| 71. |
- Dayananda, Chathuri, et al.
(author)
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Constructive learning methodology for distant based online education in renewable energy technologies
- 2017
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In: PROCEEDINGS OF 2017 IEEE GLOBAL ENGINEERING EDUCATION CONFERENCE (EDUCON2017). - : IEEE. - 9781509054671 ; , s. 1033-1041
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Conference paper (peer-reviewed)abstract
- With the rising concerns about global warming, climate change and the rapid development in the renewable energy industry, many higher educational institutes such as engineering and technological schools around the world have started to offer various educational programs related to sustainable energy pedagogical topics. The knowledge of renewable energy will be a crucial part of scientific literacy for the future; hence it is an absolute necessity to develop easily accessible and flexible-learning approaches in order to succeed in this. Due to various factors, today, the digital online education concept is becoming very popular, both as blended on-campus and as stand-alone studies. Moreover, the traditional teacher driven education system is being also challenged and new student oriented teaching approaches are currently being identified and practiced by various educational experts. This paper discusses a case study developed by applying the learner-centered teaching concept and implemented as part of an online learning course offered for one month (14 hours of learning time was recommended per week) focusing on renewable energy technology innovations for five student groups in three countries. The methodology section of this paper discuss the application of aligned teaching methodology for designing and constructing the course, content deployment of an existing learning management tool and the implementation and course evaluation. Finally, the assessments were graded and results were analyzed to identify success of the new educational concept applied A survey questionnaire was also prepared to receive the thoughts about online learning courses and their experience with the online course performed From an overall point of view, the evaluation and the results exemplify the success and the acceptance of the offered online course by the participants providing good average grading and positive opinions of the method of implementation. Participants also expressed their greater enthusiasm and interest of participating in such online courses for renewable energy engineering, as many of the topics offered through the course are lacking in their existing or past study curriculums.
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| 72. |
- Demaziere, Christophe, 1973, et al.
(author)
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Open self-paced introductory course in nuclear engineering – How to guarantee student learning
- 2024
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In: Nuclear Engineering and Design. - 0029-5493. ; 417
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Journal article (peer-reviewed)abstract
- Ease of access to various free educational resources on the internet has often the disadvantage of resulting in scattered and fragmented knowledge and skills. Students “pick and choose” what they believe to be relevant for their learning but lack the necessary overview of the field to select those resources adequately and properly. This also applies to nuclear engineering, for which educational materials can be found on the web. Although some Massive Open Online Courses exist in this area, access to those often requires registration, or those courses are given during limited times. Following the Open Educational Resources initiative, there was thus a need to develop educational materials that are truly open and freely accessible to all, while guaranteeing student learning. This paper reports on efforts along those lines, which resulted in the planning, development, implementation and offering of three self-paced open course modules in nuclear engineering. Through a careful course design and use of the various features of a specific educator-to-educator Learning Management System, the students are guided through highly structured course materials capitalizing on a diversity of activities proposed to the students. Through self-assessment competence tests, the students can measure their mastery of the field, ultimately resulting in the delivery of a certificate of successful completion of the modules. This paper also presents, from a teacher’s perspective, some lessons learnt that could benefit other teachers interested in embarking on similar endeavours.
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| 73. |
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| 74. |
- El-Gabry, Lamyaa, et al.
(author)
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Measurements of Hub Flow Interaction on Film Cooled Nozzle Guide Vane in Transonic Annular Cascade
- 2015
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In: Journal of turbomachinery. - : ASME International. - 0889-504X .- 1528-8900. ; 137:8
-
Journal article (peer-reviewed)abstract
- An experimental study has been performed in a transonic annular sector cascade of nozzle guide vanes (NGVs) to investigate the aerodynamic performance and the interaction between hub film cooling and mainstream flow. The focus of the study is on the endwalls, specifically the interaction between the hub film cooling and the mainstream. Carbon dioxide (CO2) has been supplied to the coolant holes to serve as tracer gas. Measurements of CO2 concentration downstream of the vane trailing edge (TE) can be used to visualize the mixing of the coolant flow with the mainstream. Flow field measurements are performed in the downstream plane with a five-hole probe to characterize the aerodynamics in the vane. Results are presented for the fully cooled and partially cooled vane (only hub cooling) configurations. Data presented at the downstream plane include concentration contour, axial vorticity, velocity vectors, and yaw and pitch angles. From these investigations, secondary flow structures such as the horseshoe vortex, passage vortex, can be identified and show the cooling flow significantly impacts the secondary flow and downstream flow field. The results suggest that there is a region on the pressure side (PS) of the vane TE where the coolant concentrations are very low suggesting that the cooling air introduced at the platform upstream of the leading edge (LE) does not reach the PS endwall, potentially creating a local hotspot.
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| 75. |
- El-Gabry, Lamyaa, et al.
(author)
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Measurements of Hub Flow Interaction on Film Cooled Nozzle Guide Vane in Transonic Annular Cascade
- 2012
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In: Proceedings of the ASME Turbo Expo. - : ASME Press. - 9780791844748
-
Conference paper (peer-reviewed)abstract
- An experimental study has been performed in a transonic annular sector cascade of nozzle guide vanes to investigate the aerodynamic performance and the interaction between hub film cooling and mainstream flow. The focus of the study is on the endwalls, specifically the interaction between the hub film cooling and the mainstream. Carbon dioxide (CO2) has been supplied to the coolant holes to serve as tracer gas. Measurements of CO2 concentration downstream of the vane trailing edge can be used to visualize the mixing of the coolant flow with the mainstream.Flow field measurements are performed in the downstream plane with a 5-hole probe to characterize the aerodynamics in the vane. Results are presented for the fully cooled and partially cooled vane (only hub cooling) configurations. Data presented at the downstream plane include concentration contour, axial vorticity, velocity vectors, and yaw and pitch angles. From these investigations, secondary flow structures such as the horseshoe vortex, passage vortex, can be identified and show the cooling flow significantly impacts the secondary flow and downstream flow field. The results suggest that there is a region on the pressure side of the vane trailing edge where the coolant concentrations are very low suggesting that the cooling air introduced at the platform upstream of the leading edge does not reach the pressure side endwall, potentially creating a local hotspot.
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| 76. |
- Erlich, Catharina
(author)
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Comparative study of residue pellets from cane sugar and palm-oil industries with commercial wood pellets, applied in downdraft gasification
- 2009
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Doctoral thesis (other academic/artistic)abstract
- While biomass utilization for energy conversion in the industrialized nations is being largely developed, highly efficient and environmentally friendly, many tropical countries still use biomass at low efficiencies and high emission levels. The main reasons for these gaps are both political and technological: the energy markets are different, the Gross National Product (GDP) differs widely, and the feedstock differs in form and conversion behaviour. By implementing newer technologies adapted for tropical biomass feedstock, there would be a large potential in these countries for increased energy services since access to modern energy still is an essential step for improving the GDP for a country. Two dominant and tropically placed industries available for energy improvements are the cane sugar and palm-oil industries, which both produce an abundant amount of biomass residues. One step towards enhanced utilization of the residues, which would not require large investment costs in the power plant section nor in the processes of these industries, would be to install a pelletizing unit in the industry area to make fuel out of the excess residues for sale to the nearby villages. The pellets could be used both for cooking/heating and for small-scale power generation in a gasification-IC engine plant. The overall objective of this study is to experimentally evaluate the biomass residues in pellet form from the cane sugar and palm oil industries during conversion to useful energy in small-scale systems. The thesis is built upon five publications which include experimental analysis on flaming pyrolysis and rapid heating of pellets (paper I), pyrolysis in oxygen-free atmosphere and slow heating with subsequent steam gasification (paper II), global pelletizing data such as relative energy consumption, temperature levels, particle size and moisture content for successful pelletizing process (paper III), downdraft gasification evaluation including reactor temperature distribution, gas composition, cold-gas efficiency and packed-bed mechanics (paper IV) and a numerical model including the overall system efficiency for residue-to-electric power based in a small-scale gasifier system (paper V).The single-pellet studies revealed that pyrolysis in reducing atmosphere is to prefer compared to flaming pyrolysis in oxidizing environment with regards to the char quality. The studies also showed favourable thermochemical and mechanical behaviour for smaller size pellets (Ø6- Ø8mm) compared to larger size ones (Ø12 mm). Therefore, a downdraft gasifier of closed constricted type was designed for real gasification tests of the residue pellets of sizes Ø6- Ø8mm. These tests showed that all the studied pellet sorts could be used in one and the same gasifier, resulting in different reactor temperature distributions and gas compositions with lower heating values in the range of 4.1-5.4 MJ/m3n dry gas. The reactor bed dynamics showed to be dependent both on the fuel reactivity and the size, with less pressure drop for larger size pellets with lower reactivity. The pelletizing process itself revealed that the selected residues all needed higher moisture content and smaller particle size than recommended for wood for successful pelletizing. The relative electric energy consumption was lower when producing larger size pellets Ø8 mm than smaller ones (Ø6 mm) of same material. For untreated wet empty-fruit bunch (EFB) a stand-alone power plant with integrated EFB pre-treatment and gasification could generate 380 kWh of net electricity per ton of EFB at a “well-to-wheel” efficiency of 15%.
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| 77. |
- Erlich, Catharina, et al.
(author)
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Downdraft gasification of pellets made of wood, palm-oil residues respective bagasse: Experimental study
- 2011
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In: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 88:3, s. 899-908
-
Journal article (peer-reviewed)abstract
- The downdraft gasification technology has an increased interest among researchers worldwide due to the possibility to produce mechanical and electrical power from biomass in small-scale to an affordable price. The research is generally focused on improvement of the performance and optimizing of a certain gasifier, on testing different fuels, on increasing the user-friendliness of the gasifier and on finding other uses for the product gas than in an IC-engine, for example liquid fuel production.The main objective with the gasification tests presented here is to further contribute in the field by studying the impact of the char bed properties such as char bed porosity and pressure drop on the gasification performance as well as the impact of fuel particle size and composition on the gasification process in one and the same gasifier. In addition, there is very little gasification data available in literature of “before disregarded” fuels such as sugar cane bagasse from sugar/alcohol production and empty fruit bunch (EFB) from the palm-oil production. By pelletizing these residues, it is possible to introduce them into downdraft gasification technology which has been done in this study.The results show that one and the same reactor can be used for a variety of fuels in pellet form, but at varying air–fuel ratios, temperature levels, gas compositions and lower heating values. Gasification of wood pellets results in a richer producer gas while EFB pellets give a poorer one with higher contents of non-combustible compounds. In this gasification study, there is almost linear relation between the air–fuel ratio and the cold-gas efficiency for the studied fuels: Higher air–fuel ratios result in better efficiency. The pressure drop in the char bed is higher for more reactive fuels, which in turn is caused by low porosity char beds.
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| 78. |
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| 79. |
- Erlich, Catharina, et al.
(author)
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Pyrolysis and gasification of pellets from sugar cane bagasse and wood
- 2006
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In: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 85:10-11, s. 1535-1540
-
Journal article (peer-reviewed)abstract
- Wood pellets have become a popular form of biomass for power generation and residential heating due to easier handling both for transportation and for feeders in the treatment units, improved conversion and storage possibilities. The research on wood pellets as fuel has also been intensified during the past decade. However, other biomass sorts in pellet form, such as sugar cane bagasse, have not yet been extensively studied, especially not physical effects on the pellets during thermal treatment. Bagasse and wood pellets of different origin and sizes, shredded bagasse and wood chips have been studied in a thermogravimetric equipment to compare the effects of sort, origin, size and form of biomass during slow pyrolysis and steam gasification. Physical parameters such as decrease of volume and mass during treatment, as well as pyrolysis and gasification rates are of primary interest in the study. An important observation from the study is that for pellets the char density decreased during pyrolysis to a minimum around 450 degrees C, but thereafter increased with continued heating. The wood chips behaved differently with a continuous char density decrease during pyrolysis. Another conclusion from the work is that the size of the pellet has larger impact on the shrinkage behaviour throughout the conversion than the raw material, which the pellet is made of.
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| 80. |
- Erlich, Catharina, et al.
(author)
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Thermochemical characteristics of sugar cane bagasse pellets
- 2005
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In: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 84:5, s. 569-575
-
Journal article (peer-reviewed)abstract
- Pelletisation facilitates utilisation of sugar cane bagasse as a fuel and storage for year-round electricity generation. The present work determines thermochemical characteristics of bagasse pellets of different sizes and origins, using various temperatures (600, 750 and 900 degrees C) and gas flow rates (4, 7 and 10 L/min) with varying concentrations of oxygen (5, 10 and 15 %) in mixtures with nitrogen. Of major interest are the effects of raw material, origin and size of pellets, and the treatment conditions on the rate of pyrolysis and the structure and reactivity of char in combustion. The char yield of the larger pellets of high-ash content bagasse was practically independent of treatment conditions. Smaller pellets gave better mechanical stability of the char but lower reactivity.
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