Article
Chemistry, Physical
S. Meenakshi, Kapil Sonkar, Sachin Chugh, Rajesh Badhe, G. S. Kapur, S. S. V. Ramakumar
Summary: Membrane Electrode Assembly (MEA) in a Polymer Electrolyte Membrane Fuel Cell (PEMFC) is crucial for the performance of the fuel cell system. This study investigates the degradation of a stack operated MEA and characterizes it using electrochemical and physical methods. The results show that the MEA assembly decomposes at specific temperatures for the Nafion membrane, carbon-supported catalyst, and carbon-based GDL. The degradation is evidenced by the decrease of electrocatalyst surface area and the migration of catalyst particles.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Physical
Wan Yue, Diankai Qiu, Peiyun Yi, Linfa Peng, Xinmin Lai
Summary: In this study, a series of experiments were conducted to explore the degradation mechanism of the frame in the proton exchange membrane (PEM) fuel cell. It was found that acid solution contributes significantly to the failure of the frame, with peeling strength showing the most significant decline. The study reveals the degradation process of the frame for the first time, enhancing understanding of frame failure.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Energy & Fuels
Yue Wan, Diankai Qiu, Peiyun Yi, Linfa Peng, Xinmin Lai
Summary: The design of a gradient catalyst layer, with different wetting properties on each sub-layer, significantly enhances the performance of a proton exchange membrane fuel cell. The gradient layer improves the mass transfer capacity and power density of the fuel cell, resulting in higher efficiency.
Article
Energy & Fuels
Peng Ren, Pucheng Pei, Dongfang Chen, Yuehua Li, Ziyao Wu, Lu Zhang, Zizhao Li, Mingkai Wang, He Wang, Bozheng Wang, Xizhong Wang
Summary: This paper proposes a novel analytic method for MEA parameters using micro-current excitation, which allows for the simultaneous calculation of key parameters without the need for high sampling frequency and data filtering of voltage signals. The effects of operating conditions on MEA parameters, as well as the impact of relative humidity on hydrogen crossover, are further investigated in this study.
Article
Chemistry, Physical
Jared Beshai, Thomas DiSorbo, Jacob Hutfles, Jacob Segil, Richard F. ff Weir, John Pellegrino
Summary: This study presents the key characteristics of implementing cellulose acetate (CA) coatings on carbon cloth used as a fuel diffusion layer in aqueous fuel-fed cells, and demonstrates their functionality. The results show that these coatings enhance aqueous solution permeation and adhesion properties, leading to a two-fold increase in maximum power generation in alkaline DGFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Thermodynamics
Ali Jabbary, Sadra Rostami Arnesa, Hossein Samanipour, Nima Ahmadi
Summary: A numerical 3D procedure based on the Finite Volume Method is used to analyze PEMFC with a rhombus design, showing the impact of the design on output characteristics and the significant effect of water accumulation on cell performance. Model B improves current density and power consumption compared to the base model.
INTERNATIONAL JOURNAL OF GREEN ENERGY
(2021)
Article
Energy & Fuels
Dimitrij Jesic, Vivian Erklavec Zajec, David Bajec, Gregor Dolanc, Gorazd Bercic, Blaz Likozar
Summary: This study proposes a method for obtaining hydrogen from diesel energy for use in fuel cells, using catalytic auto-thermal reforming and water-gas shift technology. Through simulation and analysis, the design of the reactors and the influence factors were studied, and a successful construction and operation model was established.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Electrochemistry
Siddharth Komini Babu, Thomas O'Brien, Michael J. Workman, Mahlon Wilson, Rangachary Mukundan, Rod Borup
Summary: The corrosion of fuel cell components introduces contaminants that accelerate ionomer degradation, decreasing fuel cell durability. Altering gas diffusion layer wettability can affect cation contaminant transport, with the addition of a hydrophobic layer significantly suppressing contaminant transport and improving fuel cell performance.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Engineering, Industrial
A. Vasilyev, J. Andrews, S. J. Dunnett, L. M. Jackson
Summary: This paper develops a novel model for dynamic reliability analysis of a polymer electrolyte membrane fuel cell system to consider multi-state dynamics and ageing. By combining physical and stochastic sub-models, the study investigates the effects of operating conditions on system reliability. Monte Carlo simulations demonstrate the significant influence of purging and load cycles on the longevity of the fuel cell system.
RELIABILITY ENGINEERING & SYSTEM SAFETY
(2021)
Article
Electrochemistry
Andrei Kulikovsky
Summary: A recent single-pore model has been developed for analyzing the performance of cathode catalyst layer in low-Pt PEM fuel cells, and successfully used to fit experimental data to determine key parameters for improving cell performance.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Chemistry, Analytical
Andrei Kulikovsky
Summary: An analytical model for the concentration/pressure impedance on the cathode side of a PEM fuel cell has been developed, with analytical solution derived for the zeta impedance. Simple equations for the static point of zeta impedance have been obtained, allowing estimation of oxygen transport coefficients. The qualitative resemblance between the model and experimental zeta-spectrum has been demonstrated.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2021)
Article
Electrochemistry
Andrei Kulikovsky
Summary: A novel method is developed to calculate the cathode impedance of a PEM fuel cell based on charge and mass conservation equations. The cathode catalyst layer is divided into multiple sub-layers, and the steady-state variables within the sub-layers are assumed to be constant. By linearizing and Fourier-transforming the equations, analytical solutions for the overpotential and oxygen concentration perturbations are obtained for each sub-layer. Recurrent formulas are derived to express the perturbation amplitudes on one side of the sub-layer in terms of the values on the other side. By applying the recurrent relations multiple times from the CCL/GDL interface to the membrane surface, the system impedance can be obtained. The method shows high accuracy and tenfold acceleration in impedance spectrum calculations even with only 10 sub-layers and can be applied at arbitrary cell current.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Engineering, Chemical
Federico Perdomo, Matilde Abboud, Erika Teliz, Fernando Zinola, Veronica Diaz
Summary: The performance of a fuel cell depends on multiple factors, with the preparation of the membrane electrode assembly (MEA) being one of the most important. The study showed a significant dependence of charge transfer resistance on temperature, with pressure dependence being secondary. Changes in open circuit potential after varying temperature, pressure, and catalyst load were observed, affecting maximum power and efficiency.
INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING
(2021)
Article
Electrochemistry
Nammin Lee, Masoomeh Ghasemi, Bonghyun Kim, Seungbeen Choe, Kisung Lim, Seung Woo Lee, Seung Soon Jang, Hyunchul Ju
Summary: Air-cooled fuel cell systems are recognized as suitable technology for drone and aviation applications due to their lightweight and simple design. However, compared to liquid-cooled systems, they suffer from low specific power and unstable performance, mainly due to severe electrolyte dehydration and nonuniform current density and temperature profiles.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Yangbin Shao, Liangfei Xu, Jianqiu Li, Zunyan Hu, Yujie Ding, Weibo Zheng, Minggao Ouyang
Summary: The study proposed a novel experimental methodology to analyze the water management and other transient processes within PEMFC, showing that the transient capillary transport of liquid water within GDL dominates the lambda-V hysteresis under high humidification conditions, and successfully achieved three cycles of GDL imbibition/drainage in-situ for the first time.
JOURNAL OF POWER SOURCES
(2021)
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)