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| 2. |
- Chuang, Zhenju, et al.
(författare)
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Numerical analysis of blade icing influence on the dynamic response of an integrated offshore wind turbine
- 2022
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018. ; 257
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Tidskriftsartikel (refereegranskat)abstract
- When a wind turbine is working in a cold and humid environment, icing may occur which lead to its performance reduction or even blades fracture. In this paper, a CFD-WTIA (Wind Turbine Integrated Analysis) coupled method is established to analyze the blade icing process and its influence on the overall dynamic performance of an integrated jacket-support offshore wind turbine. Firstly, motions of the blades are calculated by the WTIA method and used as input into CFD. Then, dispersed multi-phase model and melting-solidification model are used to simulate the icing growth phenomenon of three-dimensional blades. The k-ε turbulence model is used to calculate the aerodynamic performance before and after icing. Finally, the aerodynamic results after blade icing are returned to WTIA for integrated dynamic response acquisition. At the same time, the dynamic response of the wind turbine under the combined influence of ice and sea ice is analyzed. Results show that the blade ice-accretion increases linearly along the blade span-wise direction and is mainly concentrated on the leading edge of the blade. Lift and drag coefficients are seen deceased and increased respectively after icing. Power production, generator torque, rotor speed, as well as blade vibration are quantitatively studied. The methodology and findings of this paper can provide a good reference for the safety performance evaluation of an icing offshore wind turbine.
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| 3. |
- Huang, Luofeng, 1993, et al.
(författare)
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Ship resistance when operating in floating ice floes: derivation, validation, and application of an empirical equation
- 2021
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Ingår i: Marine Structures. - : Elsevier BV. - 0951-8339. ; 79:1, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- With the effects of global warming, the Arctic is presenting a new environment where numerous ice floes are floating on the open sea surface. Whilst this has improved Arctic shipping navigability in an unprecedented way, the interaction of such floes with ships is yet to be understood to aid the designing of ships and route planning for this region. To further explore this topic, the present work develops a procedure to derive an empirical equation that can predict the effects of such floes on ship resistance. Based on a validated computational approach, extensive data are extracted from simulations of three different ships with varying operational and environmental conditions. The ice-floe resistance is shown to strongly correlate with ship beam, ship buttock angle, ship waterline angle, ship speed, ice concentration, ice thickness and floe diameter, and the regression powers of each of the parameters on resistance are ascertained. This leads to a generic empirical equation that can swiftly predict ice-floe resistance for a given ship in a given condition. Subsequently, demonstrations are given on the incorporation of the derived equation into a set of real-time Arctic ship performance model and voyage planning tool, which can predict a ship’s fuel consumption in ice-infested seas and dynamically suggest a route with the least safety concern and fuel consumption. Moreover, the equation is validated by providing ice resistance prediction for experimental and full-scale conditions from multiple sources, showing high accuracy. In conclusion, the empirical equation is shown to give valid and rapid estimates for ice-floe resistance, providing valuable insights into ship designs for the region, as well as facilitating practical applications for polar navigation.
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| 4. |
- Bi, Lianjie, et al.
(författare)
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Influence of rare earth oxides on microstructure and mechanical properties of nickel-based superalloys fabricated by high energy beam processing: A review
- 2024
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Ingår i: Journal of Rare Earths. - 1002-0721. ; In Press
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Forskningsöversikt (refereegranskat)abstract
- In this paper, the effects of rare earth oxides on the microstructure and mechanical properties of nickel-based superalloys prepared by high-energy beam processing technology were critically studied. The focus is on the optimal amount of rare earth oxides that can produce ideal results. Special attention was paid to their main strengthening mechanisms, including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase. Y2O3, La2O3 and CeO2 rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying elements. These advantages can significantly improve the mechanical properties of the alloy. Thereafter, this paper outlines the future research directions of rare earth oxides, aiming to expand their application potential.
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| 5. |
- Huang, Luofeng, 1993, et al.
(författare)
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Ship resistance when operating in floating ice floes: a derivation of empirical equations
- 2020
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Ingår i: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. - 9780791884393 ; 7
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Konferensbidrag (refereegranskat)abstract
- With the effects of global warming, the Arctic is presenting a new environment where numerous ice floes are floating on the open sea surface. Whilst this has unprecedentedly improved Arctic shipping navigability and brought about significant opportunities, the interaction of such floes with ships has yet to be understood, thus hindering appropriate assessment of corresponding ship performance. This paper presents work on developing empirical equations to estimate the effects of such floes on ship resistance. Based on extensive data from validated computational simulations, the ice-floe resistance has been shown to correlate with ship beam, ship speed, ice concentration, ice thickness and floe diameter, and the regression powers of each the parameter on resistance are ascertained for a container ship. This leads to an empirical equation that can immediately predict ice-floe resistance in a given condition. The proposed approach has the potential to facilitate propulsion power estimates for Arctic shipping, as well as providing valuable insights into ship design for these environmental conditions.
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| 6. |
- Li, Zhiyuan, 1974, et al.
(författare)
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A comparison of two ship performance models against full-scale measurements on a cargo ship on the Northern Sea Route
- 2021
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Ingår i: Ships and Offshore Structures. - : Informa UK Limited. - 1754-212X .- 1744-5302. ; 16:sup 1, s. 237-244
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Tidskriftsartikel (refereegranskat)abstract
- The present paper introduces the development and verification of two ship performance models which have been implemented in a voyage planning tool designed for summer Arctic operations of commercial vessels. A novel ice resistance estimation algorithm for ice-floe conditions is implemented in the ship performance models. The fuel consumption predicted using both of the models are compared against full-scale measurements collected on a cargo ship of lower ice-class on the Northern Sea Route. This work found that both models meet the purpose of estimating ship fuel consumption for such a voyage planning tool and identified directions for future efforts. In addition, the typical transit scenarios in summer Arctic conditions presented in this study prove that a voyage planning tool with viable ship performance models facilitates Arctic shipping in a safe and sustainable way.
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| 7. |
- Li, Zhiyuan, 1974, et al.
(författare)
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A comparison of two ship performance models against full-scale measurements on a cargo ship on the Northern Sea Route
- 2020
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Ingår i: Proceedings of The 5th International Conference on Ships and Offshore Structures (ICSOS 2020). ; , s. 279-201
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Konferensbidrag (refereegranskat)abstract
- The present paper introduces the development and verification of two ship performance models which have been implemented in a voyage planning tool designed for Arctic operations of commercial vessels. An ice resistance estimation algorithm for ice-floe conditions is proposed and implemented in the ship performance models. The fuel consumption predicted using both of the models are compared against full-scale measurements collected on a cargo ship on the Northern Sea Route. Two further case studies representing different Arctic transit periods are also investigated. This work found that both models predict ship fuel consumption with good and satisfactory accuracy and identified directions for future efforts. Overall, the demonstrations prove that an Arctic voyage planning tool, combined with ship performance estimates taking into account the effect of ice and other environmental parameters, can facilitate safe and sustainable Arctic shipping.
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| 8. |
- Li, Zhiyuan, 1974, et al.
(författare)
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Cost–benefit analysis of a trans-arctic alternative route to the Suez canal: a method based on high-fidelity ship performance, weather, and ice forecast models
- 2023
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Ingår i: Journal of Marine Science and Engineering. - : MDPI AG. - 2077-1312. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- Climate change in recent years has produced viable shipping routes in the Arctic. However, critical uncertainties related to maritime operations in the Arctic make it difficult to predict ship speeds in ice and, thus, the voyage time and fuel costs. Cost–benefit analysis of alternative Arctic routes based on accurate environmental condition modeling is required. In this context, this paper presents a holistic approach that considers the major voyage-related costs of a trans-Arctic route as an alternative to the conventional routes via the Suez Canal Route (SCR) for existing merchant ships. This tool is based on high-fidelity models of ship performance, metocean forecasting, and a voyage optimization algorithm. Case studies are performed based on a general cargo vessel in operation to quantify realistic expenses inclusive of all the major operational, fuel, and voyage costs of the specific voyages. A comparison is made between the total costs of the trans-Arctic route and SCR for different seasons, which proves the economic feasibility of the trans-Arctic route. Overall, this work can provide valuable insights to help policymakers as well as shipbuilders, owners, and operators to assess the potential cost-effectiveness and sustainability of future Arctic shipping, thereby better developing future strategies.
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| 9. |
- Li, Zhiyuan, 1974, et al.
(författare)
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Safe and fuel-efficient voyage planning for the northeast passage by combining reliable ship performance, weather and ice forecast models
- 2020
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Ingår i: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE. - 9780791884393 ; 7
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Konferensbidrag (refereegranskat)abstract
- The Northeast Passage in the Arctic between Europe and Asia offers a significantly shorter voyage compared to the Southern route through the Suez Canal. In 2017, the EU research project “Safe maritime operations under extreme conditions: the Arctic case (SEDNA)” was established to perform a comprehensive analysis of Arctic transit shipping and to promote technical solutions for this purpose. This paper is based on the deliverables of the SEDNA project. A voyage planning tool (VPT) for Arctic applications was developed to plan the optimal route regarding ship’s fuel consumption and safety. One of the most advanced metocean and ice forecast model is utilized to provide comprehensive environmental conditions that are synchronized and will be updated frequently during the voyage. The ship energy system model takes into account the various environmental variables as well as ship’s operational conditions to compute the ship performance in both open and ice infested waters. For Arctic operations, specific ice resistance models are implemented in the VPT, and a user has the options of either relying on icebreaker assistance or going for unassisted navigation in part of the entire Arctic passage. Case study voyages of different ship types, route options, staring time, home/destination ports are simulated to demonstrate how various optimal routes are planned and how the transit time and fuel consumption vary. This information is considered being crucial for ship owners for planning their voyages in advance. The continuously updated voyage information from the VPT is particularly helpful for the ship crew if there are specific ship operations and risk mitigation actions that need to be taken care of during the voyage. In addition, this study underlines that a safe and fuel-efficient Arctic passage requires viable voyage planning tools that combine reliable ship performance with weather and ice forecasts.
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| 10. |
- Ringsberg, Henrik, 1974, et al.
(författare)
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CONTAINER SHIPPING VIA THE NORTH SEA ROUTE-OPPORTUNITIES AND CHALLENGES
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose Impact of global warming have increased the interests in containerised shipping via the North Sea Route (NSR). The purpose of this paper is to explore opportunities and challenges in feasibility in containerised shipping via the NSR as an alternative to the Suez Canal route (SCR). Methodology A structured literature review on navigational, economic, and geopolitical feasibility was conducted. Mixed methods approach was applied in a case study of containerised shipping between Rotterdam and Shanghai. Simulations were used to evaluate the navigational and economic feasibility of an ice-classed ship, semi-structured interviews were used to evaluate operational costs and geopolitical feasibility. Findings Containerised shipping via the NSR is not a navigational, economic, and geopolitical feasible option. Using the NSR create opportunities to decrease voyage time 11,5-14,7%, voyage cost by 15,7%, prevent congestion, increase goods volume in European ports. Using the NSR include challenges in increased operational costs, costs of insurance premiums, protection of the Arctic environment, and changes in geopolitical relationships. Research limitations A container ship used between Rotterdam and Shanghai, insurance and maintenance costs are included. Further empirical studies should include other routes, ships and crew costs to ensure generalisability. Practical implications A conceptual framework to evaluate containerised shipping via the NSR is presented. Social implications The Arctic Shipping Corporate Pledge to protect the Arctic environment is included. Original/value The paper is one of the few which evaluate containerised shipping based on navigational, economic, and geopolitical feasibility.
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