Numerical simulation of diffusivity of hydrogen in thin tubular metallic membranes affected by self-stresses

Zhang, Wu-Shou; Hou, Meiying; Wang, Heyi; Fu, Yongchun

doi:10.1016/j.ijhydene.2003.10.007

Cited by 8 publications

(6 citation statements)

References 38 publications

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“…The maximum rate proportional to the difference between P up and phase transition pressure leads to the rate-limiting step of Langmuir adsorption or Knudsen flow in voids according to [27]. However, the analysis does not take into account the effects of temperature change, stress gradient [28,29,30], and dislocations [31,32]. In particular, the phase transition to LaNi 5 H 6 is an exothermal reaction, which changes the reaction rates.…”

Section: Resultsmentioning

confidence: 99%

“…Palladium is “prohibitively [34]” expensive, and LaNi 5 is more economical. Moreover, though the sample is subjected to less load in this work, hydrogen storage ability is changed by stress [28,29,30]. The swelling behavior change under stress is important information because an actuator receives the reactive force, which is a topic for future research.…”

Section: Resultsmentioning

confidence: 99%

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Suitability Evaluation of LaNi5 as Hydrogen-Storage-Alloy Actuator by In-Situ Displacement Measurement during Hydrogen Pressure Change

et al. 2019

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The swelling ability of LaNi5 for application to hydrogen-storage-alloy (HSA) actuator is discussed through the measurement of the swelling ratio in hydrogen. The HSA actuator is driven by hydrogen pressure change causing the swelling of HSA. LaNi5 is one of the candidate materials for HSA actuators as well as palladium. Some prototypes of HSA actuators using LaNi5 have been fabricated; however, the kinetic swelling ability of LaNi5 itself has been not investigated. In this paper, the authors investigated the static and kinetic swelling ability of LaNi5 powder under hydrogen atmosphere. The results showed that the swelling ratio increased by 0.12 at the phase transition pressure. Response time decreased with an increase in the charged pressure during absorption, while it remained constant during discharge. Reaction kinetics revealed that these swelling behaviors were explained by hydrogen absorption and lattice expansion. The swelling ability of LaNi5 was also compared with that of palladium. The results show that LaNi5 swells 1.8 times more than palladium under 0.5 MPa. LaNi5 is suitable for an actuator driven repeatedly under more than the phase transition pressure. Palladium can be used for one-way-operation actuator even under 0.1 MPa since its response time during the evacuation was much longer than during the pressurization.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Suitability Evaluation of LaNi5 as Hydrogen-Storage-Alloy Actuator by In-Situ Displacement Measurement during Hydrogen Pressure Change

et al. 2019

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“…This method is a common method used in the literature to smoothen raw experimental data. 24) The average concentration profiles from four scans per sample and two samples per diffusion condition resulted in two average profiles per diffusion time. This averaging process reduced the variations in the concentration profiles used to extract interdiffusion coefficients.…”

Section: Methodsmentioning

confidence: 99%

Analysis of Concentration Dependence of Interdiffusion Coefficient under the Condition of a Time-Varying Surface Concentration

Olaye

Ojo

2022

Mater. Trans.

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The newly reported forward simulation method is used to extract concentration-dependent interdiffusion coefficient (D=F(C)) from experimental concentration profiles obtained under constant and time-varying surface concentration conditions, which is impossible by the standard analytical methods. Also, theoretical D=F(C) under constant and time-varying surface concentration conditions are computed in systems with diffusion-induced stress generation and relaxation. The experimental and theoretical results show that the long-held general assumption that D=F(C) is the same for constant surface concentration and time-varying surface concentration is not valid, and such assumption can cause model prediction errors in cases where a surface concentration changes with time. These include the use of D=F(C) computed by the standard analytical techniques, such as the Boltzmann-Matano, Sauer-Freise, Hall, and Wagner methods, for predicting diffusion during homogenization processes.

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“…In the simulation, hydrogen diffusion was driven not only by concentration gradient but also by stress gradient. Most of the papers relevant to the stress-induced diffusion [21][22][23][24][25][26][27][28] focus on hydrogen embrittlement in steel and hydrogen permeable membranes, in which hydrogen content is small enough to neglect the effect of volume and activity change with hydrogen content. In the actuator's applications, these effects should be taken into account since the hydrogen content can be high.…”

Section: Numerical Simulation Of Hsa Actuator's Responsementioning

confidence: 99%

“…The diffusion is promoted not only by a hydrogen content gradient (Fick's law) but also by a stress gradient [23,24]. Many researchers [25][26][27][28] simulated diffusion of hydrogen atoms in a hydrogen storage alloy under stress, which revealed that the so-called stress-induced diffusion (SID) plays an important role in the diffusion behavior. In the actuator, the stress effect cannot be negligible because it receives a reaction force during operation.…”

Section: Introductionmentioning

confidence: 99%

Deformation mechanism of capsule-type hydrogen-storage-alloy actuator

Goto

Hirata

Higuchi

et al. 2019

International Journal of Hydrogen Energy

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Numerical simulation of diffusivity of hydrogen in thin tubular metallic membranes affected by self-stresses

Cited by 8 publications

References 38 publications

Suitability Evaluation of LaNi5 as Hydrogen-Storage-Alloy Actuator by In-Situ Displacement Measurement during Hydrogen Pressure Change

Suitability Evaluation of LaNi5 as Hydrogen-Storage-Alloy Actuator by In-Situ Displacement Measurement during Hydrogen Pressure Change

Analysis of Concentration Dependence of Interdiffusion Coefficient under the Condition of a Time-Varying Surface Concentration

Deformation mechanism of capsule-type hydrogen-storage-alloy actuator

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