| 1. |
- Bengtsson, Selma, 1984, et al.
(författare)
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Criteria for Future Marine Fuels
- 2012
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Ingår i: The IAME 2012 Conference September 2012.
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Konferensbidrag (refereegranskat)
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| 2. |
- Svensson, Magnus, et al.
(författare)
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The development and certification of a single fuel high speed marine CI engine on methanol
- 2023
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Konferensbidrag (refereegranskat)abstract
- Reducing emissions is a priority for all vessels, as global warming is accelerating, and emissionregulations are becoming ever stricter. Still, waterborne transport is the most energy efficientalternative in many cases, and in some cases the only alternative. Vessels in the maritime sectoroperate far from electric charging infrastructure, and have large demands in terms of autonomy, so tobe able to carry an energy dense fuel onboard is required. With most of the maritime sector using fossil diesel to fuel compression ignition engines, significantamounts of greenhouse gases and harmful emissions are produced. Methanol is a clean burning fuel,meaning that no or very few harmful emissions are formed in the combustion. It also has attractiveproperties for onboard storage and can be produced from a renewable feedstock, which means a netzero CO2 fuel. FASTWATER is a European Horizon 2020 project that is looking to demonstrate and developmethanol as a fuel for medium and high-speed engines, with retrofit solutions and next generationsystems. One of the developments is that of a high speed, heavy duty single fuel compression ignitionengine. The compression ignited methanol engine allows the high efficiency from a diesel engine, incombination with the low emissions from a clean burning fuel. This paper presents the development of a demo single fuel compression ignition engine, using asingle fuel consisting primarily of methanol, with 3% ignition enhancer and lubricity additive. Theresults from emission tests are reported, with the engine having been certified according to IMO Tier 3legislation, the strictest marine emission standard today, without the need for emission aftertreatmentsystems. The engine is currently running in real world conditions in the pilot boat Pilot 120SEoperating at the east coast of Sweden.
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| 3. |
- Tillig, Fabian, 1984, et al.
(författare)
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A generic energy systems model for efficient ship design and operation
- 2017
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Ingår i: Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment. - : SAGE Publications. - 2041-3084 .- 1475-0902. ; 231:2, s. 649-666
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Tidskriftsartikel (refereegranskat)abstract
- There is an evironmental and econimical motivated need to reduce the fuel consumption and air emmissions of ships. To achieve a reduction of the energy consumption, the energy flow in the entire energy system of a ship must be analyzed in both, the component, or subsystem level as well as in a holistic way to capture the interactions between the components. Of the currently available energy consumption monitoring and prediction methods or models, no single model or method can be used to asses the energy efficiency of an arbritary vessel in both the early design phase and operation of ships. This study presents a new generic ship energy systems model that can be used for this purpose. This new model has two parts: one for assessment of a ship’s energy consumption based on an ordinary static power prediction and one for advanced operational analysis, considering hydrodynamic and machinery systems effects. A Panamax tanker vessel was used as the case study vessel to prove the versatility of the model for five example simulations for the design and operation of ships. The examples include variations of the main dimensions, propeller design, engine layout and the operational profile on a North Atlantic route. From the results, different areas with a potential for energy savings were identified.
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| 4. |
- Tillig, Fabian, 1984, et al.
(författare)
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Analysis of the reduction of uncertainties in the prediction of ships’ fuel consumption – from early design to operation conditions
- 2017
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Ingår i: Proceedings of The 2nd International Conference on Ships and Offshore Structures (ICSOS 2017). ; , s. 4-19
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Konferensbidrag (refereegranskat)abstract
- This investigation presents an approach that contributes to better understanding of achievable accuracy of fuel consumption predictions of ships and provides an example of how a thorough uncertainty analysis of prediction models can be performed. A generic ship energy systems model is used for the fuel consumption prediction of two reference ships: a RoRo ship and a tanker. The study presents how model and design uncertainties can be categorized and handled in four different phases of a ship’s life – from early design to ship operation. Monte Carlo simulations are carried out for two conditions (calm water and operation at sea) to calculate the mean (expected value) and uncertainty (standard deviation) of the fuel consumption. The results show that the uncertainty in the fuel consumption prediction in a very early phase of the design process is approximately 12%, whereas at a very late phase, it reduces to less than 4%. Finally, the simulation model and the approach to predict the fuel consumption presented in the study are applied to a real ship during operation conditions to demonstrate its features for a real case.
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| 5. |
- Tillig, Fabian, 1984, et al.
(författare)
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Analysis of uncertainties in the prediction of ships’ fuel consumption – from early design to operation conditions
- 2018
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Ingår i: Ships and Offshore Structures. - : Informa UK Limited. - 1754-212X .- 1744-5302. ; 13, s. 13-24
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Tidskriftsartikel (refereegranskat)abstract
- This investigation presents an approach that contributes to a better understanding of achievable accuracy of fuel consumption predictions of ships and provides an example of how a thorough uncertainty analysis of prediction models can be performed. A generic ship energy systems model is used for the fuel consumption prediction of two reference ships: a RoRo ship and a tanker. The study presents how method and design uncertainties can be categorized and handled in four different phases of a ship’s life – from early design to ship operation. Monte Carlo simulations are carried out for two conditions (calm water and operation at sea) to calculate the mean (expected value) and uncertainty (standard deviation) of the fuel consumption. The results show that the uncertainty in the fuel consumption prediction in a very early phase of the design process is approximately 12%, whereas at a very late phase, it reduces to less than 4%. Finally, the simulation model and the approach to predict the fuel consumption presented in the study are applied to a real ship during operation conditions to demonstrate its features for a real case.
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| 6. |
- Tillig, Fabian, 1984, et al.
(författare)
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Holistic ship energy systems modelling for efficient ship design and operation
- 2015
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Ingår i: Proceedings of The RINA International Conference on Energy Efficient Ships. - 1909024473 ; , s. 7-16
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Konferensbidrag (refereegranskat)abstract
- An introduction to and an overview of the state-of-the-art of energy systems models of ships is presented. An example of a generic, holistic and dynamic energy systems model is introduced and its components and their interactions are discussed. Examples from different stages of a ship’s lifecycle, from main dimension variation to speed profile improvements, are shown. Employing the results from these examples, it is discussed how this type of model can help solving the challenge of finding suitable design targets with respect to energy-efficient ship design and operation.
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| 7. |
- Willstrand, Ola, et al.
(författare)
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Lätta elfartyg – Electric Light : Lightweight and electrically propelled Ro-Pax ships
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this project was to establish an innovative ship concept for a fully electric Ro-Pax ship, which makes use of new technology, especially in the area of electrical propulsion and energy storage. The project also included a risk assessment of the concept and identification of possible follow-up studies of critical design items. There is a growing demand for all types of shipping to reduce their emissions of greenhouse gases and particles, and also NOx and SOx. Meeting IMO’s emissions objective by 2050 will require large efforts both for energy efficiency measures on existing ships and for new concepts for fossil-free ships. Electrical propulsion for small ships has been discussed for long and many installations are today operational. This project is an innovation project with participation from industrial partners contributing to the overall goal of sustainable shipping by proposing a ship concept for an electrically powered large Ro-Pax ship for shorter international voyage. The amount of electric energy estimated to be stored in batteries onboard is approximately 60 MWh. This is ten times more than the current largest marine battery installation. When it comes to fire safety, it is very important with a holistic approach, including integrity, ventilation, failure detection and fire suppression methods, etc., based on hazard identification. The battery fire safety concept developed in this project constitutes safety requirements guidelines for large ship battery installations and is one of the main results from the conducted risk analysis work. The idea of the presented concept is that it should be applicable for any electrically powered ship and that it could be used as starting point for discussions on IMO harmonized regulations for battery energy storage systems onboard ships. It can be concluded that a fully electric Ro-Pax ship operating on the route Gothenburg to Frederikshavn is a technically and commercially realistic alternative.
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| 8. |
- Zhu, Heng, 1995, et al.
(författare)
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Development and performance analysis of a crescent-type sail for WASP applications
- 2023
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Ingår i: Proceedings of Shipping, Sustainability & Solutions 2023. ; , s. 1-18
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Konferensbidrag (refereegranskat)abstract
- Wind-assisted or pure wind propulsion surely is one of the most promising options to radically reduce carbon emissions from shipping, already today. This study presents the design and evaluation process of a crescent-type sail, from CFD computations towards system-based performance predictions in real-life conditions. CFD computations are used to evaluate the performance of different sail geometries and to optimize the sail parameters, e.g., camber and thickness. The lift and drag coefficients from CFD computations are later used as input to the performance prediction model ShipCLEAN, to perform studies with a real ship, a medium-sized tanker, using its operational data and hindcast weather. Results show the variation of performance of the sail due to changes in the geometry and the achievable energy savings of the ship in its real-life operation. Further, the performance of the crescent-type sail is benchmarked against the performance of Flettner rotors.
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| 9. |
- Zhu, Heng, 1995, et al.
(författare)
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Experimental study on structure responses of triple wing sails to turbulence flows at multiple apparent wind angles
- 2023
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Ingår i: Advances in the Analysis and Design of Marine Structures - Proceedings of the 9th International Conference on Marine Structures (MARSTRUCT 2023). - London : CRC Press. - 9781032506364 - 9781032506364 ; , s. 781-787
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Konferensbidrag (refereegranskat)abstract
- Wind-assisted propulsion for ships represented by wingsails is booming in today’s world. The cross-sectional shapes of wingsails are usually NACA profiles without camber, but a recent technology is to use crescent-shaped profiles with camber for remarkably higher aerodynamic lift. Unlike conventional NACA foils, the crescent-shaped foil has not deserved sufficient research regarding its structure responses to turbulence. In this paper, the structures of triple-lined-up crescent-shaped foils are investigated in wind-tunnel (WT) tests a scale on 1:100 compared to the full-size configurations. A wide range of apparent wind angles and wind speeds of interest are studied, to find out the critical angles and the best/worst performance points. Digital Image Correlation (DIC) is used to measure structural vibrations. Spectral analysis of the structural vibrations is performed to understand the coupled effects between the flow and the structures. The results can be used to guide the practical design of wing sails.
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| 10. |
- Zhu, Heng, 1995, et al.
(författare)
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Propulsive performance of a novel crescent-shaped wind sail analyzed with unsteady RANS
- 2022
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Ingår i: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. ; 7, s. 1-11
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Konferensbidrag (refereegranskat)abstract
- The use of wind-assisted ship propulsion is regarded as one of the effective ways to reduce greenhouse gas emissions. This study presents a numerical analysis of the aerodynamics of a single rigid wind sail using URANS (Unsteady Reynolds- Averaged Navier-Stokes equations). A new foil profile, the crescent-shaped foil, is proposed and then, compared with the classical profile NACA 0015. Both 2D and 3D simulations are conducted. The key physical quantities of interest are detailly discussed, such as the external loads on the sail, the induced flow field, as well as the propulsive performance. It is concluded that the wind sail with the crescent-shaped section has higher propulsion efficiency than that with NACA0015. However, flow separation is found for the former section. As the separation deteriorates the flow unsteadiness, this effect poses a challenge to the strength and stability of the wind sail structure. Moreover, the 3D simulations of both profiles, especially NACA 0015, show that the tip vortices induced from the sail side edge account for significant negative impacts on the propulsion performance.
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