| 1. |
- 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. - 9780791843154 ; , 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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| 2. |
- 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. - 9780791843154 ; , 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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| 5. |
- Udomsri, Seksan, et al.
(författare)
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Possibilities for Various Energy Applications from Municipal Solid Waste Incineration in Bangkok and Hanoi : Combined Heat, Cooling and Power Generation (CHCP) in Southeast Asia
- 2008
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Ingår i: Proceedings of i-CIPEC2008 - 5<sup>th</sup> International Conference on Combustion, Incineration/Pyrolysis and Emission Control. ; , s. 103-109
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Konferensbidrag (refereegranskat)abstract
- Increasingly intensive efforts are underway for employing renewable energy resources, especially when oil prices are unpredictable like today. Southeast Asia, which features large populations and expansive economies, already has a high energy demand and will grow even more in the future. Biomass is an important renewable energy source in this region, and Municipal Solid Waste (MSW) is an excellent candidate in this context. With industrialization, there has been an increase in the amount of MSW, particularly in large cities like Bangkok and Hanoi. While the need for a complete sustainable energy solution is crucial, solid waste management is also critical for these cities. Energy recovery from flue gases in thermal treatment plants is an integral part of MSW management for many industrialized nations. Often cogeneration can be employed for both enhancing the plant profitability and increasing the overall energy yield. However, it is normally difficult to justify traditional cogeneration in tropical locations since there is little need for the heat produced. The implementation of heat-driven cooling processes like absorption chillers is extremely attractive in this setting. In this paper, the energy applications from MSW in tropical urban areas have been investigated. Also investigated are the opportunities and potentials for various types of MSW power plants for providing both electricity and cooling in an innovative fashion. Results show that there is significant potential for various energy applications i.e. electricity, heatingand cooling from MSW in Southeast Asia. For example, electricity production via conventional incineration of MSW can achieve up to 2TWh per year in Bangkok and nearly this same amount in Hanoi. For heat-driven cooling, absorption chillers provide significant potential to replace electrically driven cooling: such systems are capable of providing 77 MWcooling and 22 MWel from CHP plant using MSW incineration. Heat driven chillers are also capable of reducing the fuel consumption per unit of cooling in comparison with conventional cooling technology: absorption chillers consume 0.78 MWfuel/MWcooling while distributed compression chillersconsume 2.06 MWfuel/MWcooling. If an MSW power plant coupled with heat- driven cooling is to be implemented, the system can save 118 MW of NG (60 MW of electricity) from thermal power plant.
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| 6. |
- Udomsri, Seksan, et al.
(författare)
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The Role of Municipal Solid Waste Incineration for Greenhouse Gas Mitigation : Towards Sustainable Energy Systems in Southeast Asia
- 2008
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Ingår i: Proceedings of SIDA Conference and Workshop in Uppsala - Meeting Global Challenges in Research Cooperation. - 9789197574198 ; , s. 60-67
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Konferensbidrag (refereegranskat)abstract
- This paper presents an evaluation of the potential of municipal solid waste incinerationfor greenhouse gas mitigation and promotion of biomass-based electricity productionin a more sustainable direction in Southeast Asia. Beyond political and environmentalpressures, renewable energy sources are inherently attractive and have become a globalconcern. Resource constraints and rapid growth in world energy demand have alreadybrought oil prices over record levels. Developing countries – especially in high economicgrowth regions of Southeast Asia – often have strained resources and suffer as a result.Enhanced energy security and renewable energy development is high on the publicagenda in Thailand and other countries in Asia. Biomass and municipal solid waste(MSW) have widely been accepted as important renewable energy sources because theymay be used as carbon dioxide (CO2) mitigation concepts. Solid waste management hasbecome a crucial issue in Southeast Asia since the most popular form for waste disposalstill employs open dumping. The overall objective of this investigation is to promotesound MSW management practices including waste-to-energy (WTE) recovery, as wellas to promote an expansion of biomass-based electricity. The energy recovery potentialof MSW is analyzed by investigating various types of incineration technologies. Bothconventional and more advanced hybrid dual-fuel cycles are considered to evaluate cycleperformance (electrical efficiency), CO2 emission and economic aspects. Results show that there is significant potential for environmental and waste management improvements viaMSW incineration. In Bangkok only, power production via hybrid power plants employingintegrated natural gas-fired topping cycles can achieve up to 4 TWh and 10 TWhin 2008 and 2030, respectively. The reduction of CO2 emissions is even more attractivewhen hybrid dual-fuel cycles are combined. CO2 reductions of 670 and 1,800 thousandtons, respectively, can be met in comparison with current thermal power plants. Hybriddual-fuel cycle is somewhat more attractive as it has quite short payback period (5 years)in terms of economy comparison.
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| 8. |
- Vogt, Damian, et al.
(författare)
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CHARACTERIZATION AND FIRST APPLICATION OF A THIN-FILM ELECTRET UNSTEADY PRESSURE MEASUREMENT TECHNIQUE
- 2008
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Ingår i: XIX Biannual Symposium on Measuring Techniques in Turbomachinery. - Brussels : Von Karman Institute for Fluid Dynamics. ; , s. 1-5
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new thin-film electret unsteady pressure measurement technique for application in turbomachine aerodynamical experiments is under investigation. The technique is based on a layered sensor comprising a permanently polarized foil in the center. Changes in foil thickness due to variation in pressure result in a potential difference, which is used as measurement signal. The investigated technique presents a cost attractive alternative for unsteady pressure measurement instrumentation. Low signal levels however put severe requirements to acquisition and the treatment of the signals, especially when reducing the sensor area. First measurements have been performed with a 2.5x2.5mm sensor. The signals have been correlated to Kulite data and good agreement has been found. A characterization of the technique as well a description of the first tests in relevant flow is presented in the paper.
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