随着化石能源的日渐枯竭,海洋热能转换系统(Ocean thermal energy conversion, OTEC)是可以利用海水间的温差将清洁、可再生的海洋能转换为电能的能源系统,关于该系统的研究已引起了越来越多的关注与研究.在工作过程中,浮式海浪温差发...随着化石能源的日渐枯竭,海洋热能转换系统(Ocean thermal energy conversion, OTEC)是可以利用海水间的温差将清洁、可再生的海洋能转换为电能的能源系统,关于该系统的研究已引起了越来越多的关注与研究.在工作过程中,浮式海浪温差发电系统中用于传输深层低温海水的管道会受到外界环境的影响产生振动,而这些振动会直接影响系统的性能.本文将研究该柔性系统的振动控制问题,首先,建立用一个偏微分方程和一组常微分方程组成的模型来描述OTEC系统的动力学特性,并直接基于系统的动力学模型设计主动的边界控制器以及边界扰动观测器,从而消除外界扰动的影响,以及减少OTEC系统中柔性管道的横向形变,抑制系统的振动.此外,本文还考虑了OTEC系统中存在的输出约束问题,并且在所设计边界控制律的作用下,从理论上证明OTEC系统的稳定性,保证OTEC系统中的柔性管道的形变量最终收敛于平衡点附近以及浮式平台固定在初始位置附近.最后,通过选择合适的控制参数来对OTEC系统进行数字仿真,利用所得到的仿真结果验证了所设计控制律的有效性.展开更多
Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performanc...Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.展开更多
文摘随着化石能源的日渐枯竭,海洋热能转换系统(Ocean thermal energy conversion, OTEC)是可以利用海水间的温差将清洁、可再生的海洋能转换为电能的能源系统,关于该系统的研究已引起了越来越多的关注与研究.在工作过程中,浮式海浪温差发电系统中用于传输深层低温海水的管道会受到外界环境的影响产生振动,而这些振动会直接影响系统的性能.本文将研究该柔性系统的振动控制问题,首先,建立用一个偏微分方程和一组常微分方程组成的模型来描述OTEC系统的动力学特性,并直接基于系统的动力学模型设计主动的边界控制器以及边界扰动观测器,从而消除外界扰动的影响,以及减少OTEC系统中柔性管道的横向形变,抑制系统的振动.此外,本文还考虑了OTEC系统中存在的输出约束问题,并且在所设计边界控制律的作用下,从理论上证明OTEC系统的稳定性,保证OTEC系统中的柔性管道的形变量最终收敛于平衡点附近以及浮式平台固定在初始位置附近.最后,通过选择合适的控制参数来对OTEC系统进行数字仿真,利用所得到的仿真结果验证了所设计控制律的有效性.
基金supported by the Key Project of Natural Science Fund of Shandong Province (ZR2011BZ008)the Marine Renewable Energy Special Fund Project from the State Oceanic Administration PRC (GHME2011GD04)+2 种基金the Scientific and Technology Development Plan Project of Shandong Province,China (2008GG10007003)the Key Laboratory of Submarine Geoscience and Exploring Technology of the Ministry of Education,Ocean University of China (Grant No. 2008-01)the Key Laboratory of Marine Environment & Ecology,Ministry of Education (Grant No. 2008010)
文摘Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.
基金Supported by the National Natural Science Foundation of China(61873153)the Youth Science and Technology Research of Shanxi Province(201801D221013)the Science and Technology Innovation Fund Project of Shanxi Agricultural University(2017ZZ06).
