This thesis covers the development of a simulator for the Siemens Gas Tur-bine SGT-600. An explanation on how a gas turbine works is also given, as well as the principles behind the control system used by Siemens to control the turbine. For Siemens Industrial Turbomachinery to be able to test its control sys-tem before delivering a gas turbine to the customer, a simulator is needed. The control system needs to be adjusted for every unique gas turbine, since there are several options for the customer to choose between when ordering the turbine. A control system standard is under development, which also needs to be tested in a simulator. The framework for the simulator, i.e. the hardware and software that form the simulator system, was predefined to suit this specific purpose. The Siemens software SIMIT is used for developing the model. SIMIT is a real time simulation tool where models are constructed using blocks, similar to MATLAB Simulink. A gas turbine is basically a heat engine that produces mechanical energy or electricity. The main task of the control system is to control the fuel flow to the combustion chamber and by that keeping the machine at desired speed. The gas turbine model was developed using measurement data from a site in Hungary, where a gas turbine of the type SGT-600 is in service. The model is based on simplified relations between the signals. By analyzing measurement data and learning about the functionality of a gas turbine it was found out that the speed of the gas generator affected most other sig-nals, like temperatures and pressures. The gas generator speed was found to be dependent on the heat flow, which is determined by the openings of the gas control valves. As a result of this thesis a working simulator for the gas turbine SGT-600 has been developed. The simulator can be used for testing the control sys-tem standard and for testing the control system when adapting it to a spe-cific delivery. It is also suitable for educational purposes, for example to instruct customers.

A first part of a ”Heat Transfer Handbook” about correlations for internal cooling of gas turbine vanes and blades has been created. The work is based on the cooling of vanes and blades 1 and 2 on different Siemens Gas Turbines. The cooling methods increase the heat transfer in the cooling channels by increasing the heat transfer coefficient and/or increasing the heat transfer surface area. The penalty paid for the increased heat transfer is higher pressure losses. Three cooling methods, called rib turbulated cooling, matrix cooling and impingement cooling were investigated. Rib turbulated cooling and impingement cooling are typically used in the leading edge or mid region of the airfoil and matrix cooling is mostly applied in the trailing edge region. Literature studies for each cooling method, covering both open literature and internal reports, were carried out in order to find correlations developed from tests. The correlations were compared and analyzed with focus on suitability for use in turbine conditions. The analysis resulted in recommendations about what correlations to use for each cooling method. For rib turbulated cooling in square or rectangular ducts, four correlations developed by Han and his co-workers [3.5], [3.8], [3.9] and [3.6] are recommended, each valid for different channel and rib geometries. For U-shaped channels, correlations of Nagoga [3.4] are recommended. Matrix cooling is relatively unknown in west, but has been used for many years in the former Soviet Union. Therefore available information in open literature is limited. Only one source of correlations was found. The correlations were developed by Nagoga [4.2] and are valid for closed matrixes. Siemens Gas Turbines are cooled with open matrixes, why further work with developing correlations is needed. For impingement cooling on a flat target plate, a correlation of Florschuetz et al. [5.7] is recommended for inline impingement arrays. For staggered arrays, both the correlations of Florschuetz et al. [5.7] and Höglund [5.8] are suitable. The correlations for impingement on curved target plate gave very different results. The correlation of Nagoga is recommended, but it is also advised to consult the other correlations when calculating heat transfer for a specific case. Another part of the work has been to investigate the codes of two heat transfer programs named Q3D and Multipass, used in the Siemens offices in Finspång and Lincoln, respectively. Certain changes in the code are recommended.

Engineers constantly seek advancements in the performance of aircraft and power generation engines, including, lower costs and emissions, and improved fuel efficiency. Nickel-base superalloys are the material of choice for turbine discs, which experience some of the highest temperatures and stresses in the engine. Engine performance is proportional to operating temperatures. Consequently, the high-temperature capabilities of disc materials limit the performance of gas-turbine engines. Therefore, any improvements to engine performance necessitate improved alloy performance. In order to take advantage of improvements in high-temperature capabilities through tailoring of alloy microstructure, the overall objectives of this work were to establish relationships between alloy processing and microstructure, and between microstructure and mechanical properties. In addition, the project aimed to demonstrate the applicability of neural network modeling to the field of Ni-base disc alloy development and behavior. A full program of heat-treatment, microstructural quantification, mechanical testing, and neural network modeling was successfully applied to next generation Ni-base disc alloys. Mechanical testing included hot tensile, hot hardness, creep deformation, creep crack growth, and fatigue crack growth. From this work the mechanisms of processing-structure and structure-property relationships were studied. Further, testing results were used to demonstrate the applicability of machine-learning techniques to the development and optimization of this family of superalloys.

The present work has been an experimental investigation to evaluate the applicability of gas turbine cooling technology. With the temperature of the mainstream gas entering the turbine elevated above the melting temperature of the metal components, these components must be cooled, so they can withstand prolonged exposure to the mainstream gas. Both external and internal cooling techniques have been studied as a means to increase the life of turbine components. Detailed film cooling effectiveness distributions have been obtained on the turbine blade platform with a variety of cooling configurations. Because the newly developed pressure sensitive paint (PSP) technique has proven to be the most suitable technique for measuring the film effectiveness, it was applied to a variety of platform seal configurations and discrete film flows. From the measurements it was shown advanced seals provide more uniform protection through the passage with less potential for ingestion of the hot mainstream gases into the engine cavity. In addition to protecting the outer surface of the turbine components, via film cooling, heat can also be removed from the components internally. Because the turbine blades are rotating within the engine, it is important to consider the effect of rotation on the heat transfer enhancement within the airfoil cooling channels. Through this experimental investigation, the heat transfer enhancement has been measured in narrow, rectangular channels with various turbulators. The present experimental investigation has shown the turbulators, coupled with the rotation induced Coriolis and buoyancy forces, result in non-uniform levels of heat transfer enhancement in the cooling channels. Advanced turbulator configurations can be used to provide increased heat transfer enhancement. Although these designs result in increased frictional losses, the benefit of the heat transfer enhancement outweighs the frictional losses.

The heat transfer characteristics of airflows in serpentine cooling channels in stator vanes of gas turbines and the novel QuTech® Heat Pipe (QTHP) for electronic cooling applications were studied. The cooling channels are modeled as smooth and roughened two-pass trapezoidal channels with a 180° turn over a range of Reynolds numbers between about 10,000 and 60,000. The naphthalene sublimation technique and the heat and mass transfer analogy were applied. The results showed that there was a very large variation of the local heat (mass) transfer distribution in the turn and downstream of the turn. The local heat (mass) transfer was high near the end wall and the downstream outer wall in the turn and was relatively low in two regions near the upstream outer wall and the downstream edge at the tip of the divider wall in the turn. The variation of the local heat (mass) transfer was larger with ribs on two opposite walls than with smooth walls. The regional average heat (mass) transfer was lower in the turn and higher in the entire channel with the flow entering the channel through the larger straight section than when the flow was reversed. The pressure drop across the turn was higher with the flow entering the channel through the larger channel than when the flow was reversed. Thermal performance of the QuTech® Heat Pipe was identified over a range of inclination angles between 90° and -90° and thermal mechanism of the QTHP was studied with GC-MS, ICP-OES, XRD, XPS, and DSC. This study resulted in the following findings: the performance of the QTHP was severely dependent on gravity; the QTHP utilizes water as working fluid; there were inorganic components such as Na, K, P, S, and Cr, etc.; and the vaporization temperature of the working fluid (mostly water) was lower than the boiling temperature of pure water. This was due to the presence of inorganic salt hydrates in the QTHP. It may be concluded that thermal performance of heat pipes increases with additional latent heat of fusion energy and energy required to release water molecules from salt hydrates.

Gas turbine engines are extensively used in the aviation and power generation industries. They are used as topping cycles in combined cycle power plants, or as stand alone power generation units. Gains in thermodynamic efficiency can be realized by increasing the turbine inlet temperatures. Since modern turbine inlet temperatures exceed the melting point of the constituent superalloys, it is necessary to provide an aggressive cooling system. Relatively cool air, ducted from the compressor of the engine is used to remove heat from the hot turbine blade. This air flows through passages in the hollow blade (internal cooling), and is also ejected onto the surface of the blade to form an insulating film (film cooling). Modern land-based gas turbine engines use high Reynolds number internal flow to cool their internal passages. The first part of this study focuses on experiments pertaining to passages with Reynolds numbers of up to 400,000. Common turbulator designs (45degree parallel sharp-edged and round-edged) ribs are studied. Older correlations are found to require corrections in order to be valid in the high Reynolds number parameter space. The effect of rotation on heat transfer in a typical three-pass serpentine channel is studied using a computational model with near-wall refinement. Results from this computational study indicate that the hub experiences abnormally high heat transfer under rotation. An experimental study is conducted at Buoyancy numbers similar to an actual engine on a wedge shaped model trailing edge, roughened with pin-fins and equipped with slot ejection. Results show an asymmetery between the leading and trailing surfaces due to rotation - a difference which is subdued due to the provision of pin-fins. Film cooling effectiveness is measured by the PSP mass transfer analogy technique in two different configurations: a flat plate and a typical high pressure turbine blade. Parameters studied include a step immediately upstream of a row of holes; the Strouhal number (quantifying rotor-stator interaction) and coolant to mainstream density ratio. Results show a deterioration in film cooling effectiveness with on increasing the Strouhal number. Using a coolant with a higher density results in higher film cooling effectiveness.

Improvements to gas turbine efficiency depend closely on cooling technologies, as efficiency increases with turbine inlet temperature. To aid in this process, simulations that consider real engine conditions need to be considered. The first step towards this goal is a benchmark study using direct numerical simulations to consider a single periodic film cooling hole that characterizes the error in adiabatic boundary conditions, a common numerical simpliflication. Two cases are considered: an adiabatic case and a conjugate case. The adiabatic case is for validation to previous work conducted by Pietrzyk and Peet. The conjugate case considers heat transfer in the solid endwall in addition to the fluid, eliminating any simplified boundary conditions. It also includes an impinging jet and plenum, typical of actual endwall configurations. The numerical solver is NEK5000 and the two cases were run at 504 and 128 processors for the adiabatic and conjugate cases respectively. The approximate combined time is 100,000 CPU hours. In the adiabatic case, the results show good agreement for average velocity profiles but over prediction of the film cooling effectiveness. A convergence study suggests that there may be an area of unresolved flow, and the film cooling momentum flux may be too high. Preliminary conjugate results show agreement with velocity profiles, and significant differences in cooling effectiveness. Both cases will need to be refined near the cooling hole exit, and another convergence study done. The results from this study will be used in a larger case that considers an actual turbine vane and film cooling hole arrangement with real engine conditions.

This experimental study consists of two parts. For the first part, the film cooling effectiveness for a single row of seven cylindrical holes with a compound angle is measured on a flat surface using five different measurement techniques: steady-state liquid crystal thermography, transient liquid crystal thermography, pressure sensitive paint (PSP), thermocouples, and infrared thermography. A comparison of the film cooling effectiveness from each of the measurement techniques is presented. All methods show a good comparison, especially for the higher blowing ratios. The PSP technique shows the most accurate measurements and has more advantages for measuring film cooling effectiveness. Also, the effect of blowing ratio on the film cooling effectiveness is investigated for each of the measurement techniques. The second part of the study investigates the effect of hole geometries on the film cooling effectiveness using pressure sensitive paint. Nitrogen is injected as the coolant air so that the oxygen concentration levels can be obtained for the test surface. The film effectiveness is then obtained by the mass transfer analogy. Five total hole geometries are tested: fan-shaped laidback with a compound angle, fan-shaped laidback with a simple angle, a conical configuration with a compound angle, a conical configuration with a simple angle, and the reference geometry (cylindrical holes) used in part one. The effect of blowing ratio on film cooling effectiveness is presented for each hole geometry. The spanwise averaged effectiveness for each geometry is also presented to compare the geometry effect on film cooling effectiveness. The geometry of the holes has little effect on the effectiveness at low blowing ratios. The laterally expanded holes show improved effectiveness at higher blowing ratios. All experiments are performed in a low speed wind tunnel with a mainstream velocity of 34 m/s. The coolant air is injected through the coolant holes at four different coolant-to-mainstream velocity ratios: 0.3, 0.6, 1.2, and 1.8.

The Government of India has an ambitious mission of ¡¥power for all by 2012¡¦. This mission would require that the installed generation capacity should be at least 200,000 MW by 2012 from the present level of 114,000 MW. To be able to deliver this power to the entire nation, an expansion of the regional transmission grid-network and inter regional capacity to transmit power would be essential. The latter is required because resources are unevenly distributed in the country and power needs to be transmitted through great distances to areas where load centres exist. Indian government¡¦s ambitious plan can be met. Power generation is one thing but distribution and last mile delivery is a real challenge in remote rural India. 70% of India still lives in such rural settings. India is also notorious for loss of power in distribution due to its out dated distribution infrastructure and mismanagement. A lot is being done to improve the situation however to fast remedy the problem; government and private players can play an important role in setting up small power plants that are based on eco-friendly and efficient mode of power generation. India¡¦s western states and North eastern states are rich in natural gas. Unfortunately these areas are also remote, especially the North Eastern sector. Delivering power is quite a challenge. In search for a solution to this challenge we could be wise to choose greener solutions than otherwise. In the quest of which solution would be suitable for the chosen project, one could look across an array of available conventional and non-conventional sources of energy. Utilizing the locally available natural gas would be a right strategy. It also suits as a green choice. To exploit the availability of natural gas we would need technologies that are of right scale and are easily executable. A multi-million dollar mega gas power generation plant is neither plausible nor executable in those rural settings; however something of a smaller scale could be a good fit. There we see an opportunity for a green technology that may work wonder. Taiwan based Green Power Engineering Corporation has a solution in the form of their cutting edge gas turbine generator. With ease of setup and efficiency coupled with eco-friendly technology, the Gas turbine generators has the potential to be the solution to the much needed rural development by providing them continuous power.

Superalloys are widely applied as materials for components in the hot section of gas turbines. As superalloys have a limited oxidation life, the application of a coating is vital. The most commonly applied coatings in stationary gas turbines are MCrAlY coatings. Since the turbine components are exposed to high cyclic thermal stresses, MCrAlY coatings must also show a high thermal fatigue resistance. In this thesis, the effect of Cobalt and Rhenium on microstructure, oxidation and thermal fatigue of NiCoCrAlY coatings is presented. Additionally the condition of the coatings after testing in an industrial gas turbine is shown. The influence of Cobalt and Rhenium on coating microstructure was investigated by thermodynamic modelling and by metallography. It could be shown that both elements reduce the γ`-phase fraction and increase the β-phase fraction owing to an expansion of the γ+β field in the phase diagram. Modelling showed that Rhenium promotes the formation of α-Cr, which could be explained by a shift of the α-Cr solvus to higher temperatures and lower Cr concentrations. In the real coatings Re causes the precipitation of TCP-phase. The oxide scale growth rate is increased by Cobalt and Rhenium and it appears that Yttrium plays a significant role for that effect. Coating consumption due to simultaneous oxidation and interdiffusion could be decreased by the application of Cobalt and Rhenium. In thermal fatigue testing Rhenium reduces the time to crack initiation and increases crack propagation rate, although it could be shown that Rhenium increases the creep resistance of the coating. The effect could be explained by the influence of Rhenium on the microstructure, which increases creep resistance, but also reduces the ductility of the coating.