.5 m/s and excitation frequencies of 135 Hz to 555 Hz. It was observed that with increasing excitation frequency, mean flame shape gradually became wider up to a Strouhal number of about 2.5 and then slowly reverted back to the unexcited flame shape. Such large changes in mean flame shape and possibly flow field under acoustic excitations can significantly affect flame...
A novel approach to design reversible counter rotating propeller fans
, Article ASME 2012 Gas Turbine India Conference, GTINDIA 2012, 1 December 2012 through 1 December 2012 ; December , 2012 , Pages 265-270 ; 9780791845165 (ISBN) ; Parizi, P. N ; Taheri, R ; Sharif University of Technology
2012
Abstract
Because of their high performance and unique abilities like producing none-rotating wake, Counter Rotating Propellers (C.R.P.) are being used in many advanced propulsion or ventilation systems. But due to complicated design procedure of C.R.P. fans up to now it was not possible to apply the concept in reversible systems. For the first time in this research, a new method presented to design a reversible counter rotating propeller system. This method is based on designing a basic C.R.P. by a reliable edition of blade element theory to achieve maximum performance in main rotating course and then to optimize it in order to have almost same performance in reverse rotating course. After expressing...
A numerical investigation on effects of the gap between plates of Savonius vertical axis wind turbines with different shapes on their performance
, Article ASME 2012 Gas Turbine India Conference, GTINDIA 2012, 1 December 2012 through 1 December 2012 ; December , 2012 , Pages 259-264 ; 9780791845165 (ISBN) ; Doroodian, F ; Sharif University of Technology
2012
Abstract
Present study introduces the vertical gap between the blades of a Savonius rotor's blades as a parameter that can enhance performance of the rotor. To provide comprehensive concept about application of gap between blades, two different models were tested in different working conditions and working regimes. The study completed by using R.S.M. turbulence model through ANSYS Fluent commercial software package. Utilization of the method was validated by comparing results of a conventional model with experimental data from one of the references. Results of the study proved that application of a proper gap between blades can improve rotor's moment coefficient by 20 percent; however, the amount of...
Numerical study of soot nano-aerosol formation in a JP combustor embedded with a mini-scale air-distributor
, Article 23rd AIAA Computational Fluid Dynamics Conference, 2017, 5 June 2017 through 9 June 2017 ; 2017 ; 9781624105067 (ISBN) ; Ghafourizadeh, M ; Saidi, M. H ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2017
Abstract
The main objective of this work is to investigate the effects of using a miniature or mini-scale air-distributor on the formation of soot nano-particles in a gas turbine combustor burning the jet propellant JP. To evaluate the achieved numerical predictions, it is necessary to choose a test case with available experimental data. It helps to compare the predicted flame structure with that of measurement. After the validation step, the chosen combustor configuration is modified to an inverse non-premixed flame configuration. This helps to split the incoming air between the primary and secondary air streams and to inject the primary air into the inverse flame via a primary air injector....
Model-based fuzzy control of a gas turbine coupled with a dynamometer
, Article Journal of Propulsion and Power ; Volume 34, Issue 5 , 2018 , Pages 1178-1188 ; 07484658 (ISSN) ; Abdollahi Gol, H ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2018
Abstract
This paper discusses a novel and detailed approach for dynamic modeling and control design of a coupled hydraulic dynamometer/turbine-engine system. This study presents a comprehensive model to reveal the coupling effects and an adaptive multiobjective controller to ensure a safe and reliable operation. A fuzzy-based strategy is employed to dynamically adjust the controller gains to keep the state variables and power loading within the desirable operational limits. This approach uses the dynamometer inlet, outlet, and trim valves as well as the turbine fuel flow rate and bleed valve in order to control the system performance during the engine testing process. The proposed fuzzy control...
Experimental and computational investigation into the use of co-flow fluidic thrust vectoring on a small gas turbine
, Article Aeronautical Journal ; Volume 112, Issue 1127 , 2008 , Pages 17-25 ; 00019240 (ISSN) ; Saghafi, F ; Ghoreyshi, M ; Pilidis, P ; Sharif University of Technology
Royal Aeronautical Society
2008
Abstract
This paper presents the application of a relatively new technique of fluidic thrust-vectoring (FTV), named Co-flow, for a small gas-turbines. The performance is obtained via experiment and computational fluid dynamics (CFD). The effects of a few selected parameters including the engine throttle setting, the secondary air mass-flow rate and the secondary slot height upon thrust-vectoring performance are provided. Thrust vectoring performance is characterised by the ability of the system to deflect the engine thrust with respect to the delivered secondary air mass-flow rate. The experimental study was conducted under static conditions in an outdoor environment at Cranfield University workshop...
Improvement of grain structure and mechanical properties of a land based gas turbine blade directionally solidified with liquid metal cooling process
, Article Materials Science and Technology ; Volume 24, Issue 1 , 2008 , Pages 100-106 ; 02670836 (ISSN) ; Mehrara, M ; Varahram, N ; Davami, P ; Sharif University of Technology
2008
Abstract
The manufacturing process of a directionally solidified (DS) IN738LC turbine blade, produced with the liquid metal cooling (LMC) process was improved based on process modelling. The improvement involved varying the system dimensions in the baffle area and optimising the mould thickness, design and the withdrawal parameters. The grain structure of the DS blades produced exhibits a well defined <001> texture with a few stray grains near the blade top compared to the previous design. Some blades were given to a two stage heat treatment followed by tension tests at 25 and 650°C as well as creep tests at 152 MPa/982°C and 340 MPa/850°C. The yield and tensile strength of improved DS blades were...
Performance evaluation of a gas turbine operating noncontinuously with its inlet air cooled through an aquifer thermal energy storage
, Article Journal of Energy Resources Technology, Transactions of the ASME ; Volume 129, Issue 2 , 2007 , Pages 117-124 ; 01950738 (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2007
Abstract
The power output of gas turbines (GT) reduces greatly with the increase of the inlet air temperature. This is a serious problem because gas turbines have been used traditionally to provide electricity during the peak power demands, and the peak power demands in many areas occur on summer afternoons. An aquifer thermal energy storage (ATES) was employed for cooling of the inlet air of the GT. Water from a confined aquifer was cooled in winter and was injected back into the aquifer. The stored chilled water was withdrawn in summer to cool the GT inlet air. The heated water was then injected back into the aquifer. A 20 MW GT power plant with 6 and 12 h of operation per day, along with a...
Energy and exergy analysis of internal reforming solid oxide fuel cell-gas turbine hybrid system
, Article International Journal of Hydrogen Energy ; Volume 32, Issue 17 , December , 2007 , Pages 4591-4599 ; 03603199 (ISSN) ; Sharif University of Technology
2007
Abstract
The aim of this work is to analyze methane-fed internal reforming solid oxide fuel cell-gas turbine (IRSOFC-GT) power generation system based on the first and second law of thermodynamics. Exergy analysis is used to indicate the thermodynamic losses in each unit and to assess the work potentials of the streams of matter and of heat interactions. The system consists of a prereformer, a SOFC stack, a combustor, a turbine, a fuel compressor and air compressor, recuperators and a heat recovery steam generator (HRSG). A parametric study is also performed to evaluate the effect of various parameters such as fuel flow rate, air flow rate, temperature and pressure on system performance. © 2007...
Multi-directional co-flow fluidic thrust vectoring intended for a small gas turbine
, Article 2007 AIAA InfoTech at Aerospace Conference, Rohnert Park, CA, 7 May 2007 through 10 May 2007 ; Volume 3 , 2007 , Pages 2278-2286 ; 1563478935 (ISBN); 9781563478932 (ISBN) ; Saghafi, F ; Ghoreyshi, M ; Pilidis, P ; Sharif University of Technology
2007
Abstract
This paper concerns an understanding of thrust vectoring, in the presence of co-flowing secondary air. An experimental and computational study was performed on a circular-shape nozzle, integrated with a Coanda surface, to investigate the feasibility of multi-directional deflection of the engine exhaust gases. The vectoring angle was controlled by the relative blowing momentum of air that was injected tangentially through the slots, surrounding the main nozzle. A state of the art design that uses a small step, just after the main nozzle to turn the flow into eddy, was also employed to enhance the effectiveness of the method. The secondary section was divided into four identical sections for...
Failure analysis of a gas turbine marriage bolt
, Article Journal of Failure Analysis and Prevention ; Volume 7, Issue 2 , 2007 , Pages 81-86 ; 15477029 (ISSN) ; Salimi, H. R ; Sharif University of Technology
2007
Abstract
A gas turbine which output 18MW power exploded after 3h of ordinary operation and after 4,785 starts. The turbine's rotor had undergone repair after 77,000 operating hours. A piece was cut from the failed marriage bolt and tested using atomic absorption spectrometry in order to know the grade of the alloy. It was found that the marriage bolt is made from ASTM A193 B16 steel which is suitable. Hardness and microhardness measurement was also determined and showed that it was within the range of the specified hardness for ASTM A193 B16 steel. The marriage bolt's mechanical properties also meet technical specifications and showed that it contained anti-corrosion properties. Visual examination...
Comparative evaluation of advanced gas turbine cycles with modified blade cooling models
, Article 2006 ASME 51st Turbo Expo, Barcelona, 6 May 2006 through 11 May 2006 ; Volume 4 , 2006 , Pages 537-546 ; 0791842398 (ISBN); 9780791842393 (ISBN) ; Khaledi, H ; Hajilouy Benisi, A ; Sharif University of Technology
2006
Abstract
Advanced gas turbine cycles use advanced blade cooling technologies to reach high turbine inlet temperature. Accurate modeling and optimization of these cycles depend on blade cooling model. In this study, different models have been used to simulate gas turbine performance. The first model is the continuous model and the second is stage-by-stage model with alternative methods for calculating coolant, stagnation pressure loss and SPR. Variation of specific heat and enthalpy with temperature are included in both models. The composition of gas stream in turbine is changed step by step due to air cooling. These models are validated by two case study gas turbine results, which show good agreement...
Modeling of gas turbine combustor using dynamic neural network
, Article 2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006, Chicago, IL, 5 November 2006 through 10 November 2006 ; 2006 ; 10716947 (ISSN); 0791837904 (ISBN); 9780791837900 (ISBN) ; Mozafari, A. A ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2006
Abstract
This paper presents an Artificial Neural Network (ANN) - based modeling technique for prediction of outlet temperature, pressure and mass flow rate of gas turbine combustor. ANN technique has been developed and used to model temperature, pressure and mass flow rate as a nonlinear function of fuel flow rate to the combustion chamber. Results obtained by present modeling are compared with those obtained by experiment. A quantitative analysis of modeling technique has been carried out using different evaluation indices; namely, Mean-Square-Quantization-Error (MSQE) and actual percentage error. The results show the effectiveness and capability of the proposed modeling technique with reasonable...
Parameters affecting turbulent film cooling reynolds-averaged navier-stokes computational simulation
, Article Journal of Thermophysics and Heat Transfer ; Volume 20, Issue 1 , 2006 , Pages 92-100 ; 08878722 (ISSN) ; Taeibi Rahni, M ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2006
Abstract
Film cooling of surfaces appears in many applications. For instance, it is one of the most effective methods to improve the efficiency of gas turbines. As a fundamental study, two different types of film cooling (slot and discrete holes injections) are numerically simulated here. A flat surface is used to model a small portion of a gas turbine blade. Incompressible, stationary, viscous, turbulent flow is assumed using the STAR-CD software with the standard k-ε model and a cell-centered finite volume method on a nonuniform structured grid. The jet flow Reynolds number, based on the jet's hydraulic diameter, is 4.7 × 103. The study of the injection angle and the velocity ratio shows that the...