scholarly journals Economy increase of turboset flow unit

2015 ◽  
Vol 2015 (4) ◽  
pp. 38-44
Author(s):  
Александр Осипов ◽  
Aleksandr Osipov ◽  
Алексей Дроконов ◽  
Aleksey Drokonov ◽  
Андрей Волженцов ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Turbine Rotor ◽  
Middle Part ◽  
The Body ◽  
Rotor Blades ◽  
Honeycomb Seal ◽  
Heat Leakage ◽  
Flow Part ◽  
Definition Of ◽  
Activity Decrease

At present time a considerable part of installed facilities of steam – and gasturbine units exhausted the body resources in connection with that their modernization is an urgent problem. The effectiveness increase in the work of a flow part in turbine units can be achieved at the expense of peripheral leakage decrease in bandless and banded stages of steam and gas turbines. In banded stages it can be achieved due to the choice of optimum value in the peripheral overlap of turbine rotor blades. In the BSTU there was obtained a dependence allowing the approximate definition of the optimum value for the overlap. At the same time the design of peripheral honeycomb seal with variable geometry allowing the operation with increased gaps in vibrating dangerous modes (start and stop) and in nominal conditions – with reduced gaps that gives the decrease of operation heat leakage about 30% in comparison with a basic design is offered. For bandless stages on the outer outline of an impeller the spiral profile groove manufacturing is of-fered for the effect of flow blocking at periphery. In the BSTU on the test air benches it was established that at the optimum angle of spiral profile groove slope equal to 150 to the plane of the impeller rotation the efficiency increment for the stage of an average fanning is equal to about 1% in comparison with the variant of a smooth overlap. For the purpose of stage operation reliability increase at economy conservation there is offered a creation of the hollow chamber with 2…3mm depth in the middle part of the blade exterior cross section. The application of variants developed for the flow part modernization in turbomachines should contribute to effectiveness and reliability increase of powergenerating units and ensure the ecological characteristics improvement in plants at the expense of their vibro-acoustic activity decrease.

scholarly journals Potential Applications of Structural Ceramic Composites in Gas Turbines

1990 ◽  
Author(s):  
W. P. Parks ◽  
R. R. Ramey ◽  
D. C. Rawlins ◽  
J. R. Price ◽  
M. Van Roode
Keyword(s):  
Gas Turbines ◽  
Ceramic Composite ◽  
Coal Gasification ◽  
Turbine Rotor ◽  
Ceramic Composites ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Structural Ceramic ◽  
Cycle Systems ◽  
Potential Applications

A Babcock and Wilcox - Solar Turbines Team has completed a program to assess the potential for structural ceramic composites in turbines for direct coal-fired or coal gasification environments. A review is made of the existing processes in direct coal firing, pressurized fluid bed combustors, and coal gasification combined cycle systems. Material requirements in these areas were also discussed. The program examined the state-of-the-art in ceramic composite materials. Utilization of ceramic composites in the turbine rotor blades and nozzle vanes would provide the most benefit. A research program designed to introduce ceramic composite components to these turbines was recommended.

Aerodynamic Design and Numerical Investigation on Overall Performance of a Micro Radial Turbine With Millimeter-Scale

2009 ◽  
Author(s):  
Lei Fu ◽  
Yan Shi ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Micro Gas Turbine ◽  
Radial Turbine ◽  
Overall Performance ◽  
Low Reynolds ◽  
Exit Mach Number ◽  
Installation Technology

For millimeter-scale microturbines, the principal challenge is to achieve a design scheme to meet the aerothermodynamics, geometry restriction, structural strength and component functionality requirements while in consideration of the applicable materials, realizable manufacturing and installation technology. This paper mainly presents numerical investigations on the aerothermodynamic design, geometrical design and overall performance prediction of a millimeter-scale radial turbine with rotor diameter of 10mm. Four kinds of turbine rotor profiles were designed, and they were compared with one another in order to select the suitable profile for the micro radial turbine. The leaving velocity loss in micro gas turbines was found to be a large source of inefficiency. The approach of refining the geometric structure of rotor blades and the profile of diffuser were adopted to reduce the exit Mach number thus improving the total-static efficiency. Different from general gas turbines, micro gas turbines are operated in low Reynolds numbers, 104∼105, which has significant effect on flow separation, heat transfer and laminar to turbulent flow transition. Based on the selected rotor profile, several micro gas turbine configurations with different tip clearances of 0.1mm, 0.2mm and 0.3mm, respectively; two different isothermal wall conditions; and two laminar-turbulent transition models were investigated to understand the particular influence of low Reynolds number. These influences on the overall performance of the micro gas turbine were analyzed in details. The results indicate that these configurations should be included and emphasized during the design process of the millimeter-scale micro radial turbines.

scholarly journals Experimental Investigation of Finite Aspect Ratio Cylindrical Bodies for Accelerated Wind Applications

Fluids ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 25 ◽  
Author(s):  
Michael Parker ◽  
Douglas Bohl
Keyword(s):  
Aspect Ratio ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Cylindrical Body ◽  
Turbine Rotor ◽  
Flow Speed ◽  
The Body ◽  
Rotor Blades ◽  
Wind Turbine Blades ◽  
Smooth Cylinder

The placement of a cylindrical body in a flow alters the velocity and pressure fields resulting in a local increase in the flow speed near the body. This interaction is of interest as wind turbine rotor blades could be placed in the area of increased wind speed to enhance energy harvesting. In this work the aerodynamic performance of two short aspect ratio (AR = 0.93) cylindrical bodies was evaluated for potential use in “accelerated wind” applications. The first cylinder was smooth with a constant diameter. The diameter of the second cylinder varied periodically along the span forming channels, or corrugations, where wind turbine blades could be placed. Experiments were performed for Reynolds numbers ranging from 1 × 105 to 9 × 105. Pressure distributions showed that the smooth cylinder had lower minimum pressure coefficients and delayed separation compared to the corrugated cylinder. Velocity profiles showed that the corrugated cylinder had lower peak speeds, a less uniform profile, and lower kinetic energy flux when compared to the smooth cylinder. It was concluded that the smooth cylinder had significantly better potential performance in accelerated wind applications than the corrugated cylinder.

Analysis of Physical Processes in the Flow Parts of Gas Turbines with Different Blade Chords

2021 ◽  
pp. 40-53
Author(s):  
V.D. Molyakov ◽  
B.A. Kunikeev ◽  
N.I. Troitskiy
Keyword(s):  
Flow Structure ◽  
Gas Turbines ◽  
Relative Elongation ◽  
Experimental Studies ◽  
Flow Path ◽  
Rotor Blades ◽  
Turbine Stage ◽  
Physical Processes ◽  
Integral Characteristics ◽  
Flow Part

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.

scholarly journals The KEMA Gas Turbines Target Project: Overview and Status

1995 ◽  
Author(s):  
R. A. Rooth
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Electricity Production ◽  
Combustion Chambers ◽  
Power Stations ◽  
Base Load ◽  
Production Industry

Recently, in the Netherlands a number of 11 combi blocks with prefitted gas turbines have been built. Additionally, there are preparations for five 335 MWe units at the Eems power station and plans for a further seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate that gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and who formulated and ordered the execution of the target project Gas turbines

scholarly journals User-Oriented Gas Turbine Research at KEMA

1996 ◽  
Author(s):  
R. A. Rooth
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
High Efficiency ◽  
Turbine Rotor ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Electricity Production ◽  
Combustion Chambers ◽  
Power Stations

In the 80’s and early 90’s, in the Netherlands 11 combi blocks with prefitted gas turbines have been built. This repowering programme increased the efficiency of the units involved by several percentage points. Additionally, the commissioning of the five 335 MWe units at the Eems power station is in progress and plans exist for a farther seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate mat gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, driven by the possibility of high-efficiency electricity generation in e.g. combined cycle units, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability, as will be shown under goals of the project. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and formulated the execution of the target project Gas Turbines.

Aerodynamic Design and Numerical Investigation on Overall Performance of a Microradial Turbine With Millimeter-Scale

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Lei Fu ◽  
Yan Shi ◽  
Qinghua Deng ◽  
Zhenping Feng
Keyword(s):  
Gas Turbines ◽  
Reynolds Numbers ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Low Reynolds Numbers ◽  
Overall Performance ◽  
Low Reynolds ◽  
Exit Mach Number ◽  
Rotor Profiles ◽  
Installation Technology

For millimeter-scale microturbines, the principal challenge is to achieve a design scheme to meet the aerothermodynamics, geometry restriction, structural strength, and component functionality requirements while in consideration of the applicable materials, realizable manufacturing, and installation technology. This paper mainly presents numerical investigations on the aerothermodynamic design, geometrical design, and overall performance prediction of a millimeter-scale radial turbine with a rotor diameter of 10 mm. Four kinds of turbine rotor profiles were designed, and they were compared with one another in order to select the suitable profile for the microradial turbine. The leaving velocity loss in microgas turbines was found to be a large source of inefficiency. The approach of refining the geometric structure of rotor blades and the profile of diffuser were adopted to reduce the exit Mach number, thus improving the total-static efficiency. Different from general gas turbines, microgas turbines are operated in low Reynolds numbers (104–105), which has significant effect on flow separation, heat transfer, and laminar to turbulent flow transition. Based on the selected rotor profile, several microgas turbine configurations with different tip clearances of 0.1 mm, 0.2 mm, and 0.3 mm, two different isothermal wall conditions, and two laminar-turbulent transition models were investigated to understand the particular influences of low Reynolds numbers. These influences on the overall performance of the microgas turbine were analyzed in detail. The results indicate that these configurations should be included and emphasized during the design process of the millimeter-scale microradial turbines.

Experimental Analysis of Dust Separation in the Internal Cooling Air System of Gas Turbines

2002 ◽  
Author(s):  
O. Schneider ◽  
H. J. Dohmen ◽  
A. W. Reichert
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Internal Cooling ◽  
Test Rig ◽  
Air System ◽  
And Performance ◽  
Cooling Air

For further improvements in efficiency and performance a better understanding of the internal cooling air system of gas turbines, which provides the turbine rotor blades with cooling air, is necessary. With the increase of cooling air passing through the internal air system, a greater amount of air borne particles are transported to the film cooling holes at the turbine blade surface. In spite of their small size, these holes are critical for blade cooling. Blockage of only a few holes could have harmful effects on the cooling film surrounding the blade. As a result, a reduced mean time between maintenance or even unexpected operation faults of the gas turbine during operation occurs. With a new test rig, the behaviour of particles in the internal cooling air system could be investigated at realistic flow conditions compared to a modern, real world gas turbine. It is possible to simulate different particle sizes and dust concentrations in the coolant air. A first comparison of design expectations and measurements, showing the behaviour of air borne particles in the internal cooling air system under realistic environmental conditions is given in the paper. Further the design tools for nearly a full internal air system flow path could be validated with this new test rig.

Potential Applications of Structural Ceramic Composites in Gas Turbines

1991 ◽  
Vol 113 (4) ◽  
pp. 628-634 ◽  
Author(s):  
W. P. Parks ◽  
R. R. Ramey ◽  
D. C. Rawlins ◽  
J. R. Price ◽  
M. Van Roode
Keyword(s):  
Gas Turbines ◽  
Ceramic Composite ◽  
Coal Gasification ◽  
Turbine Rotor ◽  
Ceramic Composites ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Structural Ceramic ◽  
Cycle Systems ◽  
Potential Applications

A Babcock and Wilcox-Solar Turbines Team has completed a program to assess the potential for structural ceramic composites in turbines for direct coal-fired or coal gasification environments. A review is made of the existing processes in direct coal firing, pressurized fluid bed combustors, and coal gasification combined cycle systems. Material requirements in these areas were also discussed. The program examined state-of-the-art ceramic composite materials. Utilization of ceramic composites in the turbine rotor blades and nozzle vanes would provide the most benefit. A research program designed to introduce ceramic composite components to these turbines was recommended.

Derrida on Pornography: Putting (It) Up for Sale

Derrida Today ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 97-114 ◽  
Author(s):  
Christopher Morris
Keyword(s):  
Cultural Studies ◽  
English Translation ◽  
The Body ◽  
The Past ◽  
French Original ◽  
Definition Of ◽  
Critical Discourses ◽  
Academic Debate

Over the past thirty years, academic debate over pornography in the discourses of feminism and cultural studies has foundered on questions of the performative and of the word's definition. In the polylogue of Droit de regards, pornography is defined as la mise en vente that is taking place in the act of exegesis in progress. (Wills's idiomatic English translation includes an ‘it’ that is absent in the French original). The definition in Droit de regards alludes to the word's etymology (writing by or about prostitutes) but leaves the referent of the ‘sale’ suspended. Pornography as la mise en vente boldly restates the necessary iterability of the sign and anticipates two of Derrida's late arguments: that there is no ‘the’ body and that performatives may be powerless. Deriving a definition of pornography from a truncated etymology exemplifies the prosthesis of origin and challenges other critical discourses to explain how pornography can be understood as anything more than ‘putting (it) up for sale’.

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