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1
Kosowski, Krzysztof, and Marian Piwowarski. "Design Analysis of Micro Gas Turbines in Closed Cycles." Energies 13, no. 21 (November 5, 2020): 5790. http://dx.doi.org/10.3390/en13215790.
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The problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blade heights and a high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work in a similar range of temperatures and the same pressure ratios, but in the range of smaller pressure values and smaller mass flow rate. Thus, we can obtain a gas turbine of a very small output but of the efficiency typical of gas turbines with a much higher power. In this paper, the results of the thermodynamic calculations of the turbine cycles are discussed and the designed gas turbine flow parts are presented. Suggestions of the design solutions of micro gas turbines for different values of power output are proposed. This new approach to gas turbine arrangement makes it possible to build a gas turbine unit of a very small output and a high efficiency. The calculations of cycle and gas turbine design were performed for different cycle parameters and different working media (air, nitrogen, hydrogen, helium, xenon and carbon dioxide).
2
Yang, Xiaoyong, Zhenjia Yu, Xiaoli Yu, and Jie Wang. "ICONE19-43289 EFFECTS OF FLOW LOSSES ON EFFICIENCY OF HTGR GAS TURBINE CYCLE." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_125.
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Valenti, Michael. "Keeping it Cool." Mechanical Engineering 123, no. 08 (August 1, 2001): 48–52. http://dx.doi.org/10.1115/1.2001-aug-2.
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This article provides details of various aspects of air cooling technologies that can give gas turbines a boost. Air inlet cooling raises gas turbine efficiency, which is proportional to the mass flow of air fed into the turbine. The higher the mass flow, the greater the amount of electricity produced from the gas burned. Researchers at Mee Industries conduct laser scattering studies of their company’s fogging nozzles to determine if the nozzles project properly sized droplets for cooling. The goal for turbine air cooling systems is to reduce the temperature of inlet air from the dry bulb temperature, the ambient temperature, to the wet bulb temperature. The Turbidek evaporative cooling system designed by Munters Corp. of Fort Myers, Florida, is often retrofit to turbines, typically installed in front of pre-filters that remove particulates from inlet air. Turbine Air Systems designs standard chillers to improve the performance of the General Electric LM6000 and F-class gas turbines during the hottest weather.
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Wilson, Jay M., and Henry Baumgartner. "A New Turbine for Natural Gas Pipelines." Mechanical Engineering 121, no. 05 (May 1, 1999): 72–74. http://dx.doi.org/10.1115/1.1999-may-7.
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The new Cooper-Bessemer power turbine is a high-efficiency, center frame-mounted, three-stage unit that can be driven by either the existing RB211-24 gas generator or the new improved version. The upgraded gas generator combined with the new power turbine offers an increase in nominal output from 28.4 MW (38,000 hp) to 31.8 MW (42,600 hp). The new coupled turbine, now being tested, is called the Coberra 6761. Besides improving core engine performance, the program's objectives included improved fuel efficiency and reliability, and easier site serviceability; extension of the modular concept from the gas generator into the power turbine with improvements in sealing, materials, and temperature capability as well as interchangeability of both upgraded turbines with existing hardware. The Rolls-Royce industrial RB211 turbine, derived from an aircraft engine, is the basis for the gas generator end of Cooper Energy Services' Coberra coupled turbines. The power turbine design capacity has a significant effect on the power at a given speed. The flow capacity was optimized to achieve the best thermal efficiency and lower IP speeds to optimize IP compressor efficiency and permit future throttle push.
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Rodgers, C. "Impingement Starting and Power Boosting of Small Gas Turbines." Journal of Engineering for Gas Turbines and Power 107, no. 4 (October 1, 1985): 821–27. http://dx.doi.org/10.1115/1.3239817.
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The technology of high-pressure air or hot-gas impingement from stationary shroud supplementary nozzles onto radial outflow compressors and radial inflow turbines to permit rapid gas turbine starting or power boosting is discussed. Data are presented on the equivalent turbine component performance for convergent/divergent shroud impingement nozzles, which reveal the sensitivity of nozzle velocity coefficient with Mach number and turbine efficiency with impingement nozzle admission arc. Compressor and turbine matching is addressed in the transient turbine start mode with the possibility of operating these components in braking or reverse flow regimes when impingement flow rates exceed design.
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Крюков, Алексей, and Aleksei Kriukov. "Three dimensional gas-dynamic calculation of nozzle block of small flow-rate centripetal turbine." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2019, no. 4 (November 15, 2019): 89–95. http://dx.doi.org/10.24143/2073-1574-2019-4-89-95.
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The article describes the low-consumption turbines as reliable, productive, small-sized actuating mechanisms in various units and machines. Experience in production and use
of low-cost turbine stages contributes to improving the efficiency along with simplifying and re-ducing the cost of manufacturing of the blades and the stage in general. Improving the efficiency
of low-consumption turbines requires solving the problem of aerodynamic improvement of the flow part and the calculated determination of the optimal geometry and operating modes of the impeller flow. One of the innovative ways to improve the design efficiency of low-consumption turbines is the automation of the development process using modern modeling systems based on the developed software systems. Due to the small size of the design, the design calculations of turbine stages of this type have been made in a one-dimensional formulation with the involvement of various analogies with classical stages. Using three-dimensional gas dynamic calculations based on the ANSYS CFX platform will significantly improve the quality of design of flow parts of low-flow turbines. Implementation of three-dimensional gas-dynamic calculation of the nozzle unit using the software package ANSYS CFX low-consumption turbine stage can solve this problem. The geometric model is built using AutoCAD software, the grid is selected, the boundary conditions are set. The values of the experimental coefficients of the nozzle velocity, neck velocity and the tangential component of velocity at the nozzle outlet have been compared with the coefficients obtained when using the software package. There have been built the velocity fields and made conclusions about feasibility of using the ANSYS CFX software package to determine the main parameters of a three-dimensional flow of the turbine stage.
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Vidian, Fajri, Putra Anugrah Peranginangin, and Muhamad Yulianto. "Cycle-Tempo Simulation of Ultra-Micro Gas Turbine Fueled by Producer Gas Resulting from Leaf Waste Gasification." Journal of Mechanical Engineering 24, no. 3 (September 30, 2021): 14–20. http://dx.doi.org/10.15407/pmach2021.03.014.
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Leaf waste has the potential to be converted into energy because of its high availability both in the world and Indonesia. Gasification is a conversion technology that can be used to convert leaves into producer gas. This gas can be used for various applications, one of which is using it as fuel for gas turbines, including ultra-micro gas ones, which are among the most popular micro generators of electric power at the time. To minimize the risk of failure in the experiment and cost, simulation is used. To simulate the performance of gas turbines, the thermodynamic analysis tool called Cycle-Tempo is used. In this study, Cycle-Tempo was used for the zero-dimensional thermodynamic simulation of an ultra-micro gas turbine operated using producer gas as fuel. Our research contributions are the simulation of an ultra-micro gas turbine at a lower power output of about 1 kWe and the use of producer gas from leaf waste gasification as fuel in a gas turbine. The aim of the simulation is to determine the influence of air-fuel ratio on compressor power, turbine power, generator power, thermal efficiency, turbine inlet temperature and turbine outlet temperature. The simulation was carried out on condition that the fuel flow rate of 0.005 kg/s is constant, the maximum air flow rate is 0.02705 kg/s, and the air-fuel ratio is in the range of 1.55 to 5.41. The leaf waste gasification was simulated before, by using an equilibrium constant to get the composition of producer gas. The producer gas that was used as fuel had the following molar fractions: about 22.62% of CO, 18.98% of H2, 3.28% of CH4, 10.67% of CO2 and 44.4% of N2. The simulation results show that an increase in air-fuel ratio resulted in turbine power increase from 1.23 kW to 1.94 kW. The generator power, thermal efficiency, turbine inlet temperature and turbine outlet temperature decreased respectively from 0.89 kWe to 0.77 kWe; 3.17% to 2.76%; 782 °C to 379 °C and 705°C to 304 °C. The maximums of the generator power and thermal efficiency of 0.89 kWe and 3.17%, respectively, were obtained at the 1.55 air-fuel ratio. The generator power and thermal efficiency are 0.8 kWe and 2.88%, respectively, with the 4.64 air-fuel ratio or 200% excess air. The result of the simulation matches that of the experiment described in the literature.
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Rice, I. G. "Split Stream Boilers for High-Temperature/High-Pressure Topping Steam Turbine Combined Cycles." Journal of Engineering for Gas Turbines and Power 119, no. 2 (April 1, 1997): 385–94. http://dx.doi.org/10.1115/1.2815586.
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Research and development work on high-temperature and high-pressure (up to 1500°F TIT and 4500 psia) topping steam turbines and associated steam generators for steam power plants as well as combined cycle plants is being carried forward by DOE, EPRI, and independent companies. Aeroderivative gas turbines and heavy-duty gas turbines both will require exhaust gas supplementary firing to achieve high throttle temperatures. This paper presents an analysis and examples of a split stream boiler arrangement for high-temperature and high-pressure topping steam turbine combined cycles. A portion of the gas turbine exhaust flow is run in parallel with a conventional heat recovery steam generator (HRSG). This side stream is supplementary fired opposed to the current practice of full exhaust flow firing. Chemical fuel gas recuperation can be incorporated in the side stream as an option. A significant combined cycle efficiency gain of 2 to 4 percentage points can be realized using this split stream approach. Calculations and graphs show how the DOE goal of 60 percent combined cycle efficiency burning natural gas fuel can be exceeded. The boiler concept is equally applicable to the integrated coal gas fuel combined cycle (IGCC).
9
Godin, T., S. Harvey, and P. Stouffs. "High-Temperature Reactive Flow of Combustion Gases in an Expansion Turbine." Journal of Turbomachinery 119, no. 3 (July 1, 1997): 554–61. http://dx.doi.org/10.1115/1.2841157.
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The analysis of the chemical behavior of the working fluid in gas turbines is usually restricted to the combustion chamber sections. However, the current trend toward higher Turbine Inlet Temperatures (TIT), in order to achieve improved thermal efficiency, will invalidate the assumption of frozen composition of the gases in the first stages of the expansion process. It will become necessary to consider the recombination reactions of the dissociated species, resulting in heat release during expansion. In order to quantify the influence of this reactivity on the performance of high TIT gas turbines, a one-dimensional model of the reactive flow has been developed. Preliminary results were reported in a previous paper. The authors concluded that, in the case of expansion of combustion gases in a subsonic static uncurved distributor nozzle, the residual reactivity must be taken into account above a temperature threshold of around 2000 K. The present study extends these results by investigating the reactive flow in a complete multistage turbine set, including a transonic first-stage nozzle. A key result of this study is that heat release during the expansion process itself will be considerable in future high-temperature gas turbines, and this will have significant implications for turbine design techniques. Furthermore, we show that, at the turbine exit, the fractions of NO and CO are very different from the values computed at the combustor outlet. In particular, NO production in the early part of the expansion process is very high. Finally, the effects of temperature fluctuations at the turbine inlet are considered. We show that residual chemical reactivity affects the expansion characteristics in gas turbines with TITs comparable to those attained by modern high-performance machines.
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Choi, Seok Min, Seungyeong Choi, and Hyung Hee Cho. "Effect of Various Coolant Mass Flow Rates on Sealing Effectiveness of Turbine Blade Rim Seal at First Stage Gas Turbine Experimental Facility." Energies 13, no. 16 (August 7, 2020): 4105. http://dx.doi.org/10.3390/en13164105.
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The appropriate coolant mass flow of turbine blade rim seal has become an important issue as turbine blades are exposed to increasingly higher thermal load owing to increased turbine inlet temperature. If the coolant is deficient, hot gas ingresses to the rim seal, or if sufficient, the efficiency of turbine decreases. Therefore, we analyzed sealing effectiveness of rim seal derive appropriate coolant mass flow rate at various conditions. The experimental facility was modified from one designed for an aero-engine gas turbine. Rotational Reynolds number varied from 3 × 105 to 5 × 105 based on rotational speed. Pressure was measured at various locations in the shroud, endwall, and rim seal. CO2 concentration was measured at various rim seal locations to analyze sealing effectiveness. Measured results showed that 1.35% coolant mass flow rate of rim seal exhibited a little ingress effect, whereas lower coolant mass flow rates exhibited higher ingress effect. A predicted correlation for sealing effectiveness of rim seal was derived at various rotational Reynolds number and coolant mass flow rate. The correlation will be useful for turbine cooling design, helping to predict sealing effectiveness of rim seals during preliminary design processes for new gas turbines.
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Han, Je-Chin, and Srinath Ekkad. "Recent Development in Turbine Blade Film Cooling." International Journal of Rotating Machinery 7, no. 1 (2001): 21–40. http://dx.doi.org/10.1155/s1023621x01000033.
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Gas turbines are extensively used for aircraft propulsion, land-based power generation, and industrial applications. Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperature (RIT). The current RIT level in advanced gas turbines is far above the .melting point of the blade material. Therefore, along with high temperature material development, a sophisticated cooling scheme must be developed for continuous safe operation of gas turbines with high performance. Gas turbine blades are cooled internally and externally. This paper focuses on external blade cooling or so-called film cooling. In film cooling, relatively cool air is injected from the inside of the blade to the outside surface which forms a protective layer between the blade surface and hot gas streams. Performance of film cooling primarily depends on the coolant to mainstream pressure ratio, temperature ratio, and film hole location and geometry under representative engine flow conditions. In the past number of years there has been considerable progress in turbine film cooling research and this paper is limited to review a few selected publications to reflect recent development in turbine blade film cooling.
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Rusanov, Andrii V., Viktor L. Shvetsov, Anna I. Kosianova, Yurii A. Bykov, Natalia V. Pashchenko, Maryna O. Chuhai, and Roman A. Rusanov. "The Gas-Dynamic Efficiency Increase of the K-300 Series Steam Turbine Control Compartment." Journal of Mechanical Engineering 23, no. 4 (December 30, 2020): 6–13. http://dx.doi.org/10.15407/pmach2020.04.006.
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The paper proposes ways to increase the efficiency of nozzle control for steam power turbines of the K-300 series, that, along with the K-200 series turbines, form the basis of thermal energy in Ukraine. The object of study is considered to be the control compartment (CC) of the high-pressure cylinder (HPC) of the K-325-23.5 steam turbine. In the paper, the calculation and design of the control compartment of the steam turbine was performed using the complex methodology developed in IPMach NAS of Ukraine, that includes methods of different levels of complexity, from one-dimensional to models for calculation of spatial viscous flows, as well as analytical methods for spatial geometries of flow parts description based on limited number of parameterized values. The complex design methodology is implemented in the IPMFlow software package, which is a development of the FlowER and FlowER–U software packages. A model of a viscous turbulent flow is based on the numerical integration of an averaged system of Navier-Stokes equations, for the closure of which the two-term Tamman equation of state is used. Turbulent phenomena were taken into account using a SST Menter two-parameter differential turbulence model. The research was conducted for six operation modes in the calculation area, which consisted of more than 3 million cells (elementary volumes), taking into account the interdiscand diaphragm leakage. According to the results of numerical studies of the original control compartment of the K-325-23.5 steam turbine, it is shown that the efficiency in the flow part is quite low in all operation modes, including the nominal one (100% power mode), due to large losses of kinetic energy in the equalization chamber, as well as inflated load on the first stage. On the basis of the performed analysis of gas-dynamic processes, the directions of a control compartment flow part modernization are formed and themodernization itself is executed. In the new flow part, compared to the original one, there is a favorable picture of the flow in all operation modes, which ensures its high gas-dynamic efficiency. Depending on the mode, the efficiency of the control compartment increased by 4.9–7.3%, and the capacity increased by 1–2 MW. In the nominal mode (100% mode) the efficiency of the new control compartment, taking into account the interdisc and overbandage leakage, is 91%.
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Schädler, Rainer, Anestis I. Kalfas, Reza S. Abhari, Gregor Schmid, Tilmann auf dem Kampe, and Sanjay B. Prabhu. "Novel high-pressure turbine purge control features for increased stage efficiency." Journal of the Global Power and Propulsion Society 1 (July 21, 2017): 68MK5V. http://dx.doi.org/10.22261/68mk5v.
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AbstractRim seals throttle flow and have shown to impact the aerodynamic performance of gas turbines. The results of an experimental investigation of a rim seal exit geometry variation and its impact on the high-pressure turbine flow field are presented. A one-and-a-half stage, unshrouded and highly loaded axial turbine configuration with 3-dimensionally shaped blades and non-axisymmetric end wall contouring has been tested in an axial turbine facility. The exit of the rotor upstream rim seal was equipped with novel geometrical features which are termed as purge control features (PCFs) and a baseline rim seal geometry for comparison. The time-averaged and unsteady aerodynamic effects at rotor inlet and exit have been measured with pneumatic probes and the fast-response aerodynamic probe (FRAP) for three rim seal purge flow injection rates. Measurements at rotor inlet and exit reveal the impact of the geometrical features on the rim seal exit and main annulus flow field, highlighting regions of reduced aerodynamic losses induced by the modified rim seal design. Measurements at the rotor exit with the PCFs installed show a benefit in the total-to-total stage efficiency up to 0.4% for nominal and high rim seal purge flow rates. The work shows the potential to improve the aerodynamic efficiency by means of a well-designed rim seal exit geometry without losing the potential to block hot gas ingestion from the main annulus.
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Grigoriev, A. V., A. A. Kosmatov, О. A. Rudakov, and A. V. Solovieva. "Theory of gas turbine engine optimal gas generator." VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, no. 2 (July 2, 2019): 52–61. http://dx.doi.org/10.18287/2541-7533-2019-18-2-52-61.
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The article substantiates the necessity of designing an optimal gas generator of a gas turbine engine. The generator is to provide coordinated joint operation of its units: compressor, combustion chamber and compressor turbine with the purpose of reducing the period of development of new products, improving their fuel efficiency, providing operability of the blades of a high-temperature cooled compressor turbine and meeting all operational requirements related to the operation of the optimal combustion chamber including a wide range of stable combustion modes, high-altitude start at subzero air and fuel temperature conditions and prevention of the atmosphere pollution by toxic emissions. Methods of optimizing the parameters of coordinated joint operation of gas generator units are developed. These parameters include superficial flow velocities in the boundary interface cross sections between the compressor and the combustion chamber, as well as between the combustion chamber and the compressor turbine. The effective efficiency of the engine thermodynamic cycle is the optimization target function. The required depth of the turbine blades cooling is a functional constraint evaluated with account for calculations of irregularity and instability of the gas temperature field and the actual flow turbulence intensity at the blades’ inlet. We carried out theoretical analysis of the influence of various factors on the gas flow that causes changes in the flow total pressure in the channels of the gas generator gas dynamic model, i.e. changes in the efficiencies of its units. It is shown that the long period (about five years) of the engine final development time, is due to the necessity to perform expensive full-scale tests of prototypes, in particular, it is connected with an incoordinate assignment in designing the values of the flow superficial velocities in the boundary sections between the gas generator units. Designing of an optimal gas generator is only possible on the basis of an integral mathematical model of an optimal combustion chamber.
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Diakunchak, I. S. "Cold Flow Turbine Rig Tests of the Original and Redesigned Compressor Turbines of an Industrial Gas Turbine Engine." Journal of Turbomachinery 111, no. 2 (April 1, 1989): 146–52. http://dx.doi.org/10.1115/1.3262249.
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This paper describes the results of cold flow turbine rig tests carried out on the original and redesigned compressor turbines of an industrial gas turbine engine. Some details of the aerodynamic design of the latest variant, a brief description of the advanced technology design methods used in this design, and a description of the test facility are included. Bulk stage performance and detail rotor exit radial-circumferential traverse results are presented. These test results demonstrate that the design point stage efficiency of the redesigned compressor turbine is about six percentage points higher than that of the original design.
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Mai, Thanh Dam, and Jaiyoung Ryu. "Effects of Leading-Edge Modification in Damaged Rotor Blades on Aerodynamic Characteristics of High-Pressure Gas Turbine." Mathematics 8, no. 12 (December 9, 2020): 2191. http://dx.doi.org/10.3390/math8122191.
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The flow and heat-transfer attributes of gas turbines significantly affect the output power and overall efficiency of combined-cycle power plants. However, the high-temperature and high-pressure environment can damage the turbine blade surface, potentially resulting in failure of the power plant. Because of the elevated cost of replacing turbine blades, damaged blades are usually repaired through modification of their profile around the damage location. This study compared the effects of modifying various damage locations along the leading edge of a rotor blade on the performance of the gas turbine. We simulated five rotor blades—an undamaged blade (reference) and blades damaged on the pressure and suction sides at the top and middle. The Reynolds-averaged Navier–Stokes equation was used to investigate the compressible flow in a GE-E3 gas turbine. The results showed that the temperatures of the blade and vane surfaces with damages at the middle increased by about 0.8% and 1.2%, respectively. This causes a sudden increase in the heat transfer and thermal stress on the blade and vane surfaces, especially around the damage location. Compared with the reference case, modifications to the top-damaged blades produced a slight increase in efficiency about 2.6%, while those to the middle-damaged blades reduced the efficiency by approximately 2.2%.
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Rogalev, Andrey, Vladimir Kindra, Alexey Zonov, Nikolay Rogalev, and Levon Agamirov. "Evaluation of Bleed Flow Precooling Influence on the Efficiency of the E-MATIANT Cycle." Mechanics and Mechanical Engineering 22, no. 2 (August 24, 2020): 593–602. http://dx.doi.org/10.2478/mme-2018-0047.
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AbstractThis study aims to present a method for precooling bleed flow by water injection in the E-MATIANT cycle and to estimate its impact on the overall efficiency. The design parameters of the cycle are set up on the basis of the component technologies of today's state-of-the-art gas turbines with a turbine inlet temperature between 1100 and 1700°C. Several schemes of the E-MATIANT cycle are considered: with one, two and three combustion chambers. The optimal pressure ratio ranges for the considered turbine inlet temperatures are identified and a comparison with existing evaluations is made. For the optimal initial parameters, cycle net efficiency varies from 42.0 to 49.8%. A significant influence of turbine stage cooling model on optimal thermodynamic parameters and cycle efficiency is established. The maximum cycle efficiency is 44.0% considering cooling losses. The performance penalty due to the oxygen production and carbon dioxide capture is 20–22%.
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Dabbashi, Siddig, Tarak Assaleh, and Asia Gabassa. "EVALUATION OF DEGRADATION EFFECT ON INTERCOOLED GAS TURBINE PERFORMANCE OPERATED IN FLEXIBLE MODE." Scientific Journal of Applied Sciences of Sabratha University 2, no. 1 (April 25, 2019): 52–70. http://dx.doi.org/10.47891/sabujas.v2i1.52-70.
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This paper investigates the effect of type and level of degradation in industrial gas turbine components on its performance under flexible operation due to working as a back-up to renewable energy sources (RES). This investigation was carried out for a 2-shaft 100MW aero-derivative gas turbine with intercooler. Due to the influence of unpredictable nature of power produced by RES, power plants are now operating in a flexible manner, which will require the operator to either stop operation during high feed-in from renewables or reducing the power output from the power plant to a certain percentage. This in turn has an impact on the gas turbine performance and thermal efficiency, which is also affected by the type and level of degradation of their components compared to the non-degraded gas turbines. In-House performance simulation software (TURBOMATCH), which was developed in Cranfield University, was used to carry out gas turbine performance modelling according to daily flexible operation scenarios for all seasons. These daily operating scenarios, which describe the power settings and ambient conditions for a period of 24 hours, were developed from data obtained from the UK national grid and the meteorology office data base. Different levels of degradation in mass flow and efficiency for low-pressure compressor and high-pressure turbine were applied in this study. Results illustrate an obvious impact of degradation type and level on fuel flow, turbine entry temperature, blade cooling temperature, shaft rotational speed and thermal efficiency for different seasons. This study has resulted in a tool which may be useful to power plant operators in understanding the various operating scenarios according to the criteria they wish to choose.
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Schobeiri, M. T., and K. Pappu. "Optimization of Trailing Edge Ejection Mixing Losses: A Theoretical and Experimental Study." Journal of Fluids Engineering 121, no. 1 (March 1, 1999): 118–25. http://dx.doi.org/10.1115/1.2821991.
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The aerodynamic effects of trailing edge ejection on mixing losses downstream of cooled gas turbine blades were experimentally investigated and compared with an already existing one-dimensional theory by Schobeiri (1989). The significant parameters determining the mixing losses and, therefore, the efficiency of cooled blades, are the ejection velocity ratio, the cooling mass flow ratio, the temperature ratio, the slot thickness ratio, and the ejection flow angle. To cover a broad range of representative turbine blade geometry and flow deflections, a General Electric power generation gas turbine blade with a high flow deflection and a NASA-turbine blade with intermediate flow deflection and different thickness distributions were experimentally investigated and compared with the existing theory. Comprehensive experimental investigations show that for the ejection velocity ratio μ = 1, the trailing edge ejection reduces the mixing losses downstream of the cooled gas turbine blade to a minimum, which is in agreement with the theory. For the given cooling mass flow ratios that are dictated by the heat transfer requirements, optimum slot thickness to trailing edge thickness ratios are found, which correspond to the minimum mixing loss coefficients. The results allow the turbine aerodynamicist to minimize the mixing losses and to increase the efficiency of cooled gas turbine blades.
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Mrzljak, Vedran, Nikola Anđelić, Ivan Lorencin, and Zlatan Car. "Analysis of Gas Turbine Operation before and after Major Maintenance." Journal of Maritime & Transportation Science 57, no. 1 (December 2019): 57–70. http://dx.doi.org/10.18048/2019.57.04.
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This paper presents an analysis of the gas turbine real process (with all losses included) before and after a major maintenance. The analysis of both gas turbine operating regimes is based on data measured during its exploitation. Contrary to authors’ expectations, the major maintenance process did not result either in any decrease in losses or increase in efficiencies for the majority of the gas turbine components. However, the major maintenance influenced positively the gas turbine combustion chambers (reduction in losses and increase in the combustion chambers efficiency). After the major maintenance, the overall process efficiency decreased from 43.796% to 41.319% due to a significant decrease in the air mass flow rate and to an increase in the fuel mass flow rate in combustion chambers. A decrease in the gas turbine produced cumulative and useful power after a major maintenance also increased the specific fuel consumption.
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Filinov, Evgeny, Andrey Tkachenko, Hewa Hussein Omar, and Viktor Rybakov. "Increase the Efficiency of a Gas Turbine Unit for Gas Turbine Locomotives by Means of Steam Injection into the Flow Section." MATEC Web of Conferences 220 (2018): 03010. http://dx.doi.org/10.1051/matecconf/201822003010.
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In the modern world of railways, electrification is given great importance. Currently, more than 50% of all freight traffic carried out by electric traction. However, today, about half of the railways are not electrified, so it is necessary to use thermal engines to drive the locomotive. One of the possible variant is use gas turbine unit. The power of the gas turbine unit is given to the electric generator, and the electric motors drive the locomotive. In the present paper, as a power plant of a gas turbine locomotive, considered gas turbine unit with a twin -shaft gas generator of two schemes: 1- with steam supply to the inlet of the high-pressure turbine (into the combustion chamber) and 2- with steam supply to inlet of the free turbine. By CAE system of ASTRA, Collaboration operation lines calculated for different variants of steam injection. When the steam injected into the inlet of a free turbine and a high-pressure turbine. in the case of steam supply to the input of the free turbine and the high-pressure turbine there is a significant shift in Collaboration operation lines, which can lead to a decrease in the gas-dynamical stability of the compressors, and efficiency. To maintain the position of Collaboration operation lines, was applied the correction of the throughput capacity of free turbine nozzle vanes (by 15%). In the case of steam supply to the inlet of a free turbine, to ensure gas-dynamic stability of the compressors, a change in the throughput capacity of its nozzle vanes is required.
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Han, Je-Chin. "Recent Studies in Turbine Blade Cooling." International Journal of Rotating Machinery 10, no. 6 (2004): 443–57. http://dx.doi.org/10.1155/s1023621x04000442.
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Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. Developments in turbine cooling technology play a critical role in increasing the thermal efficiency and power output of advanced gas turbines. Gas turbine blades are cooled internally by passing the coolant through several rib-enhanced serpentine passages to remove heat conducted from the outside surface. External cooling of turbine blades by film cooling is achieved by injecting relatively cooler air from the internal coolant passages out of the blade surface in order to form a protective layer between the blade surface and hot gas-path flow. For internal cooling, this presentation focuses on the effect of rotation on rotor blade coolant passage heat transfer with rib turbulators and impinging jets. The computational flow and heat transfer results are also presented and compared to experimental data using the RANS method with various turbulence models such as k-ε, and second-moment closure models. This presentation includes unsteady high free-stream turbulence effects on film cooling performance with a discussion of detailed heat transfer coef- ficient and film-cooling effectiveness distributions for standard and shaped film-hole geometry using the newly developed transient liquid crystal image method.
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Sudadiyo, Sri, and Jupiter Sitorus Pane. "DESAIN AWAL TURBIN UAP TIPE AKSIAL UNTUK KONSEP RGTT30 BERPENDINGIN HELIUM." JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA 18, no. 2 (June 30, 2016): 65. http://dx.doi.org/10.17146/tdm.2016.18.2.2319.
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ABSTRAK DESAIN AWAL TURBIN UAP TIPE AKSIAL UNTUK KONSEP RGTT30 BERPENDINGIN HELIUM. Konsep reaktor daya nuklir yang dikembangkan merupakan jenis reaktor berpendingin gas dengan temperatur tinggi (RGTT). Gas yang digunakan untuk mendinginkan teras RGTT adalah helium. Konsep RGTT ini dapat menghasilkan daya termal 30 MWth sehingga dinamakan RGTT30. Temperatur helium mampu mencapai 700 °C ketika keluar dari teras RGTT30 dan digunakan untuk memanaskan air di dalam steam generator hingga mencapai temperatur 435 °C. Steam generator dihubungkan dengan turbin uap yang dikopel dengan generator listrik untuk membangkitkan daya 7,27 MWe. Uap yang keluar dari turbin dilewatkan kondensor untuk mencairkan uap menjadi air. Rangkaian komponen dari steam generator, turbin, dan kondensor dinamakan sistem turbin uap. Turbin terdiri dari sudu-sudu yang dimaksudkan untuk mengubah tenaga uap kedalam tenaga mekanis berupa putaran. Efisiensi turbin merupakan parameter yang harus diperhatikan dalam sistem turbin uap ini. Tujuan dari makalah ini adalah untuk mengusulkan sudu tipe aksial dan untuk menganalisa perbaikan efisiensi turbin. Metode yang digunakan yaitu aplikasi prinsip termodinamika yang berhubungan dengan konservasi energi dan massa. Perangkat lunak Cycle-Tempo dipakai untuk mendapatkan parameter termodinamika dan untuk mensimulasikan sistem turbin uap berbasis RGTT30. Pertama, dibuat skenario dalam simulasi sistem turbin uap untuk mengetahui efisiensi dan laju aliran massa uap yang diperoleh nilai optimal 87,52 % dan 8,759 kg/s pada putaran 3000 rpm. Kemudian, turbin uap diberi sudu tipe aksial dengan diameter tip 1580 mm dan panjang 150 mm. Hasil yang diperoleh adalah nilai efisiensi turbin uap naik menjadi 88,3 % pada putaran konstan (3000 rpm). Penambahan nilai efisiensi turbin sebesar 0,78 % menunjukkan peningkatan kinerja RGTT30 secara keseluruhan. Kata kunci: Tipe aksial, turbin uap, RGTT30 ABSTRACT PRELIMINARY DESIGN ON STEAM TURBINE OF AXIAL TYPE FOR HELIUM-COOLED RGTT30 CONCEPT. The concept of a nuclear power reactor, which evolves, is high temperature gas-cooled reactor type (HTGR). Gas that is used to cool the HTGR core, is helium. The HTGR concept used in this study can yield thermal power of 30 MWth so that named RGTT30. Helium temperature can reach 700 °C when come out from the RGTT30 core and it is used for heating the water within steam generator to achieve the temperature of 435 °C. The steam generator is connected to a steam turbine, which is coupled with an electricity generator, for generating electric power of 7.27 MWe. The steam that comes out from the turbine is flowed through condenser for changing the steam into water. The component train of steam generator, turbine, and condenser was given the name of steam turbine system. The turbine consists of blades that are intended to transform the steam power into mechanical power in the form of rotational speed. Turbine efficiency is a parameter that must be considered in this steam turbine system. The aims of this paper are to propose blade of axial type and to analyze the efficiency improvement of the turbine. The method used is the application of the thermodynamic principles associated with conservations of energy and mass. Cycle-Tempo software is used to obtain thermodynamic parameters and to simulate the steam turbine system based on RGTT30. Firstly, a scenario is created to model and simulate the steam turbine system for determining the efficiency and the mass flow rate of steam. The optimal values for the efficiency and the mass flow rates at the speed of 3000 rpm are 87.52 % and 8.759 kg/s, respectively. Then, the steam turbine was given the blade of axial type with a tip diameter of 1580 mm and a length of 150 mm. The results obtained are turbine efficiency increasing to 88.3% on constant speed (3000 rpm). Enhancement in the turbine efficiency value of 0.78% showed raising the overall performance of RGTT30. Keywords: Axial type, steam turbine, RGTT30
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Kurz, Rainer. "Parameter Optimization on Combined Gas Turbine-Fuel Cell Power Plants." Journal of Fuel Cell Science and Technology 2, no. 4 (March 28, 2005): 268–73. http://dx.doi.org/10.1115/1.2041669.
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A thermodynamic model for a gas turbine-fuel cell hybrid is created and described in the paper. The effects of gas turbine design parameters such as compressor pressure ratio, compressor efficiency, turbine efficiency, and mass flow are considered. The model allows to simulate the effects of fuel cell design parameters such as operating temperature, pressure, fuel utilization, and current density on the cycle efficiency. This paper discusses, based on a parametric study, optimum design parameters for a hybrid gas turbine. Because it is desirable to use existing gas turbine designs for the hybrids, the requirements for this hybridization are considered. Based on performance data for a typical 1600hp industrial single shaft gas turbine, a model to predict the off-design performance is developed. In the paper, two complementary studies are performed: The first study attempts to determine the range of cycle parameters that will lead to a reasonable cycle efficiency. Next, an existing gas turbine, that fits into the previously established range of parameters, will be studied in more detail. Conclusions from this paper include the feasibility of using existing gas turbine designs for the proposed cycle.
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Roy Yap, Mun, and Ting Wang. "Simulation of Producer Gas Fired Power Plants with Inlet Fog Cooling and Steam Injection." Journal of Engineering for Gas Turbines and Power 129, no. 3 (December 9, 2006): 637–47. http://dx.doi.org/10.1115/1.2718571.
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Biomass can be converted to energy via direct combustion or thermochemical conversion to liquid or gas fuels. This study focuses on burning producer gases derived from gasifying biomass wastes to produce power. Since the producer gases are usually of low calorific values (LCV), power plant performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for 5MWe power plants. The power plants considered include simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems using the producer gas with low calorific values at approximately 30% and 15% of the natural gas heating value (on a mass basis). The LCV fuels are shown to impose high compressor back pressure and produce increased power output due to increased fuel flow. Turbine nozzle throat area is adjusted to accommodate additional fuel flows to allow the compressor to operate within safety margin. The best performance occurs when the designed pressure ratio is maintained by widening nozzle openings, even though the turbine inlet pressure is reduced under this adjustment. Power augmentations under four different ambient conditions are calculated by employing gas turbine inlet fog cooling. Comparison between inlet fog cooling and steam injection using the same amount of water mass flow indicates that steam injection is less effective than inlet fog cooling in augmenting power output. Maximizing steam injection, at the expense of supplying the steam to the steam turbine, significantly reduces both the efficiency and the output power of the combined cycle. This study indicates that the performance of gas turbine and combined cycle systems fueled by the LCV fuels could be very different from the familiar behavior of natural gas fired systems. Care must be taken if on-shelf gas turbines are modified to burn LCV fuels.
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Norris, G., and R. G. Dominy. "Diffusion rate influences on inter-turbine diffusers." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 211, no. 3 (May 1, 1997): 235–42. http://dx.doi.org/10.1243/0957650971537141.
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Inter-turbine diffusers are becoming of increasing importance to the aero gas turbine designer to diffuse the flow between the HP (high-pressure) or IP (intermediate-pressure) turbine and the LP (low-pressure) turbine. Diffusing the flow upstream of the LP turbine and raising the mean passage radius increases stage efficiency. These inter-turbine diffusers, which have high curvature, S-shaped geometry and low-energy wakes created by the upstream turbine, together give rise to secondary flows, making the flow fully three-dimensional. Using both experimental measurements and CFD (computational fluid dynamics) predictions, this paper demonstrates how the secondary flow behaviour is controlled by both the duct diffusion rate and upstream wake intensity.
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Vlasic, E. P., S. Girgis, and S. H. Moustapha. "The Design and Performance of a High Work Research Turbine." Journal of Turbomachinery 118, no. 4 (October 1, 1996): 792–99. http://dx.doi.org/10.1115/1.2840936.
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This paper describes the design and performance of a high work single-stage research turbine with a pressure ratio of 5.0, a stage loading of 2.2, and cooled stator and rotor. Tests were carried out in a cold flow rig and as part of a gas generator facility. The performance of the turbine was assessed, through measurements of reaction, rotor exit conditions and efficiency, with and without airfoil cooling. The measured cooled efficiency in the cold rig was 79.9 percent, which, after correcting for temperature and measuring plane location, matched reasonably well the efficiency of 81.5 percent in the gas generator test. The effect of cooling, as measured in the cold rig, was to reduce the turbine efficiency by 2.1 percent. A part-load turbine map was obtained at 100, 110, and 118 percent design speed and at 3.9, 5.0, and 6.0 pressure ratio. The influence of speed and the limit load pattern for transonic turbines are discussed. The effect of the downstream measuring distance on the calculated efficiency was determined using three different locations. An efficiency drop of 3.2 percent was measured between the rotor trailing edge plane and a distance four chords downstream.
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Molyakov, V. D., B. A. Kunikeev, and N. I. Troitskiy. "Analysis of Physical Processes in the Flow Parts of Gas Turbines with Different Blade Chords." Proceedings of Higher Educational Institutions. Маchine Building, no. 7 (736) (July 2021): 40–53. http://dx.doi.org/10.18698/0536-1044-2021-7-40-53.
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Theoretical and experimental studies of the current flowing in the lattices of the turbine stage impeller with a change in the elongation of its blades at constant constraining diameters of the flow part (constant blade lengths) are carried out. Four single-stage turbines with different chords of rotor blades and their relative elongations have been investigated. To explain the nature of the integral characteristics of the turbine stage with a change in the relative elongation of the rotor blades, detailed studies of the spatial flow structure in the gap between wheels and behind the impeller were carried out. The peculiarity of the operation of four impellers in the turbine stage is shown when the geometry of the channels changes along the height of the flow path - from active at the root to highly reactive at the periphery. A characteristic redistribution of the local values of the efficiency and losses along the height of the lattices associated with a change in the elongation of the rotor blades and the rotation of the lattices has been revealed. It was found that with a decrease in the elongation of the rotor blades, the zone with the minimum efficiency moves from the root sections to the peripheral ones with its simultaneous restructuring and an increase in the minimum efficiency in this zone. In this case, the integral values of the efficiency of impellers with different relative elongations of the blades remain the same and sufficiently high.
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Yari, M., and K. Sarabchi. "Modelling and optimization of part-flow evaporative gas turbine cycles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 219, no. 7 (November 1, 2005): 533–48. http://dx.doi.org/10.1243/095765005x31315.
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The evaporative gas turbine cycle is a new high-efficiency power cycle that has reached the pilot plant testing stage. This article presents the construction of a mathematical model for thermodynamic simulation of part-flow evaporative gas turbine cycle including steam injection. The maximum deviation of predicted performance results by this model from available data in literature was 1 per cent. Then, changes in configuration of this cycle have been investigated. Configuration changes concern using feed water heater and injection of saturated vapour instead of superheated vapour to the humid air in the cycle. This investigation shows that both these strategies were in the direction of improvement of efficiency and specific work of cycles (intercooled and non-intercooled). The results obtained from this research show that using spray cooler as the intercooler in the intercooled cycle offers interesting perspectives. In addition, the optimization of part-flow evaporative gas turbine (PEvGT) cycles in the systematic manner is presented and discussed.
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Wilcock, R. C., J. B. Young, and J. H. Horlock. "The Effect of Turbine Blade Cooling on the Cycle Efficiency of Gas Turbine Power Cycles." Journal of Engineering for Gas Turbines and Power 127, no. 1 (January 1, 2005): 109–20. http://dx.doi.org/10.1115/1.1805549.
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A thermodynamic cycle analysis computer code for the performance prediction of cooled gas turbines has been used to calculate the efficiency of plants with varying combustor outlet temperature, compressor pressure ratio, and turbomachinery polytropic efficiency. It is shown that the polytropic efficiency exerts a major influence on the optimum operating point of cooled gas turbines: for moderate turbomachinery efficiency the search for enhanced combustor outlet temperature is shown to be logical, but for high turbomachinery efficiency this is not necessarily so. The sensitivity of the cycle efficiency to variation in the parameters determining the cooling flow rates is also examined. While increases in allowable blade metal temperature and film cooling effectiveness are more beneficial than improvements in other parameters, neither is as important as increase in turbomachinery aerodynamic efficiency.
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Hänni, Dominic, Rainer Schädler, Reza Abhari, Anestis Kalfas, Gregor Schmid, Ewald Lutum, and Nicolas Lecoq. "Purge flow effects on rotor hub endwall heat transfer with extended endwall contouring into the disk cavity." Journal of the Global Power and Propulsion Society 3 (May 13, 2019): 555–68. http://dx.doi.org/10.33737/jgpps/109838.
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Efficiency improvements for gas turbines are strongly coupled with increasing turbine inlet temperatures. This imposes new challenges for designers for efficient and adequate cooling of turbine components. Modern gas turbines inject bleed air from the compressor into the stator/rotor rim seal cavity to prevent hot gas ingestion from the main flow, while cooling the rotor disk. The purge flow interacts with the main flow field and static pressure field imposed by the turbine blades. This complex interaction causes non-uniform and jet-like penetration of the purge flow into the main flow field, hence affecting the endwall heat transfer on the rotor. To improve the understanding of purge flow effects on rotor hub endwall heat transfer, an unshrouded, high-pressure representative turbine design with 3D blading and extended endwall contouring of the rotor into the cavity seal was tested. The measurements were conducted in the 1.5-stage axial turbine facility LISA at ETH Zurich, where a state-of-the-art measurement setup with a high-speed infrared camera and thermally managed rotor insert was used to perform high-resolution heat transfer measurements on the rotor. Three different purge flow rates were investigated with regard to hub endwall heat transfer. Additionally, steady-state computational fluid dynamics simulations were performed to complement the experiments. It was found that the local heat transfer rate changes up to ±20% depending on the purge flow rate. The main part of the purged air is ejected at the endwall trough location and swept towards the rotor suction side, which is caused by the interaction of main flow and the cavity extended endwall design. The presence of low momentum purge flow locally reduces the heat transfer rate. Changes in adiabatic wall temperature and heat transfer (depending on purge rate) are observed from the platform start up to the cross passage migration of the secondary flow structures.
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Konovalov, Dmytro, Halina Kobalava, Mykola Radchenko, Ionut-Cristian Scurtu, and Roman Radchenko. "Determination of hydraulic resistance of the aerothermopressor for gas turbine cyclic air cooling." E3S Web of Conferences 180 (2020): 01012. http://dx.doi.org/10.1051/e3sconf/202018001012.
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One of the promising trends to increase the fuel and energy efficiency of gas turbines is contact cooling of cyclic air by using a twophase jet apparatus – an aerothermopressor. The rational parameters of work processes of the aerothermopressor were studied. The experimental setup was designed to simulate the aerothermopressor operation in the cooling air cycle of the gas turbine and to determine pressure losses in the aerothermopressor flow part. Based on the obtained experimental data, an empirical equation was proposed to determine the hydraulic resistance coefficient of the aerothermopressor flow part, depending on the initial pressure and the amount of water injected. The deviation of the calculated hydraulic resistance coefficient from the experimental ones is ± 25 %. The obtained results can be used in the practice of designing the aerothermopressor for gas turbine cyclic air cooling.
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Piskunov, Stanislav, Denis Popov, and Nikita Samoylenko. "Loss classification and review of secondary flow models in gas turbine cascades." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 63 (2020): 30–39. http://dx.doi.org/10.15593/2224-9982/2020.63.04.
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Much attention is paid to increasing the efficiency of turbofan engines by increasing the efficiency of the main modules. The aerodynamic efficiency of a turbine depends on the level of total pressure and kinetic energy losses, which are determined by the scale of secondary flows in the channels of the turbine cascades. There are many studies and articles on the topic of secondary flows, in which vortex structures are often given incorrect names. The problem lies in the absence of a unified model of secondary flows and mismatch in the names of the components of secondary flows in adaptation of model descriptions from English to Russian. The purpose of this review article is to consider the existing classifications of losses and the most famous models of secondary flows in turbine cascades, including the Wang model, the Goldstein and Spores model, the Sharma and Butler model, etc. The considered sources of information made it possible to single out the most complete classification of losses, compare with each other the components of secondary flows of various models, describe the mechanism of their occurrence and give the most complete nomenclature of secondary flows in turbine cascades.
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Kim, Kyoung Hoon, Kyoung Jin Kim, and Hyung Jong Ko. "Effects of Wet Compression on Performance of Regenerative Gas Turbine Cycle with Turbine Blade Cooling." Applied Mechanics and Materials 224 (November 2012): 256–59. http://dx.doi.org/10.4028/www.scientific.net/amm.224.256.
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When water is injected at an inlet of compressor, wet compression occurs due to evaporation of water droplets. In this work, the effects of wet compression on the performance of regenerative gas turbine cycle with turbine blade cooling are analytically investigated. For various pressure ratios and water injection ratios, the important system variables such as ratio of coolant flow for turbine blade cooling, fuel consumption, specific power and thermal efficiency are estimated. Parametric studies show that wet compression leads to significant enhancement in both specific power and thermal efficiency in gas turbine systems with turbine blade cooling.
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Mousafarash, Ali. "Exergy and Exergoenvironmental Analysis of a CCHP System Based on a Parallel Flow Double-Effect Absorption Chiller." International Journal of Chemical Engineering 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/2370305.
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A combined cooling, heating, and power (CCHP) system which produces electricity, heating, and cooling is modeled and analyzed. This system is comprised of a gas turbine, a heat recovery steam generator, and a double-effect absorption chiller. Exergy analysis is conducted to address the magnitude and the location of irreversibilities. In order to enhance understanding, a comprehensive parametric study is performed to see the effect of some major design parameters on the system performance. These design parameters are compressor pressure ratio, gas turbine inlet temperature, gas turbine isentropic efficiency, compressor isentropic efficiency, and temperature of absorption chiller generator inlet. The results show that exergy efficiency of the CCHP system is higher than the power generation system and the cogeneration system. In addition, the results indicate that when waste heat is utilized in the heat recovery steam generator, the greenhouse gasses are reduced when the fixed power output is generated. According to the parametric study results, an increase in compressor pressure ratio shows that the network output first increases and then decreases. Furthermore, an increase in gas turbine inlet temperature increases the system exergy efficiency, decreasing the total exergy destruction rate consequently.
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Verstraete, T., Z. Alsalihi, and R. A. Van den Braembussche. "Numerical Study of the Heat Transfer in Micro Gas Turbines." Journal of Turbomachinery 129, no. 4 (October 11, 2006): 835–41. http://dx.doi.org/10.1115/1.2720874.
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This paper presents a numerical investigation of the heat transfer inside a micro gas turbine and its impact on the performance. The large temperature difference between turbine and compressor in combination with the small dimensions results in a high heat transfer causing a drop in efficiency of both components. Present study aims to quantify this heat transfer and to reveal the different mechanisms that contribute to it. A conjugate heat transfer solver has been developed for this purpose. It combines a three-dimensional (3D) conduction calculation inside the rotor and the stator with a 3D flow calculation in the radial compressor, turbine and gap between stator and rotor. The results for micro gas turbines of different size and shape and different material characteristics are presented and the impact on performance is evaluated.
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Lee, Samuel P., Simon M. Barrans, and Ambrose K. Nickson. "The impact of volute aspect ratio and tilt on the performance of a mixed flow turbine." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 235, no. 6 (February 27, 2021): 1435–50. http://dx.doi.org/10.1177/0957650921998228.
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Current trends in the automotive industry towards engine downsizing means turbocharging now plays a vital role in engine performance. The purpose of turbocharging is to increase the engine inlet air density by utilising, the otherwise wasted energy in the exhaust gas. This energy extraction is commonly accomplished through the use of a radial turbine. Although less commonly used, mixed flow turbines can offer aerodynamic advantages due to the manipulation of blade leading (LE) angles, improving performance at low velocity ratios. The current paper investigates the performance of a mixed flow turbine with four volute designs, two radial and two tilted volutes each with one variant with an aspect ratio (AR)=0.5 and one with AR = 2. To ensure constant mass flow parameter (MFP) for aerodynamic similarity, volute area to radius ratio (A/r) was manipulated between the design variants. The maximum variation of cycle averaged normalized efficiency measured between the designs was 2.87%. Purely in the rotor region, the variation in normalized cycle averaged efficiency was 3%. The smallest volute AR designs showed substantial secondary flow development. The introduction of volute tilt further complicated the secondary flow development with the introduction of asymmetry to the flows. It was established that both AR and tilt have a notable effect on secondary flows, rotor inlet conditions and over all mixed flow turbine performance.
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Anand, A. K., C. S. Cook, J. C. Corman, and A. R. Smith. "New Technology Trends for Improved IGCC System Performance." Journal of Engineering for Gas Turbines and Power 118, no. 4 (October 1, 1996): 732–36. http://dx.doi.org/10.1115/1.2816988.
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The application of gas turbine technology to IGCC systems requires careful consideration of the degree and type of integration used during the system design phase. Although gas turbines provide the primary output and efficiency gains for IGCC systems, as compared with conventional coal-fired power generation systems, they are commercially available only in specific size ranges. Therefore, it is up to the IGCC system designer to optimize the IGCC power plant within the required output, efficiency, and site conditions by selecting the system configuration carefully, particularly for air separation unit (ASU) integration incorporated with oxygen blown gasification systems. An IGCC system, based on a generic, entrained flow, oxygen blown gasification system and a GE STAG 109FA combined cycle has been evaluated with varying degrees of ASU integration, two fuel equivalent heating values and two gas turbine firing temperatures to provide net plant output and efficiency results. The data presented illustrate the system flexibility afforded by variation of ASU integration and the potential performance gains available through the continued use of gas turbine advances. Emphasis is placed on system design choices that favor either low initial investment cost or low operating cost for a given IGCC system output.
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Moliere, Michel, Jean-Noël Jaubert, Romain Privat, and Thierry Schuhler. "Stationary gas turbines: an exergetic approach to part load operation." Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 75 (2020): 10. http://dx.doi.org/10.2516/ogst/2020001.
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As renewables are progressively displacing thermal plants in the power generation scene worldwide, the vocation of stationary Gas Turbines (GT) is deeply evolving. In this irreversible move GT plants are called upon to become cycling units with increasingly variable load profiles. This is dictated by the need to compensate for the fluctuations of renewable energy sources and secure the spinning reserve that is indispensable for the stability of the grids. This new scenario creates a serious challenge for gas turbine designers and operators in terms of investment policy, plant management and equipment lifetime. Indeed, operating a gas turbine at part, variable load requires reducing its firing temperature and possibly its air flow. While part load operation entails efficiency losses with respect to the full load mode, load variations cause maintenance penalties due the premature component ageing tied namely with thermal and low cycle fatigue effects on machine materials. As far as efficiency is concerned, an exergy analysis of a contemporary, air-based Brayton cycle is useful for quantifying and comparing the losses incurred by the various engine components. Such study reveals the high sensitivity of compressor efficiency to load decreases. Among possible counter-measures, heating the air at the compressor intake represents a simple mitigation measure, as it enables reducing the air flow rate while preserving to some extent the efficiency of the compressor and consequently GT efficiency.
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Khodak, E. A., and G. A. Romakhova. "Thermodynamic Analysis of Air-Cooled Gas Turbine Plants." Journal of Engineering for Gas Turbines and Power 123, no. 2 (August 1, 2000): 265–70. http://dx.doi.org/10.1115/1.1341204.
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At present high temperature, internally cooled gas turbines form the basis for the development of highly efficient plants for utility and industrial markets. Minimizing irreversibility of processes in all components of a gas turbine plant leads to greater plant efficiency. Turbine cooling, like all real processes, is an irreversible process and results in lost opportunity for producing work. Traditional tools based on the first and second laws of thermodynamics enable performance parameters of a plant to be evaluated, but they give no way of separating the losses due to cooling from the overall losses. This limitation arises from the fact that the two processes, expansion and cooling, go on simultaneously in the turbine. Part of the cooling losses are conventionally attributed to the turbine losses. This study was intended for the direct determination of lost work due to cooling. To this end, a cooled gas turbine plant has been treated as a work-producing thermodynamic system consisting of two systems that exchange heat with one another. The concepts of availability and exergy have been used in the analysis of such a system. The proposed approach is applicable to gas turbines with various types of cooling: open-air, closed-steam, and open-steam cooling. The open-air cooling technology has found the most wide application in current gas turbines. Using this type of cooling as an example, the potential of the developed method is shown. Losses and destructions of exergy in the conversion of the fuel exergy into work are illustrated by the exergy flow diagram.
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Hu, Bo, Xuesong Li, Yanxia Fu, Chunwei Gu, Xiaodong Ren, and Jiaxing Lu. "Axial Thrust, Disk Frictional Losses, and Heat Transfer in a Gas Turbine Disk Cavity." Energies 12, no. 15 (July 29, 2019): 2917. http://dx.doi.org/10.3390/en12152917.
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The gas turbine is a kind of high-power and high-performance energy machine. Currently, it is a hot issue to improve the efficiency of the gas turbines by reducing the amount of secondary air used in the disk cavity. The precondition is to understand the effects of the through-flow rate on the axial thrust, the disk frictional losses, and the characteristics of heat transfer under various experimental conditions. In this paper, experiments are conducted to analyze the characteristics of flow and heat transfer. To ensure the safe operation of the gas turbine, the pressure distribution and the axial thrust are measured for various experimental conditions. The axial thrust coefficient is found to decrease as the rotational speed and the through-flow rate increases. By torque measurements, the amounts of the moment coefficient drop as the rotational speed increases while increase with through-flow rate. In order to better analyze the temperature field within the cavity, both the local and the average Nusselt number are investigated with the help of thermochromic liquid crystal technique. Four correlations for the local Nusselt number are determined according to the amounts of a through-flow coefficient. The results in this study can help the designers to better design the secondary air system in a gas turbine.
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Heng, Wu, Li Benwei, Zhao Shufan, and Wang Yonghua. "Study on the Mechanism of a Carrier-based Engine Parts' Performance Decline and Its Impact on the Whole Engine Performance." MATEC Web of Conferences 179 (2018): 01012. http://dx.doi.org/10.1051/matecconf/201817901012.
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The technical approach "use – parts' change - engine performance change" has been adopted to study and analyse the gas unit parts' performance changes of an engine after a long time operation. The mechanism of performance decline of the turbine is analysed based on the numerical simulation, the impact of components' performance decline on overall engine performance is studied and the correlation analysis is carried out. The results show that the change of turbine tip clearance, roughness increase and surface change will lead to the enhancement of secondary flow and the increase of influence area, and the turbulence effect is strengthened, resulting in the decrease of turbine circulation capacity and efficiency. The booster ratio of high pressure compressor, the flow capacity of high pressure and low pressure turbines, the flow capacity and efficiency of fan are the major component parameters causing the overall engine performance's degradation. And it also provides theoretical basis for the prevention of engine performance's degradation and online washing of parts and the whole machine.
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El-Masri, M. A. "A Modified, High-Efficiency, Recuperated Gas Turbine Cycle." Journal of Engineering for Gas Turbines and Power 110, no. 2 (April 1, 1988): 233–42. http://dx.doi.org/10.1115/1.3240112.
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The thermal efficiency of an intercooled/recuperated cycle may be increased by: (a) evaporatively aftercooling the compressor discharge; and (b) injecting and evaporating an additional amount of water in the recuperator. Comparative computations of such a modified cycle and intercooled/recuperated cycles carried out over a wide range of pressure ratios and turbine inlet temperatures and at two different levels of component technologies show an advantage of over five percentage points in efficiency for the modified cycle. About 60 percent of this improvement results from modification (a) and 40 percent from modification (b). The modified intercooled/recuperated cycle is compared with nonintercooled steam-injected gas turbine systems at each component technology level. The present cycle is found to be superior by about 2.75 percentage points in efficiency and to require a substantially smaller water flow rate. To assist in interpreting those differences, the method of available-work analysis is introduced and applied. This is identical to exergy analysis for systems with a pure-substance working fluid, but differs from the latter for systems using a mixture of pure substances insofar as the thermodynamic dead state is defined for the chemical and phase composition realized at the exhaust conditions of practical engineering devices and systems. This analysis is applied to the heat-recovery processes in each of the three systems considered. It shows that the substantial, fundamental available-work loss incurred by mixing steam and gases in the steam-injected system is the main reason for the superior efficiency of the precent cycle.
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Rao, K. V. J., S. Kolla, Ch Penchalayya, M. Ananda Rao, and J. Srinivas. "Optimum stage design in axial-flow gas turbines." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 216, no. 6 (September 1, 2002): 433–45. http://dx.doi.org/10.1243/095765002761034203.
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This paper proposes the formulation and solution procedures in the stage optimization of the effective dimensions of an axial-flow gas turbine. Increasing the stage efficiency and minimizing the overall mass of components per stage are the common objectives in gas turbine design. This multiple objective function, with important constraints like natural frequency limits, root stress values, and tip deflection in blades, constitutes the overall optimization problem. The problem is solved by using a modified nonlinear simplex method with a built-in user interactive program that helps in on-line modifications of parameters other than variables in the problem. Results are presented with single objective and multiple objective criteria, including sensitivity analyses about the optimum point.
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Mankonen, Aleksi, Juha Kaikko, Esa Vakkilainen, and Vitaliy Sergeev. "Thermodynamic analysis of a condensing evaporator in an evaporative gas turbine cycle." MATEC Web of Conferences 245 (2018): 07007. http://dx.doi.org/10.1051/matecconf/201824507007.
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Low efficiency is the main stumbling block preventing the widespread adoption of small-scale gas turbines in distributed energy production. The evaporative gas turbine cycle has been proposed as a way to improve efficiency, but the large number of components required make the configuration complex and expensive. The condensing evaporator is a component that simplifies the evaporative gas turbine cycle. The heat and mass exchanger device is designed for an externally fired application, which means that the flue gas stream is replaced by moist air. The air-water mixture condenses inside a tube bank, releasing heat to the evaporating water film on the other side of the tubes. Similar inventions include the tubular humidifier and the Maisotsenko compressed air saturator, which also aim to make the evaporative gas turbine cycle more economically feasible. Available theory focuses on either humidification towers or evaporative condensers in HVAC applications. The tubular humidifier has been analyzed in a similar manner as humidification tower since the flow configurations of the two components are similar. However, the theory of humidification towers is not directly applicaple to the condensing evaporator. This study proposes a method of analysis of the condensing evaporator in power generation.
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Hoffren, J., T. Talonpoika, J. Larjola, and T. Siikonen. "Numerical Simulation of Real-Gas Flow in a Supersonic Turbine Nozzle Ring." Journal of Engineering for Gas Turbines and Power 124, no. 2 (March 26, 2002): 395–403. http://dx.doi.org/10.1115/1.1423320.
Full textAbstract:
In small Rankine cycle power plants, it is advantageous to use organic media as the working fluid. A low-cost single-stage turbine design together with the high molecular weight of the fluid leads to high Mach numbers in the turbine. Turbine efficiency can be improved significantly by using an iterative design procedure based on an accurate CFD simulation of the flow. For this purpose, an existing Navier-Stokes solver is tailored for real gas, because the expansion of an organic fluid cannot be described with ideal gas equations. The proposed simulation method is applied for the calculation of supersonic flow in a turbine stator. The main contribution of the paper is to demonstrate how a typical ideal-gas CFD code can be adapted for real gases in a very general, fast, and robust manner.
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Ameri, A. A., E. Steinthorsson, and D. L. Rigby. "Effect of Squealer Tip on Rotor Heat Transfer and Efficiency." Journal of Turbomachinery 120, no. 4 (October 1, 1998): 753–59. http://dx.doi.org/10.1115/1.2841786.
Full textAbstract:
Calculations were performed to simulate the tip flow and heat transfer on the GE-E3 first-stage turbine, which represents a modern gas turbine blade geometry. Cases considered were a smooth tip, 2 percent recess, and 3 percent recess. In addition, a two-dimensional cavity problem was calculated. Good agreement with experimental results was obtained for the cavity calculations, demonstrating that the k–ω turbulence model used is capable of representing flows of the present type. In the rotor calculations, two dominant flow structures were shown to exist within the recess. Also areas of large heat transfer rate were identified on the blade tip and the mechanisms of heat transfer enhancement were discussed. No significant difference in adiabatic efficiency was observed for the three tip treatments investigated.
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Schädler, Rainer, Dominic Hänni, Anestis Kalfas, Reza Abhari, Gregor Schmid, Ewald Lutum, and Carsten Schneider. "Noise characteristics of a reduced blade count rotor with improved stage efficiency." Journal of the Global Power and Propulsion Society 3 (November 18, 2019): 653–67. http://dx.doi.org/10.33737/jgpps/112303.
Full textAbstract:
A reduction in rotor blade count in combination with a gain in aerodynamic performance is a desirable design goal for gas turbines to reduce the overall operational costs. Reducing the number of blades provokes inherently an increase in blade loading which drives the secondary flow strength. In the presented experimental work, the results of inter-stage probe measurements in a highly loaded 1.5-stage axial turbine rig show the potential to improve the stage efficiency for a reduced blade count rotor with respect to a baseline configuration with more blades. Time-resolved probe measurements reveal the detrimental effects on the turbine tonal noise level. It is found that the periodic vorticity fluctuations induced by the interaction of the rotor passage secondary flow structures with the potential field of the downstream stator, leads at specific span positions to a strong increase in the noise level at rotor exit with respect to the baseline. Both, the downstream effect of the convected rotor flow structures as well as the periodic interaction of the second stator originated flow structures are found to drive the acoustic field of the turbine. Overall, the stage efficiency benefit achievement of 0.4% for a 22% reduction in rotor blade count is derogated by an increase in tonal noise by up to 13 dB at the second stator exit.
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Horlock, J. H. "The Evaporative Gas Turbine [EGT] Cycle." Journal of Engineering for Gas Turbines and Power 120, no. 2 (April 1, 1998): 336–43. http://dx.doi.org/10.1115/1.2818127.
Full textAbstract:
Humidification of the flow through a gas turbine has been proposed in a variety of forms. The STIG plant involves the generation of steam by the gas turbine exhaust in a heat recovery steam generator (HRSG), and its injection into or downstream of the combustion chamber. This increases the mass flow through the turbine and the power output from the plant, with a small increase in efficiency. In the evaporative gas turbine (or EGT) cycle, water is injected in the compressor discharge in a regenerative gas turbine cycle (a so-called CBTX plant—compressor [C], burner [B], turbine [T], heat exchanger [X]); the air is evaporatively cooled before it enters the heat exchanger. While the addition of water increases the turbine mass flow and power output, there is also apparent benefit in reducing the temperature drop in the exhaust stack. In one variation of the basic EGT cycle, water is also added downstream of the evaporative aftercooler, even continuously in the heat exchanger. There are several other variations on the basic cycle (e.g., the cascaded humidified advanced turbine [CHAT]). The present paper analyzes the performance of the EGT cycle. The basic thermodynamics are first discussed, and related to the cycle analysis of a dry regenerative gas turbine plant. Subsequently some detailed calculations of EGT cycles are presented. The main purpose of the work is to seek the optimum pressure ration in the EGT cycle for given constraints (e.g., fixed maximum to minimum temperature). It is argued that this optimum has a relatively low value.
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Choi, Myung Gon, and Jaiyoung Ryu. "Numerical Study of the Axial Gap and Hot Streak Effects on Thermal and Flow Characteristics in Two-Stage High Pressure Gas Turbine." Energies 11, no. 10 (October 4, 2018): 2654. http://dx.doi.org/10.3390/en11102654.
Full textAbstract:
Combined cycle power plants (CCPPs) are becoming more important as the global demand for electrical power increases. The power and efficiency of CCPPs are directly affected by the performance and thermal efficiency of the gas turbines. This study is the first unsteady numerical study that comprehensively considers axial gap (AG) in the first-stage stator and first-stage rotor (R1) and hot streaks in the combustor outlet throughout an entire two-stage turbine, as these factors affect the aerodynamic performance of the turbine. To resolve the three-dimensional unsteady-state compressible flow, an unsteady Reynolds-averaged Navier–Stokes (RANS) equation was used to calculate a k-ω SST γ turbulence model. The AG distance d was set as 80% (case 1) and 120% (case 3) for the design value case 2 (13 mm or d/Cs1 = 0.307) in a GE-E3 gas turbine model. Changes in the AG affect the overall flow field characteristics and efficiency. If AG decreases, the time-averaged maximum temperature and pressure of R1 exhibit differences of approximately 3 K and 400 Pa, respectively. In addition, the low-temperature zone around the hub and tip regions of R1 and second-stage rotor (R2) on the suction side becomes smaller owing to a secondary flow and the area-averaged surface temperature increases. The area-averaged heat flux of the blade surface increases by a maximum of 10.6% at the second-stage stator and 2.8% at R2 as the AG decreases. The total-to-total efficiencies of the overall turbine increase by 0.306% and 0.295% when the AG decreases.