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Experimental and numerical study on improvement performance by wave parallel flow field in a proton exchange membrane fuel cell

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Chinese Journal of Chemical Engineering 2022年第5期35卷 90-102页

作者： Zijun Li Shubo Wang Sai Yao Xueke Wang Weiwei Li Tong Zhu Xiaofeng Xie School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Beijing Institute of Space Launch Technology Beijing 100076China

The performance and operation stability of proton exchange membrane fuel cells(PEMFCs)are closely related to the transportation of reactants and water management in the membrane electrode assembly(MEA)and flow field.In this paper,a new three-dimensional wave parallel flow field(WPFF)in cathode was designed and analyzed throughout simulation studies and an experimental method.The experimental results show that the performance of PEMFC with WPFF outperforms that of PEMFC with straight parallel flow field(SPFF).Specifically,the peak power density increased by 13.45%for the PEMFC with WPFF as opposed to PEMFC with SPFF.In addition,the flow field with area of 11.56 cm^(2) was formed by the assembly of transparent end plate used for cathode and the traditional graphite plate used for anode.To understand the mechanism of the novel flow field improving the performance of PEMFC,a model of PEMFC was proposed based on the geometry,operating conditions and MEA parameters.The thickness of gas diffusion layers(GDL),catalytic layers(CL)and proton exchange membrane were measured by scanning electron microscope.The simulation result shows that compared with SPFF,the WPFF based PEMFC promote the oxygen transfer from flow channel to the surface of CL through GDL,and it was beneficial to remove the liquid water in the flow channel and the MEA.

关键词： Fuel cells transport process Computational fluid dynamics Flow regimes Water management

Application of similarity theory in the study of proton exchange membrane fuel cells:a comprehensive review of recent developments and future research requirements

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Energy Storage and Saving 2022年第1期1卷 3-21页

作者： Fan Bai Le Lei Zhuo Zhang Li Chen Lei Chen Wen-Quan Tao Key Laboratory of Thermo-Fluid Science&Engineering of MOE Xi’an Jiaotong UniversityXi’an710049China

The diversity and complexity of the parameters involved in the modeling of proton exchange membrane fuel cells(PEMFCs)have restricted further research and applications of such cells,and the similarity theory is a promising solution to this problem.The similarity theory is an effective tool to obtain compact and generalized results with the same precision as that of the basic mathematical model.This paper presents a comprehensive review of the application of the similarity theory to most aspects of PEMFCs.The advantages of using the similarity theory,such as generality,reduction in the test effort,convenient comparisons and guidance to scale up the experiment,are discussed and analyzed.Although a number of similarity criteria have been proposed in recent years,the similarity theory is not as widely applied or well accepted in PEMFC research as in the heat transfer and fluid flow domain.The objective of this paper is to demonstrate the feasibility of performing a similarity analysis for such complex systems and encourage researchers to present a dimensionless expression of their results in the follow-up PEMFC research.A key challenge is to use the similarity analysis for a complete gas-water-electricity-heat-mechanics coupled with PEMFC system and obtain the correlation between the dimensionless output voltage/current and input similarity criteria.This review indicates that none of the existing models can achieve this objective,and further research pertaining to this aspect must be performed.Several recommendations to achieve this aim,including a hierarchical classification of the criteria,are provided.

关键词： Proton exchange membrane fuel cell Similarity theory transport process Membrane electrode assembly Contamination measurement Electrochemical kinetics

Control of diffuse P-pollutants by multiple buffer/detention structures by Yuqiao Reservoir, North China

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Journal of Environmental Sciences 2004年第4期16卷 616-620页

作者： WANGXia-hui YINCheng-qing SHANBao-qing ResearchCenterforEco-EnvironmentalSciences ChineseAcademy-ofSciencesBeijing100085China

A case study on the transport process of agricultural diffuse P-pollutants was conducted in an experimental watershed locating in the north bank of Yuqiao Reservoir during 2001 and 2002. It was found that diversified artificial and natural buffer/detention landscape structures distributing along the ephemeral stream channel in this watershed played an important role of pollutants removal on downstream water quality, especially they have control effect on the diffuse P-pollutants transport process. Surface flow velocity was reduced sharply after passing through these structures. During continuous runoff events, the removal rate of TSS, TP, TDP, DRP by the whole system were 66.7%, 60.7%, 48.4%, and 43.3%, respectively. During discontinuous runoff events, removal rate of pollutants by the whole system was higher due to there was no or little surface water and pollutants exported from the watershed, of which removal rate of pollutants all exceeded 99%. The statistical analysis results of runoff events(n=8) indicated that dry pond was the steadiest structure for controlling diffuse P-pollutants export.

关键词： diffuse P-pollutants buffer/detention structures removal transport process water quality

A dynamic coupling numerical model for pollutant transport under wave condition

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Acta Mechanica Sinica 2015年第1期31卷 53-61页

作者： Yong Li Mian Lin Zhen Wang Institute of Mechanics Chinese Academy of Sciences

In order to study the diffusion, migration, and distribution of pollutants among overlying waterbody and porous seabed under wave conditions, a dynamic coupling numerical model is proposed. In this model, the coupling between wave field of overlying waterbody and seepage of porous bed, the capture and release of pollutants in porous media, and the transport process between the two different regions are taken into account. We use the unified equa tions for pressure correction and pollutant concentration to solve the numerical model, which avoids repeated iteration on the interface boundary. The model is verified by several case studies. Afterwards, the processes involving release of pollutant from porous seabed and transportation to overly ing waterbody under different wave conditions are investi gated. The results show that the water depth, wave height, and wave period have great influences on the release, cap ture, and transport processes for phosphorus pollutant.

关键词： Wave Pollutant transport process Dynamiccoupling model Numerical analysis

Condensation behavior of gaseous phase during transported in the near-substrate boundary layer of plasma spray-physical vapor deposition

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Journal of Materials Science & Technology 2021年第8期67卷 127-134页

作者： Mei-Jun Liu Guan-Jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi'an fiaotong UniversityXi’anShaanxi710049PR China

Plasma spray-physical vapor deposition(PS-PVD)has exhibited the potential ability to prepare columnar structures for advanced thermal barrier coatings(TBCs).The coating structure is nominally affected by operating parameters,but it is controlled by the type of deposition unit actually and essentially.In order to realize the columnar structure deposited by gaseous phase units,the transition behavior of gaseous phase units to clusters must be fundamentally understood.This work investigated the transport process of gaseous phase units in the PS-PVD near-substrate boundary layer along with the condensation behavior.The Monte Carlo method was used to examine the transport process and condensation behavior of gaseous phase units under different scale boundary layers.Simulation results show that it is easier to form more numerous larger clusters at the edge of the plasma jet than at the center.Based on the understanding of the changes in deposition unit caused by the condensation of gaseous phase in the near-substrate boundary layer of PS-PVD,an outlook towards TBCs with different structures is presented.And it is in good agreement with the experimental data.

关键词： Condensation behavior transport process Cluster Boundary layer PS-PVD

Upriver transport of dissolved substances in an estuary and sub-estuary system of the lower James River, Chesapeake Bay

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Frontiers of Earth Science 2018年第3期12卷 583-599页

作者： Bo HONG Jian SHEN Hongzhou XU School of Civil and transportation Engineering South China University of Technology Guangzhou 510641 China Virginia Institute of Marine Science College of William & Mary Williamsburg VA2-3062 USA Institute of Deep-sea Science and Engineering Chinese Academy of Sciences sanya 572000 China

The water exchange between the James River and the Elizabeth River, an estuary and sub-estuary system in the lower Chesapeake Bay, was investigated using a 3D numerical model. The conservative passive tracers were used to represent the dissolved substances （DS） discharged from the Elizabeth River. The approach enabled us to diagnose the underlying physical processes that control the expansion of the DS, which is representative of potential transport of harmful algae blooms, pollutants from the Elizabeth River to the James River without explicitly simulating biological processes. Model simulations with realistic forcings in 2005, together with a series of processoriented numerical experiments, were conducted to explore the correlations of the transport process and external forcing. Model results show that the upriver transport depends highly on the freshwater discharge on a seasonal scale and maximum upriver transport occurs in summer with a mean transport time ranging from 15-30 days. The southerly/easterly wind, low river discharge, and neap tidal condition all act to strengthen the upriver transport. On the other hand, the northerly/westerly wind, river pulse, water level pulse, and spring tidal condition act to inhibit the upriver transport. Tidal flushing plays an important role in transporting the DS during spring tide, which shortens the travel time in the lower James River. The multivariable regression analysis of volume mean subtidal DS concentration in the mesohaline portion of the James River indicates that DS concentration in the upriver area can be explained and well predicted by the physical forcings （r = 0.858, p = 0.00001）.

关键词： transport process physical forcing numerical modeling estuary Chesapeake Bay