Query:
学者姓名:陶文铨
Refining:
Year
Type
Indexed by
Source
Complex
Co-Author
Language
Clean All
Abstract :
Commercial fuel cell stacks often have a large electrode area to obtain a high power output. Uniformity in-plane distribution of vital physical quantities plays a key role in improving cell performance and avoiding degradation. In this study, a three-dimensional two-fluid multiphase model is adopted to analyze the in-plane distribution characteristics of key parameters (reactant concentration, temperature, local current density, and membrane water content) for a large-scale PEMFC with an active area larger than 300 cm2. The particular feature of the PEMFC studied is that there are gap zones near the edge between the bipolar plate and gas diffusion layer and membrane. The results show that for the structure without gap zones, the cell performance improved by about 1%. The non-uniformity of cathode reactant distribution is generally higher than that of the anode; The non-uniformity of temperature in the x direction is higher than that in the y direction (flow-direction). With the increase of average current density, the temperature in the membrane increases, and the membrane dehydrates gradually. The flow direction of coolant has a significant impact on the cell performance. When coolant is in the same direction as hydrogen, the cell performance decreases by about 3.75% at 0.8 A/cm2. © 2022
Keyword :
Current density; Flow direction; Flow field; Large-scale; PEMFC
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Zhang, Z. , Wang, Q.-Y. , Bai, F. et al. Performance simulation and key parameters in-plane distribution analysis of a commercial-size PEMFC [J]. | Energy , 2023 , 263 . |
MLA | Zhang, Z. et al. "Performance simulation and key parameters in-plane distribution analysis of a commercial-size PEMFC" . | Energy 263 (2023) . |
APA | Zhang, Z. , Wang, Q.-Y. , Bai, F. , Chen, L. , Tao, W.-Q. . Performance simulation and key parameters in-plane distribution analysis of a commercial-size PEMFC . | Energy , 2023 , 263 . |
Export to | NoteExpress RIS BibTex |
Abstract :
Revealing the correlation between polarization curve and input parameters is a highly concerned topic in proton exchange membrane fuel cell (PEMFC) research. Till now, three-dimensional (3D) numerical models have been the most comprehensive methods to predict the polarization curve under variational conditions. However, due to the diversity and complexity of the parameters involved, an immense numerical or experimental burden is required to obtain the above-referred correlation based on 3D numerical model. Application of the similarity theory is considered as a promising breakthrough in PEMFC research to obtain generalized and compact laws. Activation criterion, a relative magnitude of the effect of temperature on electrochemical reaction rate versus the effect of activation overpotential, is the most important criterion on the PEMFC performance. Revealing its impact on the dimensionless polarization curve in the aspects of slope, intercept, and curvature is one of the major challenges for further investigation. Herein, a projection diagram is proposed to determine polarization curves under variation of activation criterion using similarity theory based on a series of results with other criteria variation. As a validation of the concept, two scenarios are exhibited by numerical approach. Results suggest that the maximum relative deviation of polarization curves predicted by the projection diagram is 0.14%, which reaches a high accuracy. The projection diagram reveals the reason why the activation criterion has a comprehensive and complex impact on the dimensionless polarization curve. © 2022 American Chemical Society. All rights reserved.
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Bai, F. , Tao, W.-Q. . Projection Diagram for Determining Polarization Curves under Variation of Activation Criterion Using Similarity Theory [J]. | ACS Omega , 2022 . |
MLA | Bai, F. et al. "Projection Diagram for Determining Polarization Curves under Variation of Activation Criterion Using Similarity Theory" . | ACS Omega (2022) . |
APA | Bai, F. , Tao, W.-Q. . Projection Diagram for Determining Polarization Curves under Variation of Activation Criterion Using Similarity Theory . | ACS Omega , 2022 . |
Export to | NoteExpress RIS BibTex |
Abstract :
A water droplet impacting onto a supercooled surface is typically considered to freeze and adhere to the substrate. This ice accretion poses safety and economic threats to transportation infrastructure, power generation/transmission systems, and telecommunication facilities. Here we report the observation of ultra-low ice-substrate adhesion (0-50 kPa) and remarkable self-deicing during droplet-impact freezing on copper surfaces having medium to high supercooling (30 degrees C-80 degrees C). Mechano-thermo-hydraulic coupling during droplet-impact freezing governs the ice-substrate adhesion by gap. ping the droplet-substrate contact, enabling self-peeling facilitated by thermal-mechanical stress relaxation. We observe a strong adhesion region in the center of the frozen droplet, which determines the adhesion strength, and develop a regime map to delineate the dependence of adhesion/peeling on droplet inertia, substrate supercooling, and surface wettability. Our work demonstrates key mechanisms governing ice-substrate adhesion during impact icing and presents an approach to passive self-deicing.
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Jin, Puhang , Yan, Xiao , Hoque, Muhammad Jahidul et al. Ultra-low ice-substrate adhesion and self-deicing during droplet impact freezing [J]. | CELL REPORTS PHYSICAL SCIENCE , 2022 , 3 (5) . |
MLA | Jin, Puhang et al. "Ultra-low ice-substrate adhesion and self-deicing during droplet impact freezing" . | CELL REPORTS PHYSICAL SCIENCE 3 . 5 (2022) . |
APA | Jin, Puhang , Yan, Xiao , Hoque, Muhammad Jahidul , Rabbi, Kazi Fazle , Sett, Soumyadip , Ma, Jingcheng et al. Ultra-low ice-substrate adhesion and self-deicing during droplet impact freezing . | CELL REPORTS PHYSICAL SCIENCE , 2022 , 3 (5) . |
Export to | NoteExpress RIS BibTex |
Abstract :
The critical heat flux (CHF) of flow boiling in a mini-channel is vital for equipment safety, but the boiling crisis triggering mechanism has been proved unsatisfactory. In this study, the VOSET method is adopted to investigate CHF of subcooled flow boiling in a vertical rectangular mini-channel by considering the conjugated heat transfer and using a reasonable nucleation site density model. Hundred of bubbles are accurately captured, and the evolutions of flow pattern, dry patch, and wall superheating are reproduced. Based on those, the relationship between boiling crisis and dry patch is demonstrated. When the heat flux is lower, some middle-sized isolated bubbles adhere to the wall surface with a dry patch below. This dry patch can be rewetted quickly. Hence, the wall superheating increases slightly along the flow direction and is within control. With the increasing heat flux, the dry patch expands because some big bubbles merge into the elongated bubble, leading to the local heat transfer deterioration, but the local wall superheating rise is still limited due to heat conduction inside the solid wall and the rewetting effect. However, the continuous coalescence of elongated bubbles midstream and downstream causes the appearance of an almost permanent dry patch with a high local wall superheating of 183.04 K near the outlet of the mini-channel when the heat flux rises to 500 kW/m2, which has exceeded the CHF of 375 kW/m2 obtained in this study. This triggering mechanism of the flow boiling crisis is new and different from the traditional ones. Besides, the departure from nucleate boiling (DNB) is found at 325 kW/m2, beyond which the wall superheating increases rapidly with heat flux.
Keyword :
Critical heat flux Flow boiling Mini-channel VOSET method
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Chen, Yu-Jie , Ling, Kong , Jin, Shu-Qi et al. Numerical investigation of critical heat flux during subcooled flow boiling in a vertical rectangular Mini-channel [J]. | APPLIED THERMAL ENGINEERING , 2022 , 221 . |
MLA | Chen, Yu-Jie et al. "Numerical investigation of critical heat flux during subcooled flow boiling in a vertical rectangular Mini-channel" . | APPLIED THERMAL ENGINEERING 221 (2022) . |
APA | Chen, Yu-Jie , Ling, Kong , Jin, Shu-Qi , Lu, Wei , Yu, Bo , Sun, Dongliang et al. Numerical investigation of critical heat flux during subcooled flow boiling in a vertical rectangular Mini-channel . | APPLIED THERMAL ENGINEERING , 2022 , 221 . |
Export to | NoteExpress RIS BibTex |
Abstract :
A three-dimensional conjugated numerical simulation is conducted to investigate subcooled flow boiling in a horizontal rectangular mini-channel based on the interface capturing method (VOSET). A reasonable nucleation density site model based on experimental results is adopted. Hundreds of bubbles with different sizes are successfully captured . Simulation results reproduce typical processes of subcooled boiling flow: growth, coalescence, detachment, and condensation of bubbles. And different flow boiling patterns, including pseudo bubbly flow, bubbly flow, slug flow, and pattern transition, are visualized under different heat fluxes. Furthermore, the effects of heat flux and vapor fraction on heat transfer coefficient are discussed in detail. Heat transfer deterioration is observed for high heat flux because of the formation of dry patches, and the complexity of heat transfer performance varying with vapor fraction is found. Based on those, the heat transfer mechanisms of subcooled flow boiling at different heat flux in the present mini-channel are discussed. (c) 2021 Elsevier Ltd. All rights reserved.
Keyword :
Flow pattern Heat flux Numerical simulation Subcooled boiling flow VOSET
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Chen, Yu-Jie , Ling, Kong , Ding, Hao et al. 3-D numerical study of subcooled flow boiling in a horizontal rectangular mini-channel by VOSET [J]. | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 183 . |
MLA | Chen, Yu-Jie et al. "3-D numerical study of subcooled flow boiling in a horizontal rectangular mini-channel by VOSET" . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 183 (2022) . |
APA | Chen, Yu-Jie , Ling, Kong , Ding, Hao , Wang, Yun , Jin, Shu-Qi , Tao, Wen-Quan . 3-D numerical study of subcooled flow boiling in a horizontal rectangular mini-channel by VOSET . | INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER , 2022 , 183 . |
Export to | NoteExpress RIS BibTex |
Abstract :
Under a low flow rate, gravity may become prominent for bubble behavior and heat transfer of flowing boiling because of the weakness of drag force from liquid, and its effect changes with the inclination angle of the mini-channel but without consensus. In this paper, based on a reasonable nucleus site density model and considering conjugate heat transfer, the coupled volume-of-fluid and level set method is adopted to study the subcooled flow boiling in an inclined three-dimensional rectangular mini-channel (0 degrees-180 degrees) with a characteristic size of 1.0 mm at a low flow rate of 88.8 kg m(-2) s(-1). The inclination angle is found to have a slight effect on the flow boiling, which is different from the conclusion drawn based on the traditional-macro channel. A bubbly flow appears when a heat flux of 300 kW/m(2) is added. An unconventional impact force is proposed, which presses large bubbles to slip along the heating wall, with slight differences in the flow pattern under different inclination angles. When the inclination angle is close to 0 degrees, the upstream small/medium bubbles leave the heating wall under gravitational effects, which is conducive to heat transfer. As the inclination angle approaches 90 degrees, gravity pushes the large bubbles downstream to leave the channel, favoring the rewetting of the dry patches below. These two positive effects fail as the inclination angle approaches 180 degrees, leading to slightly worse overall heat exchange efficiency. However, the maximum differences in the average and local wall superheating of the mini-channel are only 8.4% and 22.5%, respectively, across the range of inclination angles because the flow pattern remains similar under the effect of the impact force. In addition, the effect of inclination angle on flow boiling becomes weaker with the increase in heat flux because of happening of slug flow.
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Chen, Yu-Jie , Song, Ge-Ge , Ling, Kong et al. Numerical investigation of subcooled flow boiling in an inclined rectangular mini-channel at a low flow rate [J]. | PHYSICS OF FLUIDS , 2022 , 34 (11) . |
MLA | Chen, Yu-Jie et al. "Numerical investigation of subcooled flow boiling in an inclined rectangular mini-channel at a low flow rate" . | PHYSICS OF FLUIDS 34 . 11 (2022) . |
APA | Chen, Yu-Jie , Song, Ge-Ge , Ling, Kong , Yu, Bo , Sun, Dongliang , Lu, Wei et al. Numerical investigation of subcooled flow boiling in an inclined rectangular mini-channel at a low flow rate . | PHYSICS OF FLUIDS , 2022 , 34 (11) . |
Export to | NoteExpress RIS BibTex |
Abstract :
The cold start-up of the PEMFC (proton exchange membrane fuel cell) stack from sub-zero temperature is considered one of the significant obstacles to its expansive commercial applications. In the cold start-up process, with the progress of hydrogen/oxygen chemical reaction, the produced water will freeze into ice, occupying the pores of the porous electrode, thus leading to a rapid deterioration of output performance and even making the cold start-up fail. In this work, a one-dimensional numerical model is adopted to study a cold start-up process of the PMEFC stack starting from -30 degrees C. The stepwise-changed current loading mode is employed in the process. An assisted preheating method is used to explore an optimal operating condition for a successful cold start-up. The numerical results are validated by comparing the numerical result with the experimental data in reference, and they agree with the experimental data very well. The results show that the optimal heating power in the studied range is 100 W. As the initial current slope increased, the current peak value increased, but the cold start-up process failed. Also, the start-up time and ice volume fraction are highly dependent on the initial current slope. The optimal initial current slope is 0.7 A/s. Besides, a higher initial current slope will cause a significant inner ohmic resistance. The resistance of CLa (catalyst layer of the anode) is the key and primary part of the total ohmic resistance. The details of the research and the analyzed results will help design the cold start-up strategy for the PEMFC stack start-up from -30 degrees C.
Keyword :
cold start-up PEMFC stack preheating stepwise-changed current loading mode
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Lei Le , He Pu , He Peng et al. Numerical Research on the Cold Start-up Strategy of a PEMFC Stack from-30 degrees C [J]. | JOURNAL OF THERMAL SCIENCE , 2022 . |
MLA | Lei Le et al. "Numerical Research on the Cold Start-up Strategy of a PEMFC Stack from-30 degrees C" . | JOURNAL OF THERMAL SCIENCE (2022) . |
APA | Lei Le , He Pu , He Peng , Tao Wen-quan . Numerical Research on the Cold Start-up Strategy of a PEMFC Stack from-30 degrees C . | JOURNAL OF THERMAL SCIENCE , 2022 . |
Export to | NoteExpress RIS BibTex |
Abstract :
液态金属拥有很好的导热性,作为冷却介质具有广泛的应用前景,但其分子普朗特数远小于常规流体,导致换热特性与常规流体存在差异.本文对Ra=104~107范围内热面向上水平平板上液态铅铋合金的自然对流换热进行了数值模拟研究,对比了不同瑞利数下温度场的差异,并给出了 Ra=104~107范围内平均努塞尔数的计算公式.
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | 丁昊 , 陶文铨 . 水平热板上液态金属自然对流的数值模拟 [J]. | 工程热物理学报 , 2021 , 42 (8) : 2035-2039 . |
MLA | 丁昊 et al. "水平热板上液态金属自然对流的数值模拟" . | 工程热物理学报 42 . 8 (2021) : 2035-2039 . |
APA | 丁昊 , 陶文铨 . 水平热板上液态金属自然对流的数值模拟 . | 工程热物理学报 , 2021 , 42 (8) , 2035-2039 . |
Export to | NoteExpress RIS BibTex |
Abstract :
The thermal conductance in Nafion molecular chain is investigated by VASP, Phonopy, and ShengBTE based on the first-principle calculation. By using the mechanical structural analysis and chemical bond analysis of crystal orbital overlap population, the strength of carbon-carbon bond, carbon-oxygen bond, and carbon-sulfur bond is discussed. Combined with the pDOS (phonon density of state) analysis, we have determined that the backbone linked by carbon-carbon bonds is always the main route of phonon transport in the Nafion molecular chain, and the branches with sulfonate ions also play a non-negligible phonon transfer role in the local molecular chains. The results of thermal conductivity calculation prove the above analysis that the thermal conductivity of the Nafion molecular chain is much higher than that of the bulk/ membrane, but still at a lower level [12C/13C graphene superlattice). © 2020 by Begell House, Inc. www.begellhouse.com
Keyword :
Carbon Chemical analysis Covalent bonds Phonons Thermal conductivity
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Nie, Yi-Nan , Chen, Lei , Tao, Wen-Quan . Thermal conductivity of nafion molecular chain based on first-principle calculation [J]. | Heat Transfer Research , 2021 , 51 (12) : 1123-1133 . |
MLA | Nie, Yi-Nan et al. "Thermal conductivity of nafion molecular chain based on first-principle calculation" . | Heat Transfer Research 51 . 12 (2021) : 1123-1133 . |
APA | Nie, Yi-Nan , Chen, Lei , Tao, Wen-Quan . Thermal conductivity of nafion molecular chain based on first-principle calculation . | Heat Transfer Research , 2021 , 51 (12) , 1123-1133 . |
Export to | NoteExpress RIS BibTex |
Abstract :
In this paper, the molecular dynamics method is conducted to study the effects of hydrophilic-hydrophobic composite groove substrate on bubble nucleation. The differences in nucleation behavior and nucleation rate are compared between hydrophilic-hydrophobic composite groove substrate and the groove substrate with uniform hydrophilicity and hydrophobicity, respectively. The results show that a visible bubble nucleus appears on the substrates with different wettability conditions after a period of heating on liquid argon, but the nucleation behaviors are different. The heat transfer efficiency of solid-liquid increases with the enhancement of hydrophilicity, while the potential barrier of nucleation for liquid atoms in the vicinity of the substrate decreases with the enhancement of hydrophobicity. The hydrophilic-hydrophobic composite groove has characteristics of high heat transfer efficiency on the hydrophilic side and low nucleation potential barrier on the hydrophobic side, leading to the promotion of bubble nucleation. © 2021, Science Press. All right reserved.
Keyword :
Crystallization Efficiency Heat transfer Hydrophilicity Hydrophobicity Liquefied gases Molecular dynamics Nucleation Substrates
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Chen, Yu-Jie , Yu, Bo , Tao, Wen-Quan . Molecular Dynamics Study of Bubble Nucleation on the Substrate With a Hydrophilic-hydrophobic Composite Groove [J]. | Journal of Engineering Thermophysics , 2021 , 42 (10) : 2615-2624 . |
MLA | Chen, Yu-Jie et al. "Molecular Dynamics Study of Bubble Nucleation on the Substrate With a Hydrophilic-hydrophobic Composite Groove" . | Journal of Engineering Thermophysics 42 . 10 (2021) : 2615-2624 . |
APA | Chen, Yu-Jie , Yu, Bo , Tao, Wen-Quan . Molecular Dynamics Study of Bubble Nucleation on the Substrate With a Hydrophilic-hydrophobic Composite Groove . | Journal of Engineering Thermophysics , 2021 , 42 (10) , 2615-2624 . |
Export to | NoteExpress RIS BibTex |
Export
Results: |
Selected to |
Format: |