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- Strand, Torsten, et al.
(författare)
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On the Significance of Concentrated Solar Power R&D in Sweden
- 2011
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Ingår i: Proceedings of the World Renewable Energy Congress 2011, Linköping.
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Konferensbidrag (refereegranskat)abstract
- Concentrated Solar Power (CSP) is an emerging renewable energy technology that has the potential to provide a major part of European energy needs at competitive cost levels. Swedish industry is strongly involved in CSP-based energy production either in the form of growing providers on the European energy market or as developers and producers of key components for CSP power plants. The growing industrial interest is reflected and accompanied by state of the art research in this field at the Department of Energy Technology at KTH. In the present paper the main challenges and opportunities for CSP R&D are presented and linked to the industrial environment and interests in Sweden. Related to these challenges, an overview of the latest research activities and results at the Department of Energy Technology is given with examples concerning CSP plant operation and optimisation, techno- economic cycle studies and high temperature solar receiver development.
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| 6. |
- Allégret-Bourdon, Davy, et al.
(författare)
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Study of shock movement and unsteady pressure on 2D generic model
- 2006
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Ingår i: Unsteady Aerodynamics, Aeroacoustics and Aeroelasticity of Turbomachines. - 1-4020-4267-1 ; s. 409-421
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Konferensbidrag (refereegranskat)abstract
- A flexible generic model has been developed at the Chair of Heat and Power Technology in order to perform fatter experiments in a more fundamental fashion. It is made of engineered flexible material and oscillate in a controlled way at non-uniform amplitude and variable frequencies. Time-resolved measurements of the unsteady surface pressures, the instantaneous model geometry as well as unsteady Schlieren visualizations are performed in order to study the shock wave motion and the aerodynamic load acting over this flexible generic bump. The model oscillates at reduced frequencies from 0.015 to 0.294 at transonic flow condition. The mode shapes of such a flexible bump strongly depends on the excitation frequency of the generic model. Schlieren pictures are obtained for an operating point characterized by an inlet Mach number of 0.63. Moreover, the presented results demonstrate that the phase of shock wave movement towards bump local motion shows a decreasing trend for the third bending mode shapes at reduced frequency higher than k=0.074. At the pressure taps located after the shock wave formation, the phase of pressure fluctuations towards bump local motion presents the same decreasing trend.
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| 7. |
- Andrinopoulos, Nikos, et al.
(författare)
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Design And Testing Of A Vibrating Test Object For Investigating Fluid-Structure Interaction
- 2008
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Ingår i: PROCEEDINGS OF THE ASME TURBO EXPO 2008, VOL 5, PT A. - NEW YORK : AMER SOC MECHANICAL ENGINEERS. - 978-0-7918-4315-4 ; s. 415-424
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Konferensbidrag (refereegranskat)abstract
- In this study the vibration properties of a deforming test object are presented. The test object is bump shaped and is integrated into the wall of a transonic wind tunnel. The purpose for using such a test object is to study, in a generic manner, the unsteady aerodynamic phenomena occurring due to the presence of a vibrating structure in the flow. The setup is part of an ongoing study to address the phenomena of fluid-structure interaction and shock-boundary layer interaction. The design objective for the test object is to assimilate a IF vibration mode at a given section of atypical compressor blade. Finite element (FE) analyses have been used to predict the frequency response of the test object prior to manufacturing. The design objectives have been verified experimentally by time-resolved laser measurements. It has been found that the FE predictions are in good agreement with experimental data. Furthermore it has been shown that the present test object allows for the achievement of the targeted vibration properties up to a frequency of 250Hz, corresponding to a reduced frequency above 0.8.
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| 8. |
- Baagherzadeh Hushmandi, Narmin, 1978-, et al.
(författare)
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Effects of multiblocking and axial gap distance on performance of partial admission turbines : A numerical analysis
- 2011
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Ingår i: Journal of turbomachinery. - 0889-504X. ; 133:3, s. 031028
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the effects of axial gap distance between the first stage stator and rotor blades and multiblocking on aerodynamics and performance of partial admission turbines are analyzed numerically. The selected test case is a two stage axial steam turbine with low reaction blades operating with compressed air. The multiblocking effect is studied by blocking the inlet annulus of the turbine in a single arc and in two opposing blocked arcs, each having the same admission degree. The effect of axial gap distance between the first stage stator and rotor blades is studied while varying the axial gap by 20% compared with the design gap distance. Finally, full admission turbine is modeled numerically for comparison. Performance of various computational cases showed that the first stage efficiency of the two stage partial admission turbine with double blockage was better than that of the single blockage turbine; however, the extra mixing losses of the double blockage turbine caused the efficiency to deteriorate in the downstream stage. It was shown that the two stage partial admission turbine with smaller axial gap than the design value had better efficiency of the first stage due to lower main flow and leakage flow interactions; however, the efficiency at the second stage decreased faster compared with the other cases. Numerical computations showed that the parameters, which increased the axial force of the first stage rotor wheel for the partial admission turbine, were longer blocked arc, single blocked arc, and reduced axial gap distance between the first stage stator and rotor blades.
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| 10. |
- Baagherzadeh Hushmandi, Narmin, et al.
(författare)
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Numerical Study of Unsteady Flow Phenomena in a Partial Admission Axial Steam Turbine
- 2008
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Ingår i: Proceedings of ASME Turbo EXPO 2008. - New York : AMER SOC MECHANICAL ENGINEERS. - 978-0-7918-4315-4 ; s. 713-722
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Konferensbidrag (refereegranskat)abstract
- This paper presents a numerical investigation of unsteady flow phenomena in a two-stage partial admission axial steam turbine. Results from unsteady three-dimensional computations are analyzed and compared with the available experimental data. Partial admission in the present study is introduced into the model by blocking only one segmental arc of the inlet guide vanes. Blocking only one segment (which corresponds to the experimental setup) makes the model unsymmetrical; therefore it is necessary to model the whole annulus of the turbine. The first stage rotor blades experience large static pressure change on their surface while passing the blocked channel. The effect of blockage on the rotor blades' surface pressure can be seen few passages around the blocked channel. Strong changes of the blades' surface pressure impose large unsteady forces on the blades of first stage rotor row.The circumferential static pressure plots at different cross sections along the domain indicate how the non-uniformity propagates in the domain. A peak pressure drop is seen at the cross section downstream of the first stage stator row. At further downstream cross sections, the static pressure becomes more evenly distributed. Entropy generation is higher behind the blockage due to the strong mixing and other loss mechanisms involved with partial admission. Analysis of the entropy plots at different cross sections indicates that the peak entropy moves in a tangential direction while traveling to the downstream stages. Comparisons of the unsteady three-dimensional numerical results and the experimental measurement data show good agreement in tendency. However some differences are seen in the absolute values especially behind the blockage.
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