| 1. |
- Aslanidou, Ioanna, et al.
(författare)
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Teaching gas turbine technology to undergraduate students in Sweden
- 2018
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Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791851128
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the teaching of gas turbine technology in a third-year undergraduate course in Sweden and the challenges encountered. The improvements noted in the reaction of the students and the achievement of the learning outcomes is discussed. The course, aimed at students with a broad academic education on energy, is focused on gas turbines, covering topics from cycle studies and performance calculations to detailed design of turbomachinery components. It also includes economic aspects during the operation of heat and power generation systems and addresses combined cycles as well as hybrid energy systems with fuel cells. The course structure comprises lectures from academics and industrial experts, study visits, and a comprehensive assignment. With the inclusion of all of these aspects in the course, the students find it rewarding despite the significant challenges encountered. An important contribution to the education of the students is giving them the chance, stimulation, and support to complete an assignment on gas turbine design. Particular attention is given on striking a balance between helping them find the solution to the design problem and encouraging them to think on their own. Feedback received from the students highlighted some of the challenges and has given directions for improvements in the structure of the course, particularly with regards to the course assignment. This year, an application developed for a mobile phone in the Aristotle University of Thessaloniki for the calculation of engine performance will be introduced in the course. The app will have a supporting role during discussions and presentations in the classroom and help the students better understand gas turbine operation. This is also expected to reduce the workload of the students for the assignment and spike their interest.
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| 2. |
- Efstathiadis, T., et al.
(författare)
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Geometry Optimization of Power Production Turbine For A Low Enthalpy (<= 100 degrees C) ORC System
- 2015
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 1624-1630
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Tidskriftsartikel (refereegranskat)abstract
- The present paper is examining the geometry optimization of a power production turbine, in the range of 100kW(el), for a low enthalpy Organic Rankine cycle system (<= 100 degrees C). In the last years, accelerated consumption of fossil fuels has caused many serious environmental problems such as global warming, ozone layer destruction and atmospheric pollution. It is this reason that a growing trend towards exploiting low-enthalpy content energy sources has commenced and led to a renewed interest in small-scale turbines for Organic Rankine Cycle applications. The design concept for such turbines can be quite different from either standard gas or steam turbine designs. The limited enthalpic content of many energy sources imposes the use of organic working media, with unusual properties for the turbine. A versatile cycle design and optimization requires the parameterization of the main turbine design. There are many potential applications of this power-generating turbine, including geothermal and concentrate solar thermal fields or waste heat of steam turbine exhausts. An integrated model of equations has been developed, thus creating a model to assess the performance of an organic cycle for various working fluids such as R134a and isobutane-isopentane mixture. The most appropriate working fluid has been chosen, taking its influence on both cycle efficiency and the specific volume ratio into consideration. This choice is of particular importance at turbine extreme operating conditions, which are strongly related to the turbine size. In order to assess the influence of various design parameters, a turbine design tool has been developed and applied to define the geometry of blades in a preliminary stage. Finally, as far as the working fluid is concerned, the mixture of 85% isopentane-15% isobutane has been chosen as the most suitable fluid for the low enthalpy ORC system, since its output net power is 10% higher compared to the output net power of R134a.
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| 3. |
- Gkoutzamanis, V. G., et al.
(författare)
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Thermal energy storage in combined cycle power plants : Comparing finite volume to finite element methods
- 2019
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Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2267-1242.
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Konferensbidrag (refereegranskat)abstract
- The research in thermal energy storage (TES) systems has a long track record. However, there are several technical challenges that need to be overcome, to become omnipresent and reach their full potential. These include performance, physical size, weight and dynamic response. In many cases, it is also necessary to be able to achieve the foregoing at greater and greater scale, in terms of power and energy. One of the applications in which these challenges prevail is in the integration of a thermal energy storage with the gas turbine (GT) compressor inlet conditioning system in a combined cycle power plant. The system is intended to provide either GT cooling or heating, based on the operational strategy of the plant. As a contribution to tackle the preceding, this article describes a series of 3-dimensional (3D) numerical simulations, employing different Computational Fluid Dynamics (CFD) methods, to study the transient effects of inlet temperature and flow rate variation on the performance of an encapsulated TES with phase change materials (PCM). A sensitivity analysis is performed where the heat transfer fluid (HTF) temperature varies from -7°C to 20°C depending on the operating mode of the TES (charging or discharging). The flow rate ranges from 50% to 200% of the nominal inflow rate. Results show that all examined cases lead to instant thermal power above 100kWth. Moreover, increasing the flow rate leads to faster solidification and melting. The increment in each process depends on the driving temperature difference between the encapsulated PCM and the HTF inlet temperature. Lastly, the effect of the inlet temperature has a larger effect as compared to the mass flow rate on the efficiency of the heat transfer of the system.
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| 4. |
- Pontika, E. C., et al.
(författare)
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Aeroengines : Multi-platform application for aero engine simulation and compressor map operating point prediction
- 2019
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Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791858677
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Konferensbidrag (refereegranskat)abstract
- This paper presents the development of AeroEngineS (Aircraft Engine Simulation), a multi-platform app with graphical user interface for aero engine simulation and compressor map operating point prediction. Gas turbine performance simulation is a crucial part of the design process. It provides information about the required operating conditions of all the components and the overall performance of the engine so that engineers can determine whether the current engine configuration meets the performance requirements. Some gas turbine simulation programs have been developed in the last decades, however, there was a lack of an open-source, lightweight, user-friendly, but still very accurate, application which would be easily accessible from all platforms. AeroEngineS can be used as a user-friendly preliminary design tool, since, during this design phase, details about the geometry are not known yet. The main aim is to calculate simply and quickly the basic parameters of the thermodynamic cycle and the performance, in order to determine which design is able to meet the required specifications. AeroEngineS constitutes a free and simple app which can primarily serve educational purposes as it is easily accessible by students from any platform to assist them in aero engine technology courses. Secondarily, it has the potential to be used even by engineers as a quick tool accessible from all devices. The app consists of two basic stand-alone functions. The first function is aero engine simulation at Design Point which solves thermodynamic calculations. The second function is compressor map operating point prediction using a novel method of combining scaling techniques and Artificial Neural Networks.
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