碱水制氢电解槽极板通道中气泡的生成及演化性质

doi:10.11949/0438-1157.20250180

摘要/Abstract

摘要：

碱水制氢电解槽极板上气泡的生成和合并会改变电解液的流动状态，影响电解液的速度场、温度场分布，导致局部过电流和热点出现，进而降低电解槽的电解效率。采用水平集耦合流体体积（CLS-VOF）数值技术对极板通道中的气液两相流动状态进行了模拟研究，考察了气泡在极板通道表面上的生成、成长和脱落过程，以及气泡之间的合并规律，研究了电流密度、电解液流量和通道截面形状对极板通道中含气率、表面气体覆盖率和压力降的影响。结果表明，气泡合并尺寸、含气率、表面气体覆盖率随着电流密度增大而增大，随着电解液流量增大而减小。

关键词: 碱水电解槽, 制氢, 双极板, 通道, 气泡, 两相流

Abstract:

In alkaline water electrolyzers, the generation and coalescence of gas bubbles on the bipolar plates will change the flow pattern of electrolytes and affect the velocity and temperature fields of the electrolytes, leading to local overcurrent and hot spots, further reducing the overall electrolysis efficiency. The gas-liquid two-phase flow state in the plate channel is simulated by the level set coupled volume of fluid (CLS-VOF) numerical technique. The generation, growth, and detachment of individual bubbles on the surface of the bipolar plate and the coalescence between bubbles are investigated in detail. The effects of current density, electrolyte flow rate, and cross-sections of channels on the gas content, surface gas coverage, and pressure drop in the polar plate channel are explored. The results showed that the bubble size, gas content, and surface gas coverage increase with the increase of current density and decrease with the growth of electrolyte flow rate.

Key words: alkaline water electrolyzers, hydrogen production, bipolar plates, channel, bubble, two-phase flow

中图分类号:

TQ 028.8

邹家庆, 张肇钰, 张建国, 张博宇, 刘定胜, 毛庆, 王挺, 李建军. 碱水制氢电解槽极板通道中气泡的生成及演化性质[J]. 化工学报, 2025, 76(9): 4786-4799.

Jiaqing ZOU, Zhaoyu ZHANG, Jianguo ZHANG, Boyu ZHANG, Dingsheng LIU, Qing MAO, Ting WANG, Jianjun LI. Generation and evolution of bubbles in channels of bipolar plates of alkaline water electrolyzers for producing hydrogen[J]. CIESC Journal, 2025, 76(9): 4786-4799.

图/表 26

图1 碱性水电解槽的结构示意图：(a)极板模型；(b)边界条件；(c)结构尺寸

Fig.1 Schematic diagrams of the simulations: (a) polar plate model; (b) boundary conditions; (c) geometry dimension

表1 物性参数及操作条件（电流密度为0.5 A/cm2）

Table 1 Physical parameters and operation conditions （current density of 0.5 A/cm2）

参数	数值
工作温度/K	298
工作压力/Pa	101325
KOH溶液密度^[26]/（kg/m³）	1216.11
O₂密度/（kg/m³）	1.29
5 mol/L KOH动力黏度^[27]/（kg/(m·s)）	1.6549×10^-3
O₂动力黏度/（kg/(m·s)）	1.919×10^-5
表面张力^[28]/（N/m）	0.0871
KOH入口流量/（ml/min）	15
出口表压/Pa	0
接触角^[29]/（°）	150

图2 不同通道截面的模型示意图

Fig.2 Schematic diagram of different types of channel structures

表2 0.7 ms时B4及B5处生成的气泡大小随网格尺寸的变化

Table 2 Variation of bubble size with mesh size at B4 and B5 at 0.7 ms

网格尺寸/mm	网格总数/个	B4气泡y方向尺寸/mm	B5气泡y方向尺寸/mm
0.030	528160	0.475	0.474
0.025	741280	0.480	0.488
0.020	2000000	0.483	0.482

图3 气泡形状的实验[30]（左侧）与仿真（右侧）比较

Fig.3 Comparisons of bubble shapes between the experiment[30] (left) and the present simulation (right) for model validation

图4 B1处气泡的生成过程（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 1.0）

Fig.4 Bubble generation process at orifice B1 (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 1.0)

图5 B1处气泡的生成过程（J = 0.5 A/cm2，QL = 5 ml/min，θ = 150°，W/H = 1.0）

Fig.5 Bubble generation process at orifice B1 (J = 0.5 A/cm2, QL = 5 ml/min, θ = 150°, W/H = 1.0)

图6 电流密度及电解液流量变化对B1处气泡脱离时间的影响（W/H = 1.0）

Fig.6 Effects of current density and electrolyte flow rate on the detachment time of bubbles at B1 hole (W/H = 1.0)

图7 B1处气泡的生成过程（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 0.5）

Fig.7 Generation process of a bubble at orifice B1 (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 0.5)

图8 B1处气泡的生成过程（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 2.0）

Fig.8 Generation process of a bubble at orifice B1 (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 2.0)

图9 B1处气泡的生成过程（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，梯形截面通道）

Fig.9 Generation process of a bubble at orifice B1 (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, trapezoidal cross-section channel)

图10 气泡体积随时间的变化（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 1.0）

Fig.10 Variation of bubble volume with time (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 1.0)

图11 B1~B9处气泡脱离和合并过程（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 1.0）

Fig.11 Detachment and coalescence of bubbles at orifices B1—B9 (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 1.0)

图12 气泡体积随时间的变化（J = 3.0 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 1.0）

Fig.12 Variation of bubble volume with time (J = 3.0 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 1.0)

图13 B1~B9处气泡脱离和合并过程（J = 3.0 A/cm2，QL = 15 ml/min，θ = 150°，W/H = 1.0）

Fig.13 Detachment and coalescence of bubbles at orifices B1—B9 (J = 3.0 A/cm2, QL = 15 ml/min, θ = 150°, W/H = 1.0)

图14 气泡体积随时间的变化（J = 0.5 A/cm2，QL = 10 ml/min，θ = 150°，W/H = 1.0）

Fig.14 Detachment and coalescence of bubbles at B6 (J = 0.5 A/cm2, QL = 10 ml/min, θ = 150°, W/H = 1.0)

图15 气泡体积随时间的变化（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°）

Fig.15 Change in bubble volume with time (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°)

图16 不同电流密度下含气率随时间的变化（W/H = 1.0，QL = 15 ml/min，θ = 150°）

Fig.16 Variation of gas fraction with time under different current densities (W/H = 1.0, QL = 15 ml/min, θ = 150°)

图17 不同电流密度下GDL表面气体覆盖率随时间的变化（W/H = 1.0，QL = 15 ml/min，θ = 150°）

Fig.17 Variation of surface gas fraction on GDLwith time under different current densities (W/H = 1.0, QL = 15 ml/min, θ = 150°)

图18 压力降随时间的变化（W/H = 1.0，QL = 15 ml/min，θ = 150°）

Fig.18 Pressure drop over time (W/H = 1.0, QL = 15 ml/min, θ = 150°)

图19 不同电解液流量下含气率随时间的变化（W/H = 1.0，J = 0.5 A/cm2，θ = 150°）

Fig.19 Variation of gas fraction with time under different electrolyte flow rates (W/H = 1.0, J = 0.5 A/cm2, θ = 150°)

图20 不同电解液流量下表面气体覆盖率随时间的变化（W/H = 1.0，J = 0.5 A/cm2，θ = 150°）

Fig.20 Variation of surface gas fraction on GDL with time under different electrolyte flow rates (W/H = 1.0, J = 0.5 A/cm2, θ = 150°)

图21 压力降随时间的变化（W/H = 1.0，J = 0.5 A/cm2，θ = 150°）

Fig.21 Pressure drop over time (W/H = 1.0, J = 0.5 A/cm2, θ = 150°)

图22 不同通道截面形状下含气率随时间的变化（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°）

Fig.22 Variation of gas fraction with time in channels with different cross-sections (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°)

图23 不同通道截面形状下表面气体覆盖率随时间的变化（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°）

Fig.23 Variation of surface gas coverage with time in channels with different cross-sections (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°)

图24 压力降随时间的变化（J = 0.5 A/cm2，QL = 15 ml/min，θ = 150°）

Fig.24 Pressure drop over time (J = 0.5 A/cm2, QL = 15 ml/min, θ = 150°)

参考文献 30

[1]	Shimada H, Yamaguchi T, Kishimoto H, et al. Nanocomposite electrodes for high current density over 3 A·cm^-2 in solid oxide electrolysis cells[J]. Nature Communications, 2019, 10(1): 5432.
[2]	Hauch A, Küngas R, Blennow P, et al. Recent advances in solid oxide cell technology for electrolysis[J]. Science, 2020, 370(6513): eaba6118.
[3]	Flamm B, Peter C, Büchi F N, et al. Electrolyzer modeling and real-time control for optimized production of hydrogen gas[J]. Applied Energy, 2021, 281: 116031.
[4]	Qu W J, Zhang J, Jiang R H, et al. An energy storage approach for storing surplus power into hydrogen in a cogeneration system[J]. Energy Conversion and Management, 2022, 268: 116032.
[5]	Shiva Kumar S, Lim H. An overview of water electrolysis technologies for green hydrogen production[J]. Energy Reports, 2022, 8: 13793-13813.
[6]	Okolie J A, Patra B R, Mukherjee A, et al. Futuristic applications of hydrogen in energy, biorefining, aerospace, pharmaceuticals and metallurgy[J]. International Journal of Hydrogen Energy, 2021, 46(13): 8885-8905.
[7]	Naqvi S A H, Taner T, Ozkaymak M, et al. Hydrogen production through alkaline electrolyzers: a techno-economic and enviro-economic analysis[J]. Chemical Engineering & Technology, 2023, 46(3): 474-481.
[8]	David M, Ocampo-Martínez C, Sánchez-Peña R. Advances in alkaline water electrolyzers: a review[J]. Journal of Energy Storage, 2019, 23: 392-403.
[9]	Koumi Ngoh S, Njomo D. An overview of hydrogen gas production from solar energy[J]. Renewable and Sustainable Energy Reviews, 2012, 16(9): 6782-6792.
[10]	Dincer I, Acar C. Review and evaluation of hydrogen production methods for better sustainability[J]. International Journal of Hydrogen Energy, 2015, 40(34): 11094-11111.
[11]	Hreiz R, Abdelouahed L, Fünfschilling D, et al. Electrogenerated bubbles induced convection in narrow vertical cells: PIV measurements and Euler-Lagrange CFD simulation[J]. Chemical Engineering Science, 2015, 134: 138-152.
[12]	Majasan J O, Cho J I S, Dedigama I, et al. Two-phase flow behaviour and performance of polymer electrolyte membrane electrolysers: electrochemical and optical characterisation[J]. International Journal of Hydrogen Energy, 2018, 43(33): 15659-15672.
[13]	Boissonneau P, Byrne P. An experimental investigation of bubble-induced free convection in a small electrochemical cell[J]. Journal of Applied Electrochemistry, 2000, 30(7): 767-775.
[14]	Abdelouahed L, Valentin G, Poncin S, et al. Current density distribution and gas volume fraction in the gap of lantern blade electrodes[J]. Chemical Engineering Research and Design, 2014, 92(3): 559-570.
[15]	El-Askary W A, Sakr I M, Ibrahim K A, et al. Hydrodynamics characteristics of hydrogen evolution process through electrolysis: numerical and experimental studies[J]. Energy, 2015, 90: 722-737.
[16]	Aldas K. Application of a two-phase flow model for hydrogen evolution in an electrochemical cell[J]. Applied Mathematics and Computation, 2004, 154(2): 507-519.
[17]	Abdelouahed L, Hreiz R, Poncin S, et al. Hydrodynamics of gas bubbles in the gap of lantern blade electrodes without forced flow of electrolyte: experiments and CFD modelling[J]. Chemical Engineering Science, 2014, 111: 255-265.
[18]	Arbabi F, Montazeri H, Abouatallah R, et al. Three-dimensional computational fluid dynamics modelling of oxygen bubble transport in polymer electrolyte membrane electrolyzer porous transport layers[J]. Journal of the Electrochemical Society, 2016, 163(11): F3062-F3069.
[19]	Vachaparambil K J, Einarsrud K E. Numerical simulation of continuum scale electrochemical hydrogen bubble evolution[J]. Applied Mathematical Modelling, 2021, 98: 343-377.
[20]	Zarghami A, Deen N G, Vreman A W. CFD modeling of multiphase flow in an alkaline water electrolyzer[J]. Chemical Engineering Science, 2020, 227: 115926.
[21]	Mat M D, Aldas K. Application of a two-phase flow model for natural convection in an electrochemical cell[J]. International Journal of Hydrogen Energy, 2005, 30(4): 411-420.
[22]	Mat M D, Aldas K, Ilegbusi O J. A two-phase flow model for hydrogen evolution in an electrochemical cell[J]. International Journal of Hydrogen Energy, 2004, 29(10): 1015-1023.
[23]	Mandin P, Hamburger J, Bessou S, et al. Modelling and calculation of the current density distribution evolution at vertical gas-evolving electrodes[J]. Electrochimica Acta, 2005, 51(6): 1140-1156.
[24]	Eigeldinger J, Vogt H. The bubble coverage of gas-evolving electrodes in a flowing electrolyte[J]. Electrochimica Acta, 2000, 45(27): 4449-4456.
[25]	Li Y F, Kang Z Y, Mo J K, et al. In-situ investigation of bubble dynamics and two-phase flow in proton exchange membrane electrolyzer cells[J]. International Journal of Hydrogen Energy, 2018, 43(24): 11223-11233.
[26]	Gilliam R J, Graydon J W, Kirk D W, et al. A review of specific conductivities of potassium hydroxide solutions for various concentrations and temperatures[J]. International Journal of Hydrogen Energy, 2007, 32(3): 359-364.
[27]	Sipos P M, Hefter G, May P M. Viscosities and densities of highly concentrated aqueous MOH solutions (M⁺ = Na⁺, K⁺, Li⁺, Cs⁺, (CH₃)₄N⁺) at 25.0 ℃[J]. Journal of Chemical & Engineering Data, 2000, 45(4): 613-617.
[28]	Dunlap P M, Faris S R. Surface tension of aqueous solutions of potassium hydroxide[J]. Nature, 1962, 196: 1312-1313.
[29]	German S R, Edwards M A, Ren H, et al. Critical nuclei size, rate, and activation energy of H₂ gas nucleation[J]. Journal of the American Chemical Society, 2018, 140(11): 4047-4053.
[30]	Kong G, Mirsandi H, Buist K A, et al. Oscillation dynamics of a bubble rising in viscous liquid[J]. Experiments in Fluids, 2019, 60(8): 130.