Top PDF Design and Analysis of Gas Turbine Blade by Potential Flow Approach

Design and Analysis of Gas Turbine Blade by Potential Flow  Approach

Design and Analysis of Gas Turbine Blade by Potential Flow Approach

The design features of the turbine segment of the gas turbine have been taken from the “preliminary design of a power turbine for maximization of an existing turbojet engine”. It was observed that in the above design, after the rotor blades being designed they were analyzed only for the mechanical stresses. As the temperature has a significant effect on the overall stress in the rotor blades, a detailed study is carried out on the temperature effects to have a clear understanding of the combined mechanical and the thermal stresses. The first stage rotor blade of the gas turbine is analyzed for the mechanical axial and centrifugal forces.
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Modal and Probabilistic Analysis of Wind Turbine Blade under Air-Flow

Modal and Probabilistic Analysis of Wind Turbine Blade under Air-Flow

Fin ite Ele ment Analysis (FEA) is a numerical simu lation method that can be used to calculate the response of a comp licated structure due to the application of fo rcing functions, which could be used to demonstrate the nonlinear large- deflection structural coupling for a fluid do main. This method is a powerful computational technique for approximate solutions to a variety of “real- world” engineering problems having complex domains subjected to general boundary conditions. FEA has become an essential step in the design or modeling of a physical phenomenon in various engineering disciplines. A physical phenomenon usually occurs in a continuum of matter (solid, liquid, or gas) involving several fie ld variables. The fie ld variables vary fro m point to point, thus possessing an infinite number of solutions in the domain [4].
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Exergoeconomic performance optimization of an endoreversible intercooled regenerated Brayton cogeneration plant. Part 1: Thermodynamic model and parameter analyses

Exergoeconomic performance optimization of an endoreversible intercooled regenerated Brayton cogeneration plant. Part 1: Thermodynamic model and parameter analyses

Exergoeconomic (or thermoeconomic) analysis and optimization [29, 30] is a relatively new method that combines exergy with conventional concepts from long-run engineering economic optimization to evaluate and optimize the design and performance of energy systems. Salamon and Nitzan [31] combined the endoreversible model with exergoeconomic analysis for endoreversible Carnot heat engine with the only loss of heat resistance. It was termed as finite time exergoeconomic analysis [32-38] to distinguish it from the endoreversible analysis with pure thermodynamic objectives and the exergoeconomic analysis with long-run economic optimization. Furthermore, such a method has been extended to endoreversible Carnot heat engine with complex heat transfer law [39], universal endoreversible heat engine [40], generalized irreversible Carnot heat engine [41], generalized irreversible Carnot heat pump [42] and universal irreversible steady flow variable-temperature heat reservoir heat pump [43]. On the bases of Refs. [32-38]. Tao et al. [44, 45] performed the finite time exergoeconomic performance analysis and optimization for an endoreversible simple [44] and regenerative [45] gas turbine closed-cycle heat and power cogeneration plant coupled to constant temperature heat reservoirs by optimizing the heat conductance allocations among the hot-, cold- and consumer-side heat exchangers, the regenerator and the pressure ratio of the compressor.
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Numerical analysis of flow around a fan blade of a CFM56-3

Numerical analysis of flow around a fan blade of a CFM56-3

the turbofan engine were created for civilian application in general. The turbofan design was conceived in order to improve the fuel ef ciency, using the relationship stated before, high mass ows with low ow speeds. The turbofan engine has an additional component, the Fan, that is installed at the engine inlet in order to increase the amount of air admitted to the engine. However, the inlet air ow is divided and part is directed to the core of the engine, toward the compressor, combustion chamber and turbine, undergoing in the GTE process explained before, the other part is bypassed through a duct, which ends in a nozzle, this ow undergoes in a momentum exchange with the airframe and the resulting thrust does not require any burn of fuel, but some work is derived from the turbine to drive the fan [1]. Even with this extra power that is required to drive the fan, the total thrust (bypassed+core) achieved, requires less burned fuel than the necessary to obtain that thrust in a normal GTE (without bypass) [1]. The most common turbofan is the two-spool, in this design, the fan, LPC and LPT are connected by one shaft (1st Spool LP) and thus rotate synchronously. The HPC and HPT are divided by the combustion chamber and are connected by another shaft (2nd shaft HP) usually concentric with the LP shaft [2]. Turbofan engines are classi ed by their bypass ratio (BPR) that can be de ned as the ratio of bypass to core mass ows. State of the art engines can have bypass ratio as high as 16,6 (Kuznetsov nk-93, Russian engine) in other hand some early turbofans used ratios as low as 0,3. Based on the relation discussed previously we can see that bypass ratio is chosen to prioritize either fuel ef ciency or aircraft speed. The core exhaust has a higher velocity than the bypass exhaust, and when the bypass ratio is high a large and slow mass of air is passing through the bypass nozzle, in this design the thrust is created due to high mass ow movement rather than high exhaust velocity. To maintain the same thrust with a smaller bypass ratio its necessary to increase the velocity of the bypass ratio ow by same factor. In both designs the resulting thrust is the same, but there is a difference in terms of fuel ef ciency, mainly because, in the low bypass ratio design more fuel has to be burned since the core ow increases and the fuel air ratio needs to be approximately the same [1].
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Mechanisms of Water Droplets Deposition on Turbine Blade Surfaces and Erosion Wear Effects

Mechanisms of Water Droplets Deposition on Turbine Blade Surfaces and Erosion Wear Effects

flow. Some of these drops may be too large in size to be stable. All drops with smaller diameter have same velocity as that of the steam. The others with large diameter (100-200 micron or up to 500 micron) with high relative velocity go straight and hit the moving blade and cause blades erosion. In the axial clearance occurs acceleration of secondary drops formed when the film of condensate is descending from blades of the rotor splits, and thrusting of drops onto the peripheral surface due to the peripheral component of speed which is imparted to the flow in the stator space. When liquid impacts on the material surface, it behaves as a compressible fluid, in the early stage, and the so called ‘‘water hammer’’ pressure can be generated. This high pressure is responsible for most of damages resulting from the liquid impact, and the high pressure is maintained while the edge of the contact area between the impacting liquid and the solid moves supersonically with respect to the shock speed in the liquid (Xu Wanli et al., 2010). Contemporary research works are focused on condensation modeling, numerical modeling and analysis of erosion parameters and their impact on blade surfaces, Hamed et al., Fiore and Selig (2014), Nikkhani, Shams, Ziabashrhadh (2009) and Hasril et al. Based on erosion rate and droplet models, the erosion characteristics of first row blades, in a supercritical steam turbine, was simulated and analyzed by three-dimension numerical simulation method in the research of Liu- xi et al. (2014). The influence of operating conditions, droplets size distribution at the nozzle’s inlet and at the axial clearance on the erosion in cascades, nucleation models and many others, are explored and discussed by many researchers - Hamed et al., Liu-xi Cai et al. (2014), Nikkhani, Shams and Ziabashrhadh (2009), Hasril et al., and Wroblewski et al. (2009).
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Exergoeconomic performance optimization of an endoreversible intercooled regenerative Brayton combined heat and power plant coupled to variable-temperature heat reservoirs

Exergoeconomic performance optimization of an endoreversible intercooled regenerative Brayton combined heat and power plant coupled to variable-temperature heat reservoirs

Finite-time thermodynamics (FTT) [6-18] is a powerful tool for analyzing and optimizing performance of various thermodynamic cycles and devices. Some authors have performed the performance analysis and optimization for various CHP plants by using finite-time thermodynamics. Bojic [19] investigated the annual worth of an endoreversible Carnot cycle CHP plant with the sole irreversibility of heat resistance. Sahin et al [20] performed exergy output rate optimization for an endoreversible Carnot cycle CHP plant and found that the lower the consumer-side temperature, the better the performance. Erdil et al [21] optimized the exergetic output rate and exergetic efficiency of an irreversible combined Carnot cycle CHP plant under various design and operating conditions and found that the optimal performance stayed approximately constant with consumer-side temperature. Atmaca et al [22] performed the exergetic output rate, energy utilization factor (EUF), artificial thermal efficiency and exergetic efficiency optimization of an irreversible Carnot cycle CHP plant. Ust et al [23] provided a new exergetic performance criterion, exergy density, which includes the consideration of the system sizes, and investigated the general and optimal performances of an irreversible Carnot cycle CHP plant.
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Investigation into the flow details of runner region in a pump turbine at off-design conditions

Investigation into the flow details of runner region in a pump turbine at off-design conditions

the pump turbine, the discharge-speed as well as torque-speed characteristics at constant guide vane opening can be ‘‘S-Shaped.’’ 2 In this case, the machine operation may become strongly unstable at runaway speed and beyond, with a significant increase in struc- tural vibrations and noise. Moreover, a stable runaway operating point is difficult to be reached and therefore the synchronization with the electrical network in safety conditions becomes impossible. 3 In this case, one rotational speed may correspond to three discharge val- ues, which will inevitably increase mechanical vibra- tions and noises to a larger extent. Most of all, it is difficult for the hydraulic machine to be synchronous with the power network. The existence of S shape char- acteristic in low head start of a pump turbine is the restriction of the pump turbine development. This will induce large pressure pulsations and vibrations in pump turbines. 4–6 And this characteristic of reversible pump turbine will lead to severe difficulties in the tran- sition process of generators cut-in.
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Pitch Angle Control of Variable Speed Wind Turbine

Pitch Angle Control of Variable Speed Wind Turbine

Blade pitch control is primarily used to limit the aerodynamic power above rated wind speed in order to keep the turbine shaft torque within its design limits. The inertia of the blades turned by the drive is large and the pitch actuator has thus limited capabilities. Its dynamics are non-linear with saturation limits on pitch angle (usually from -3°-90°) and pitching speed rate (around 8°-10° sec −1 ). In this study, two pitch angle control structures are evaluated.

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Investigation of novel propulsion systems – the exoskeletal engine concept. Part I

Investigation of novel propulsion systems – the exoskeletal engine concept. Part I

Abstract: The exoskeletal engine represents a relatively new concept in the world of propulsion systems. It is a drum-rotor engine concept in which conventionally heavy shafts and discs are eliminated and replaced by rotating casings that support the blades in span wise compression. Thus the rotating blades are in compression rather than in tension. The resulting open channel at the engine centreline has an immense potential for the jet noise reduction and can also accommodate an inner combined-cycle thruster such as a ramjet. This is the first part of an article constituted out of two parts.
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A New Approach To The Rule-Based Systems Design And Implementation Process

A New Approach To The Rule-Based Systems Design And Implementation Process

The third issue is that design approaches do not offer integrated computer de- velopment tools (CASE ) supporting the rule-based system building process at all stages – from the design to implementation phase. Existing methods support main- ly subsequent stages of the conceptual design in case of large systems, while direct technical support of the logical design and during the implementation phase is mostly limited to providing a context-sensitive, syntax checking editors, or simple wizards that support the design process. Most of the available CASE tools have the follow- ing limitations: no integrated design and implementation process specialization, and limited analysis facilities.
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Development of Velocity Flow Field Measurement Method Around a Vertical Axis Wind Turbine Blade Using Particle Image Velocimetry

Development of Velocity Flow Field Measurement Method Around a Vertical Axis Wind Turbine Blade Using Particle Image Velocimetry

good indication of the onset of dynamic stall. At θ = 70° (Fig. 10b), the growth of a leading edge vortex (LEV) is initiated and is seen to continue to develop until it fully forms and starts to detach from the blade (Fig. 10c). Following this, another vortex forms at the trailing edge (TEV) that facilitates the detachment of the LEV (Fig. 10d) and itself is detached from the blade surface (Fig. 10e). The process of the alternate shedding of vortices akin to the Kármán Vortex Street occurs until the separation depth starts to shallow out and the blade stall reduces due to the decrease of the perceived angle of attack. At Fig. 10f, blade stall is still deep with the separation point still within quarter chord from the leading edge. Once again, classical static aerofoil theory suggests that the angle of attack at this condition is below stall and the flow should be fully attached by this time. On the contrary, full reattachment only happens after θ = 1λ0° (not shown) which is way past the halfway point in a full rotor revolution, at which α would be expected to be zero.
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Design And Construction Of 300W Audio Power Amplifier For Classroom

Design And Construction Of 300W Audio Power Amplifier For Classroom

FET is controlled by the input gate voltage and BJT is controlled by the input base current. The cost of the BJT is much lower cost than FET. The losses of the BJT are lower than FET. The trans conductance of the BJT is higher than FET. By using BJT, BJT can give low current and low voltage supply. BJT is good in amplification. By using FET, FET can give high current and high voltage supply. FET is not good in amplification. To get the high power, FET can be used. ————————————————
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Thermodynamic, Economic and Emissions Analysis of a Micro Gas Turbine Cogeneration System operating on Biofuels

Thermodynamic, Economic and Emissions Analysis of a Micro Gas Turbine Cogeneration System operating on Biofuels

Nevertheless, fuel-fired power plants will remain the predominant source for power generation in the foreseeable future, because alternative energies such as nuclear power, solar power, wind power and hydropower all underlie their own limitations and problems such as environmental impacts, disproportionately high costs, fluctuating generating conditions and regional restrictions, to only name a few. Therefore, the most promising methods to reduce the greenhouse gases in the atmosphere are the use of alternative fuels such as biogas or syngas (obtained from biomass) and enhancing the power plant efficiency by decreasing the percentage of useful energy lost to the environment. The main advantage of biogas and syngas, besides being renewable energy sources, is that their use in thermal power plants is considered cleaner than natural gas (NG) use, in regard to the whole life cycle of the carbons. As a result, the carbon-dioxide-equivalents of the emissions released into the atmosphere are lower, which reduces the environmental impacts, especially regarding global warming. Additionally, the use of biogas or syngas can counteract against the imminent depletion of fossil fuels. Furthermore, whereas efficiency optimisation of a particular machine in a power plant, e.g. gas turbine or compressor, is a very longsome development, cogeneration is a relatively simple and quickly applicable method to significantly increase the overall efficiency of any thermal power plant. Cogeneration is defined as the simultaneous generation of mechanical energy and useful heat, e.g. power and saturated steam.
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J. Aerosp. Technol. Manag.  vol.5 número1

J. Aerosp. Technol. Manag. vol.5 número1

using different settings on wind speed, rotational speed and pitch angle. The method couples the momentum theory with local events taking place at the actual blades. The blade is analyzed as a number of independent stream tubes. In each one, the induced velocity is calculated by performing the conservation of momentum, and the aerodynamic forces are found with the 2D aerodynamic theory and airfoil data. The stream tubes are discretized into N annular elements. The lateral boundary of the elements does not admit any flow across them. Some assumptions are made for the annular elements: no radial dependence, that is, one element cannot be affected by the others; the forces from the blade on the flow are constant in each annular element, corresponding to a rotor with a number of blades.
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Analysis of quality and cost of FeSiMg treatment master alloy vs. cored wire in production of ductile cast iron

Analysis of quality and cost of FeSiMg treatment master alloy vs. cored wire in production of ductile cast iron

Another important aspect of this nodularising treatment is without any doubt the very encouraging cost of the nodulariser, and therefore the aim of this study has been an assessment of the cost of the FeSiMg5% as compared with the nodularisers used in the form of cored wire.

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Study of Biodiesel Emissions and Carbon Mitigation in Gas Turbine Combustor

Study of Biodiesel Emissions and Carbon Mitigation in Gas Turbine Combustor

ABSTRACT : The energy security and reduction of carbon emissions have accelerated the R&D of the alternative fuels in the transport, heating and power generation sectors in last decade. The heating and power generation sectors are two of the major contributors to carbon dioxide emissions, which are due to the combustion of petroleum fuels. A gas turbine combustor test rig was used to study the combustion and emission characteristics of waste cooking oil methyl ester (WME) biodiesel. A 140mm diameter atmospheric pressure premixed combustion test rig was used at 600K inlet air temperature and Mach number 0.017. The tests were conducted using pure WME and blend with kerosene. The central fuel injection was used for liquid fuels and wall injection was used for NG (Natural Gas). The exhaust samples for smoke and gaseous emissions (NOx, UHC, CO and CO₂) have been analysed on dry basis and corrected to 15% O₂ over range of different fuel rate. The results showed that the biodiesel had lower CO, UHC emissions and higher NOx emissions than the kerosene. The blend B20 had lowest NOx emissions comparing with pure biodiesel (B100) and B50. The optimum conditions for WME with lowest emissions were identified. The carbon dioxide emissions per 100 megawatts of heat generated for each fuel were calculated. The relative carbon emissions and mitigations by biodiesel were compared. The results can be used to estimate pollutant emissions and carbon reductions by biodiesel in power generation industry and other sectors where gas turbine engines are used.
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Analysis of Structure and Abrasion Resistance of the Metal Composite Based on an Intermetallic FeAl Phase with VC and TiC Precipitates

Analysis of Structure and Abrasion Resistance of the Metal Composite Based on an Intermetallic FeAl Phase with VC and TiC Precipitates

Molten metal with the composition of high-aluminium cast iron was superheated to a temperature of 1510°C, and then samples were cast at 1420°C for metallographic examinations. To thus prepared liquid cast iron, vanadium was next introduced in the form of ferroalloy The titanium to second heat was introduced in figure of scraps of titanic sheet metal. Consequently, cast iron of the chemical composition given in Table 1 was obtained. Samples were poured into dry moulds prepared from the traditional bentonite-bonded sand. From these samples, metallographic specimens were prepared.
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3 ∗ 1 Laboratório de Produtos Naturais, PN3, Far-Manguinhos, FIOCRUZ Rua Sizenando Nabuco, 100, 21041-250 Rio de Janeiro, RJ, Brasil

3 ∗ 1 Laboratório de Produtos Naturais, PN3, Far-Manguinhos, FIOCRUZ Rua Sizenando Nabuco, 100, 21041-250 Rio de Janeiro, RJ, Brasil

Analysis by Gas Chromatography and Gas Chromatography/Mass Spectrometry of the essential oils obtained from leaves of Echinodorus grandiflorus (“Chapéu de couro”) from two different populations (Big Leaves and Small Leaves), collected monthly between September 1998 and December 1999 revealed 17 compo- nents. Phytol was the major constituent for both populations. The main sesquiterpene representatives are (E )−caryophyllene, α-humulene and (E)-nerolidol.

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Application of an artificial neural network in the use of  properties as a low cost proxy of power transformers DGA data

Application of an artificial neural network in the use of properties as a low cost proxy of power transformers DGA data

This paper is about the relationship between dissolved gases and the quality of the insulating mineral oil used in power transformers. Artificial Neural Networks are used to approach operational conditions assessment issue of the insulating oil in power transformers, which is characterized by a non-linear dynamic behavior. The operation conditions and integrity of a power transformer can be inferred by analysis of physicochemical and chromatographic (DGA – Dissolved Gas Analysis) profiles of the isolating oil, which allow establishing procedures for operating and maintaining the equipment. However, while the costs of physicochemical tests are less expensive, the chromatographic analysis is more informative and reliable. This work presents a method that can be used to extract chromatographic information using physicochemical analysis through Artificial Neural Networks. It´s believed that, the power utilities could improve reliability in the prediction of incipient failures at a lower cost with this method. The results show this strategy might be promising. The purpose of this work is the direct implementation of the diagnosis of incipient faults through the use of physicochemical properties without the need to make an oil chromatography.
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Gas turbine emissions in airports vicinity during LTO cycles

Gas turbine emissions in airports vicinity during LTO cycles

[GAS TURBINE EMISSIONS IN AIRPORTS VICINITY DURING LTO CYCLES] be emitted by modern engines, but the particles are generally smaller in size and often fewer in number as well. In order to quantify the particulate emissions and to capture the trends as engine technology advances, measurements are now focusing on the total mass of particulate matter, along with a consideration of the particle size and number. Again, it is of interest to consider what is taking place in the engine exhaust plume. The particles leaving the engine are predominantly black carbon, but other primary particles, often too small to measure, may also be present; in addition to the precursor gaseous components which will later add to the particle mass. Apart from the NOx and CO, these gaseous components and smaller particles are volatile hydrocarbons and sulphur compounds. These volatile compounds can then condense into volatile particles downstream from the engine exhaust to form new particles of environmental concern. These same volatile species also condense on the existing soot particles, coating their surface. As with the NOx components, the quantities of these particles and volatile compounds vary with engine power setting in both absolute and relative terms. The proportion of volatile components is greatest at idle, while black carbon predominates at high power settings. The need to pay more attention to the size, number and composition of particles for health-related reasons is complicated by the difficulties encountered in trying to take the necessary measurements in the high temperature/high gas velocity environment at the engine exhaust plane. Furthermore, there is the complication that the volatile particles form downstream of the engine exhausts, and thus are not present where certification measurements are taken. Considerable research work is in progress to try to resolve these issues.
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