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  • Renewable Energy Storage and Sustainable Design of Hybrid Energy Powered Ships: A Case Study

    分类: 能源科学 >> 能源(综合) 提交时间: 2024-03-28

    摘要: With rapidly increasing consumption of energy, shipping industry has imposed a huge burden on the marine environment. It is a general trend to increase the use of renewable energy on ships to improve the ship sustainability. This article summarized the current development and application of solar energy, wind energy and fuel cell in ship power systems. Furthermore, in order to investigate the advantages of sustainable design for the ships, for the first time, a hybrid PV, wind and fuel cell energy system was established for an oil tanker, and the economic and environmental analyses of the hybrid system were performed. The analysis results demonstrate that the optimal hybrid energy system can reduce 151,467kg emission of CO2 and provide 2.92% electricity for the ship gird per year.

  • A new multi-sensor fusion approach for integrated ship motion perception in inland waterways

    分类: 交通运输工程 >> 水路运输 提交时间: 2024-03-31

    摘要: The ship motion perception approaches mainly use maritime radar, Automatic Identification System (AIS) and cameras. However, using either of these approaches alone may result in information inconsistency and insufficient data accuracy. Therefore, a multi-sensor fusion perception system is proposed in this study to monitor ship motion in inland waterways. Firstly, a hardware platform of multi-sensor fusion ship motion perception system composed of maritime radar, AIS, cameras and other accessories is constructed. Secondly, by utilizing the target detection and tracking algorithms, track association algorithms, the ship motion data collected from the three sensors are integrated. Finally, the performance of the ship motion perception system is verified by field experiments in day and night. The experimental results indicate that the integrated ship motion perception system with multiple sensors is able to improve the information consistency and data accuracy of ship motion apparently in inland waterway compared to other perception systems.

  • Machine learning calculation model for hydrodynamic lubrication characteristics of a miter gate bottom pivot

    分类: 机械工程 >> 机械设计 提交时间: 2024-03-31

    摘要: The bottom pivot is a vital support device in the miter gate but often subject to poor lubrication and wear failures. Calculating thehydrodynamic lubricationcharacteristics of the bottom pivot is a complex three-dimensional (3D) problem, and most of existing models adopt simplified assumptions to reduce the calculation difficulty. To solve this issue, this work develops a 3D model to calculate thehydrodynamic lubricationcharacteristics of the miter gate bottom pivot. Thefinite difference methodis used to solve theoil film thicknessand pressure distribution based on the spherical coordinatesReynolds equation. The component forces in three directions are calculated from the pressure distribution and compared with the theoretical values to generate the calculation difference. Then, thegenetic algorithm(GA) is used to minimize the difference to determine the optimal initial parameters for the 3D model. The analysis results show that the calculation accuracy can be significantly improved by using the optimal initial model parameters. When our initial pressure is 5.64MPa, the results meet the engineering accuracy requirements.

  • Damage identification of offshore jacket platforms in a digital twin framework considering optimal sensor placement

    分类: 水利工程 >> 水利工程其他学科 提交时间: 2024-04-01

    摘要: A new digital twin (DT) framework with optimal sensor placement (OSP) is proposed to accurately calculate the modal responses and identify the damage ratios of the offshore jacket platforms. The proposed damage identification framework consists of two models (namely one OSP model and one damage identification model). The OSP model adopts the multi-objective Lichtenberg algorithm (MOLA) to perform the sensor number/location optimization to make a good balance between the sensor cost and the modal calculation accuracy. In the damage identification model, the Markov Chain Monte Carlo (MCMC)-Bayesian method is developed to calculate the structural damage ratios based on the modal information obtained from the sensory measurements, where the uncertainties of the structural parameters are quantified. The proposed method is validated using an offshore jacket platform, and the analysis results demonstrate efficient identification of the structural damage location and severity.

  • Energy Storage Performance of Hydrogen Fuel Cells Operating in a Marine Salt Spray Environment using Experimental Evaluation

    分类: 能源科学 >> 储能技术 提交时间: 2024-03-31

    摘要: This work experimentally explores the influence of thesodiumchloride pollution on thePEMFC performancein the marine saltsprayenvironment by analyzing the concentration diffusion characteristics of the sodium chloride in thePEMFC membraneelectrodes. Firstly, a set of experiments were carried out to determine the distribution of the sodium chloride components in the membrane electrodes, where five different salt spray environments (i.e., 100mg/L, 200mg/L, 300mg/L, 400mg/L, and 500mg/L of the salt component, respectively) were used/employed to analyze the concentration diffusion characteristics of the sodium chloride. Then, the obtained samples were microscopically characterized and elementally analyzed by thefield emission scanning electron microscopy(FESEM) and the energy spectrometry. Subsequently, a least squares-based model was proposed to predict the diffusion rate of the contaminatingions inthe membrane electrodes. Lastly, the pollution of the sodium chloride was evaluated/assessed to reveal theperformance degradationof the PEMFCs. The experimental results demonstrated that (1) the sodium chloride fraction existed as crystals orions inthe membrane electrodes in the marine salt spray environment; (2) the sodium chloride poisoning was founded in theproton exchange membranein the form ofsodium ions; (3) and the sodium-to-chloride ratio was proportional to the contamination time and the salt spray in the proton exchange membrane.

  • A nonlinear African vulture optimization algorithm combining Henon chaotic mapping theory and reverse learning competition strategy

    分类: 工程与技术科学 >> 工程通用技术 提交时间: 2024-03-28

    摘要: As a new intelligentoptimization algorithm, the African vulturesoptimization algorithm(AVOA) has been widely used in various fields today. However, when solving complex multimodal problems, the AVOA still has some shortcomings, such as low searching accuracy, deficiency on the search capability and tendency to fall into local optimum. In order to alleviate the main shortcomings of the AVOA, a nonlinear African vulture optimization algorithm combining Henon chaotic mapping theory and reverse learning competition strategy (HWEAVOA) is proposed. Firstly, the Henon chaotic mapping theory and elite population strategy are proposed to improve the randomness and diversity of the vulture’s initial population; Furthermore, the nonlinear adaptive incremental inertial weight factor is introduced in the location update phase to rationally balance the exploration and exploitation abilities, and avoid individual falling into a local optimum; The reverse learning competition strategy is designed to expand the discovery fields for the optimal solution and strengthen the ability to jump out of thelocal optimal solution. HWEAVOA and other advanced comparison algorithms are used to solve classical and CEC2022 test functions. Compared with other algorithms, the convergence curves of the HWEAVOA drop faster and the line bodies are smoother. These experimental results show the proposed HWEAVOA is ranked first in all test functions, which is superior to the comparison algorithms in convergence speed, optimization ability, and solution stability. Meanwhile, HWEAVOA has reached the general level in thealgorithm complexity, and its overall performance is competitive in theswarm intelligence algorithms.

  • Conventional and advanced exergy-exergoeconomic exergoenvironmental analyses of an organic Rankine cycle integrated with solar and biomass energy sources

    分类: 能源科学 >> 能源(综合) 提交时间: 2024-03-29

    摘要: Considering the huge consumption of traditional energy and the rising demand for electricity, the development of renewable energy is very necessary. In this paper, an energy system integrating biomass energy, solar and two-stage organic Rankine cycle (ORC) is proposed, which uses the stable energy output of biomass energy to compensate for the volatility of solar modules. The proposed system comprises a biomass boiler, photovoltaic thermal panels (PV/T), evaporators, condensers, working medium pumps, turbines, a preheater and an air preheater. In addition, conventional and advanced exergy, exergoeconomic and exergoenvironmental (3E) analyses are carried out. Conventional 3E analyses reveal two components that require priority improvement. They are respectively evaporator 1 with the largest exergy destruction (708.2kW) and exergy destruction environmental impact rate (775.3 mPt/h) and evaporator 2 with the largest exergy destruction cost rate (19.15$/h).The results of advanced 3E analyses show that the largest avoidable endogenous exergy destruction is condenser 1 (136.6kW), the largest avoidable endogenous exergy destruction cost rate is condenser 2 (3.377$/h),and the largest avoidable endogenous exergy destruction environmental impact rate is condenser 1 (196.1mPt/h). These mean that these components have great potential for improvement in reducing exergy destruction, saving cost and protecting the environment. In addition, the avoidable endogenous exergy destruction/cost/environmental impact rate of evaporator 2 are negative, so evaporator 2 is not suitable as a priority component for improvement, which is contrary to the conclusions of conventional 3E analyses. It is found that conventional 3E analyses can only point out the biggest exergy destruction point, but cannot indicate whether the components with the greatest exergy destruction have the greatest potential for improvement. However, advanced 3E analyses can show the improvement potential of each component by improving its own performance and the external conditions. Therefore, it is necessary to conduct advanced 3E analyses.