The tool design and experiments on pulse electrochemical machining of micro channel arrays on metallic bipolar plate using multifunctional cathode

Liu, Guixian; Zhang, Yongjun; Yu, Dingwen; Wei, Hongyu; Zhou, Chao; Liu, Jiangwen; Luo, Hui

doi:10.1007/s00170-016-9064-8

Cited by 16 publications

(9 citation statements)

References 24 publications

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“…Furthermore, Equation (2) was solved considering the convective flux Equation (10). Meanwhile, Equation (10) was solved using the velocity in the pore [17] and mass flux vectors [18,19], and these latter equations were determined by electrode-reaction kinetics [20].…”

Section: Methodsmentioning

confidence: 99%

“…The equations are written in indicial-tensor notation with: ρ, density kg/m 3 ; t, time s; µ dynamic viscosity of oxygen = 2 × 10 −5 Pa-s (5); u, velocity vector m/s; p, pressure Pa; ω i weight fraction of the i th species; with an inlet mass fraction O 2 = 0.1447, a mass fraction of H 2 O = 0.3789, and a mass fraction of N 2 = 0.4764; D e f f ,ij , the effective binary diffusion coefficient (see Equation (4) in [22][23][24]); M, the total molar mass of the mixture g/mol (see Equation (5) in [19][20][21][25][26][27]); M j , the molecular weight of species j, g/mol; MO 2 , the molecular weight of O 2 = 32 g/mol; M H2O , the molecular weight of H 2 O = 18 g/mol; M N2 , the molecular weight of N 2 = 28 g/mol; D ij , the binary diffusion coefficient for species i and j; k, the Maxwell diffusion constant = 3.16 × 10 −8 Pa·m 2 /s; T, temperature = 353 • K; ν i , the molar diffusion volume of the j th species, cm 3 /mol; ν O2 , the molar diffusion volume of O 2 = 16.6 × 10 −6 cm 3 /mol; νH 2 O, molar diffusion volume of H 2 O = 12.7 × 10 −6 cm 3 /mol; νN 2 , the molar diffusion volume of N 2 = 17.9 × 10 −6 cm 3 /mol; for M j , MO 2 , MH 2 O, and MN 2 , see Table 1; ε, porosity = 0.5; i c , cathode current; S a specific surface area = 1 × 10 7 m 2 /m 3 ; δ, active layer thickness = 10 um; i 0 , exchange current density = 1.06 × 10 −6 mA/cm 2 ; F, Faraday's constant = 96485 C/mol, R, gas constant = 8.314 J/(mol·K); η overpotential between 0.2 and 0.82 V; t H 2 O electro-osmotic drag = 3; gdl, gas diffusion layer thickness = 0.2 mm.…”

Section: Name Equations Numbermentioning

confidence: 99%

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Flow Analysis Based on Cathodic Current Using Different Designs of Channel Distribution In PEM Fuel Cells

et al. 2019

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In this work, a physical and numerical simulation of cathodic current for different designs of the channel distribution in PEM fuel cells was carried out. The first design consisted serpentine-type channels with abrupt changes in flow direction. On the other hand, Designs 2 and 3 were made of serpentine channels with a more gradual change in flow direction. The fourth design was a crisscross-type channel, which was based on continually redirecting the flow, while Design 5 was made with straight parallel channels. Designs 1–3 had one intake, while Designs 4 and 5 had three. The latter two produced more uniform electrical current distributions than Designs 1–3. It can be concluded that the intakes situated effectively within each design were as important as the shape of the channel configuration. Finally, the parallel channel flow field (Design 5) was the best alternative for current collectors due to its better performance.

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Section: Methodsmentioning

confidence: 99%

Section: Name Equations Numbermentioning

confidence: 99%

Flow Analysis Based on Cathodic Current Using Different Designs of Channel Distribution In PEM Fuel Cells

et al. 2019

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Section: Introductionmentioning

confidence: 99%

“…Pan et al presented an electrochemical micro-machining method with cathode vibration feed based on the mechanics of vibration and the electrochemical principle [14]. Yang et al improved electrolyte diffusion and convection by applying ultrasonic vibrations [15], and Liu et al improved the flow field of machining regions in the process with tool vibration [16]. Previous research into PVECM focused on how pulse and vibration parameters such as vibration frequency, vibration amplitude, and pulse duration affect machining accuracy and surface quality [10,[17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Research on Stagger Coupling Mode of Pulse Duration and Tool Vibration in Electrochemical Machining

et al. 2018

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Tuning the coupling of pulse duration and tool vibration in electrochemical machining (PVECM) is an effective method to improve machining accuracy and surface quality. In general, the pulse is set at the same frequency as the tool vibration, and a symmetrical distribution is attained at the minimum inter-electrode gap. To analyse the characteristics of the electrolyte fluid flow and of the electrolysis products in the oscillating inter-electrode gap, a dynamic simulation of the PVECM process was carried out. The simulation results indicated that the electrolyte pressure and gas void fraction when the pulse arrived as the inter-electrode gap was narrowing clearly differed from those when the inter-electrode gap was expanding. Therefore, in addition to the traditional symmetry coupling mode, two other coupling modes called the pre-position and the post-position coupling modes are proposed which use a pulse either just before or just after the minimum inter-electrode gap. Comparative experiments involving the feed rate and machining localization were carried out to evaluate the influence of the three coupling modes. In addition, current waveforms were recorded to analyse the differences between the three coupling modes. The results revealed that the highest feed rate and the best machining localization were achieved by using the pre-position coupling mode.

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“…This could reduce the surface quality and process stability, even worst, a short circuit will happen. To improve the flow field in the third way of ECM process, Zhang et al designed a multi-functional cathode that filled with elastic blocks [13], and Liu et al introduced low frequency tool vibrations in ECM [14].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Machining Multiple Slots of Bipolar Plates with Tool Vibration

Jiang¹,

Astronautics²

2018

International Journal of Electrochemical Science

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A bipolar plate is an important component of proton exchange membrane fuel cells (PEMFC). The fabrication of multiple slots is a key part in preparation of metallic bipolar plates. They can be produced by electrochemical machining (ECM). During the ECM process, high flow resistance occurs with the increase of slots length and depth, which will make metal hydroxide and other by-products accumulate in the outlet of electrolyte and limit the maximum feed rate of cathode. Therefore, a flow channels contraction cathode structure with variable cross-section has been proposed. It can make the flow velocity of electrolyte increase gradually in the inter-electrode gap and take away electrolysis products better. In order to remove electrolysis products further, tool vibration is applied. The flow channels contraction cathode has been determined with numerical simulations, and the comparison experimental results show that the way is effective in improving the feed rate and ensuring the uniformity of slots depth.

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The tool design and experiments on pulse electrochemical machining of micro channel arrays on metallic bipolar plate using multifunctional cathode

Cited by 16 publications

References 24 publications

Flow Analysis Based on Cathodic Current Using Different Designs of Channel Distribution In PEM Fuel Cells

Flow Analysis Based on Cathodic Current Using Different Designs of Channel Distribution In PEM Fuel Cells

Research on Stagger Coupling Mode of Pulse Duration and Tool Vibration in Electrochemical Machining

Electrochemical Machining Multiple Slots of Bipolar Plates with Tool Vibration

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