Browsing by Author "Koorata, P.K."

Now showing 1 - 20 of 31

A phase-dependent constitutive model to predict cyclic electrical conductivity in fuel cell gas diffusion media
(Elsevier B.V., 2022) Shinde, U.; Koorata, P.K.
Structure-property relation in fuel cell gas diffusion layer (GDL) is a dependent function of its constituents. The bulk electrical conductivity of these layers is known to be relative density function varying due to external force or cell operating conditions. To locally predict the changes due to complex working conditions, an accurate model that predicts the nonlinearity of GDLs is highly desirable. To this end, this article proposes a material model that is phenomenologically derived to address the cyclic electrical conductivity of GDLs. Functional variables are taken to operate on porosity variation, fiber contact density, and fiber dislocation parameters. In the presence of these parameters, the results illustrate nonlinear conductivity variation with the magnitude of applied cyclic compressive load. Through successive loading-unloading, the porous structure is modeled to reach a steady-state reflecting stable conductivity-stress behavior for the constant stress limit. An interesting behavior of GDL can be captured where conductivity reduces as compressive load exceeds a threshold limit called break stress due to fiber breakages or dislocations. A greater applicability of this model may lie in mapping localized in-situ response of GDLs under cyclic operations. © 2022 Elsevier B.V.
A review on transport properties and performance of commercial and novel membranes for anion exchange membrane water electrolyser
(Elsevier Ltd, 2025) Naik, V.V.; Koorata, P.K.; Nuggehalli Sampathkumar, S.N.; Van herle, J.
The growing demand for renewable-powered hydrogen drives interest in water electrolysis, making anion exchange membrane water electrolysis (AEMWE) an emerging technology. The anion exchange membrane (AEM) integrates the benefits of both the proton exchange membrane (PEMs) and alkaline water electrolysis (AWEs), enabling the use of cost-efficient transition metal catalysts instead of precious metals and operating in distilled water or low-concentration KOH electrolytes, thereby reducing corrosion issues. Like PEMWE, AEMWE offers high-purity hydrogen, broader material compatibility, and reduced system costs. Moreover, it offers a low-temperature alternative to solid oxide electrolysis (SOECs), simplifying system integration. Despite these benefits, large-scale adoption is limited by several challenges, including limited alkaline stability of membranes, trade-offs between ionic conductivity and durability, insufficient long-term stability of PGM-free catalysts, and elevated interfacial resistance at membrane electrode assembly (MEA) and porous transfer layer (PTL) junctions. These constraints are reflected in conventional AEMs, which typically exhibit limited conductivities of ∼100 mS/cm at 60–80 °C with lifetimes of under 1000 h. In contrast, commercial membranes demonstrate higher conductivities of ∼150 mS/cm, enabling improved performance, delivering current densities of 0.8–1.2 A/cm2 at voltages of 1.8–2.0 V. Recent developments in novel AEMs have further enhanced both current density and stability by 20–30 %, achieving >1.6 A/cm2 and >1500 h under optimised conditions. However, the long-term durability of PGM-free catalysts remains a critical limitation. In addition to technical performance, AEMWE also presents economic advantages over other electrolysis technologies. This review systematically evaluates commercial membranes, including Tokuyama, Fumatech, Orion, Aemion, Sustainion, and Piperion, alongside emerging alternatives. Key aspects such as chemical structures, ion transport properties, electrochemical performance, cost analysis of commercial membranes, degradation mechanisms, and advances in MEAs are examined. The role of PGM and PGM-free catalysts in improving efficiency and reducing costs is also highlighted. Several novel membranes demonstrate performance comparable to or exceeding commercial standards, indicating strong potential for future commercialisation. Finally, the review identifies critical research gaps, including the need for alkaline-stable polymers, durable PGM-free catalysts, optimised MEA/PTL architectures to mitigate interfacial resistance, and standardised long-term testing protocols, which are essential for transitioning AEMWE from laboratory studies to scalable, cost-effective hydrogen production systems. © 2025 Hydrogen Energy Publications LLC
Case study for contact pressure improvisation with graded implant material in articular cartilages of knee joint
(Korean Society of Mechanical Engineers, 2021) Raju, V.; Koorata, P.K.; Kamat, Y.
In this study, the effect of graded design in comparison to homogeneous cartilage material is investigated for contact pressure distribution in the human knee joint. Knee implants are assumed a homogeneous material. In reality, cartilages are not homogeneous, and to replicate the heterogeneity of cartilages, a graded design is proposed. Simulation results show improved contact pressure distribution in the knee joint due to the graded composition of cartilages. The results are helpful in designing a new class of implant materials. © 2021, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature.
Combined influence of concentration-dependent properties, local deformation and boundary confinement on the migration of Li-ions in low-expansion electrode particle during lithiation
(Elsevier Ltd, 2022) Kausthubharam, n.; Koorata, P.K.; Panchal, S.; Fraser, R.; Fowler, M.
In this article, a low expansion electrode particle is investigated for mechanical stresses during lithiation with intrinsic and extrinsic factors included. The stress states are estimated with local deformation, concentration dependent properties, and external constraints. It is observed that lithiation of an unconstrained electrode particle lead to reduced concentration gradient of Li-ions with increase in stress magnitude for a case where the particle show concentration dependent stiffening response. Whereas, the constrained expansion of the same electrode particle result in reduced and elevated concentration gradient at near-field and far-field locations, respectively. Influence of charging rate is also reported wherein limiting stress (threshold limit) is observed with increasing charging rate. Further, at elevated charging rates, a drastic reduction in concentration gradient is observed at the surface of the electrode particle. © 2022 Elsevier Ltd
Compressive cyclic response of PEM fuel cell gas diffusion media
(Elsevier Ltd, 2021) Koorata, P.K.; Bhat, S.D.
The fuel cell gas diffusion media (GDM) is a highly porous carbon-fiber-reinforced thin composite layer. The experimental response of these materials is observed to be highly nonlinear at low-stress levels. The cyclic mechanical response of GDM is investigated in terms of stiffness and damage parameters. The prediction of the state of deformation in GDM is vital in relating GDM's properties to ohmic and transport losses. To this end, a compressible form of the phenomenological model is proposed to capture the experimental cyclic response accurately. The model is constituent dependent; that is, the cumulative cyclic stress-strain response of GDM is a function of individual constituent phases present in the material. These individual constituents are porous matrix and reinforced fibers. The model hence derived for a typical GDM material, can predict residual strain, hysteresis, and damage quotient associated with the stress softening. This advanced model is implemented in the numerical domain to evaluate the response of the polymer electrolyte fuel cell (PEFC) unit cell. The stress-strain distribution fields are analyzed and compared with those of conventional GDM models. The results point to a remarkable deviation from the conventional notion of structural analysis. © 2020 Hydrogen Energy Publications LLC
Computational assessment on the impact of collagen fiber orientation in cartilages on healthy and arthritic knee kinetics/kinematics
(Elsevier Ltd, 2023) Raju, V.; Koorata, P.K.
Background: The inhomogeneous distribution of collagen fiber in cartilage can substantially influence the knee kinematics. This becomes vital for understanding the mechanical response of soft tissues, and cartilage deterioration including osteoarthritis (OA). Though the conventional computational models consider geometrical heterogeneity along with fiber reinforcements in the cartilage model as material heterogeneity, the influence of fiber orientation on knee kinetics and kinematics is not fully explored. This work examines how the collagen fiber orientation in the cartilage affects the healthy (intact knee) and arthritic knee response over multiple gait activities like running and walking. Methods: A 3D finite element knee joint model is used to compute the articular cartilage response during the gait cycle. A fiber-reinforced porous hyper elastic (FRPHE) material is used to model the soft tissue. A split-line pattern is used to implement the fiber orientation in femoral and tibial cartilage. Four distinct intact cartilage models and three OA models are simulated to assess the impact of the orientation of collagen fibers in a depth wise direction. The cartilage models with fibers oriented in parallel, perpendicular, and inclined to the articular surface are investigated for multiple knee kinematics and kinetics. Findings: The comparison of models with fiber orientation parallel to articulating surface for walking and running gait has the highest elastic stress and fluid pressure compared with inclined and perpendicular fiber-oriented models. Also, the maximum contact pressure is observed to be higher in the case of intact models during the walking cycle than for OA models. In contrast, the maximum contact pressure is higher during running in OA models than in intact models. Additionally, parallel-oriented models produce higher maximum stresses and fluid pressure for walking and running gait than proximal-distal-oriented models. Interestingly, during the walking cycle, the maximum contact pressure with intact models is approximately three times higher than on OA models. In contrast, the OA models exhibit higher contact pressure during the running cycle. Interpretation: Overall, the study indicates that collagen orientation is crucial for tissue responsiveness. This investigation provides insights into the development of tailored implants. © 2023 IPEM
Computational evaluation of the effect of femoral component curvature on the mechanical response of the UHMWPE tibial insert in total knee replacement implants
(Elsevier Ltd, 2022) Raju, V.; Koorata, P.K.
Total knee replacement (TKR) surgery is done on individuals with end-stage osteoarthritis to restore knee function and alleviate joint discomfort. There have been recent developments in the design of customized implants based on patient-specific data obtained from MRI scans and subsequent image processing techniques. Here curvature of the femoral component plays an important role in effective implant design. Therefore, the objective here is to investigate the influence of this curvature of the femoral component on the mechanical response of the bearing component. A 3D finite element knee implant model with a circular and an elliptical femoral component is developed and investigated for gait kinetics and kinematics. Responses such as contact pressure, stresses, strains, and wear produced on the tibial insert are estimated throughout the gait cycle. These findings suggest that the elliptical femoral component generates less contact pressure on the tibial insert than its circular counterpart. It is also inferred that too much variation in this curvature is not recommended as it may affect the patient's comfort level. In addition, the wear of the tibial insert is computed based on the contact pressure created by both knee implant models. Our study suggests an optimum value for the curvature and the comfort level of the patients over the existing knee implant designs. © 2022 Elsevier Ltd. All rights reserved.
Deformation Mechanics of Fuel Cell Gas Diffusion Layer: Cyclic Response and Constitutive Model
(Institute of Physics, 2022) Koorata, P.K.
The deformation mechanics of a typical gas diffusion layer using experimental and advanced modelling technique is reported. The experimental cyclic response is observed similar to pseudo-elastic materials with highly nonlinear loading/unloading. The cyclic compressive mechanical response of gas diffusion layer (GDL) is modelled to be the outcome of cumulative changes in deformation kinematics of matrix and fiber fractions. The individual mechanisms necessitating the energy dissipation, residual strain, and stress softening during cyclic mechanical response are related to nonlinear hyperelastic matrix with the damage function and inelastic activation function at the interface of constituents. The model predicts highly nonlinear elastic loading, residual strain, hysteresis, and damage quotient associated with stress softening as a function of several cycles. The significant takeaway from this study is in terms of quantifying strength, inelastic nature of individual constituents. The proposed model is simulated for low-level altering stresses of up to twenty cycles. The results show the build-up of residual strains and hysteresis as a function of fuel cell clamping pressure. © 2022 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.
Design of novel test rig for prosthetic finger distal interphalangeal and phalanx strengths
(Wolters Kluwer Health, 2025) Madhu Mohan, R.; Kattimani, S.; Koorata, P.K.; Girisha, C.
Testing is one of the most significant phases of any engineering process, the last process followed by conceptualization, designing, and fabricating. If the testing outcomes are not genealogy sensible measurables, then eventually it calls for a redesign overhaul. Existing testing equipment to analyze the load and failures are conventional digital universal testing machines with minimum jigs and fixtures. In addition, the existing fixtures cannot be adapted to the anatomy of a human finger. Consequently, the present work explores the best possible design of a jig for testing the naturally articulated movement of a human finger (prosthetic wear-on). Furthermore, the present jig design checks a wide range of parameters such as freedom of motion, a path along with curvature, load, failures, and intermittent positions of applied load, which is adaptable to existing universal testing machines available for broader applications. © 2024 International Society for Prosthetics and Orthotics.
Development of Fast Charging Control Algorithm for Electric Vehicles
(Institute of Electrical and Electronics Engineers Inc., 2022) Yadav, A.; Koorata, P.K.; Dastagiri Reddy, B.D.
The rapid market integration of electric vehicles has resulted in an increase in the interest of fast charging technology. One of the major concerns associated with fast charging is safety of the operation. Fast charging involves effective communication between DC charger and battery management system through the charging control algorithm embedded in the vehicle controller unit. The development of such control strategy requires interdisciplinary cooperation between different participants. A lack of system understanding can lead to safety hazards. Here in this paper, we have developed a charging control strategy for CHAdeMO DC charger using model-based development which is a better method than conventional embedded C coding and its working is shown in a starter model of DC charger in STATEFLOW. Â© 2022 IEEE.
Electrical/flow heterogeneity of gas diffusion layer and inlet humidity induced performance variation in polymer electrolyte fuel cells
(Elsevier Ltd, 2023) Shinde, U.; Koorata, P.K.; Padavu, P.
A three-dimensional single-flow channel computational model is used to investigate the performance characteristics of polymer electrolyte fuel cells (PEFC). The combined influence of non-uniform interfacial contact resistance (ICR) and inlet relative humidity (RH), along with the heterogeneous flow properties of the gas diffusion layer (GDL) on the PEFC performance is evaluated. The study considers combinations of full and partial humidification of anode and cathode reactants. Results reveal heterogeneous GDL with non-uniform ICR distribution results in a slight ∼4.4% reduction in current density at 0.3V compared to the homogeneous case. However, under same electrical/flow heterogeneities, the current density is observed to increase by ∼19% to ∼1.3A/cm2 under fully humidified anode and partially humidified cathode (i.e., RHa|RHc = 100%|60%) as compared to ∼1.1A/cm2 under symmetric RHa|RHc = 100%|100%. Interesting observations are made on the temperature distribution and cathodic water fractions. The variation in anodic inlet humidity is observed to have no impact on temperature distribution in the membrane, whereas variation in cathodic inlet humidity is effective in reducing the temperature in the channel regime with a 4K (kelvin) difference among all the cases. It is noted here that the overpotential map is not an indicator for performance loss, at least at full inlet humidity. This parameter is observed to depend on water concentration in the cathode. The study provides a detailed analysis of the distribution of reactant mass fraction, water concentration, current density, temperature, cathodic overpotential, and cell performance for all the simulated cases. © 2022 Hydrogen Energy Publications LLC
Enhanced hydronium ion diffusion in proton exchange membranes reinforced with multilayer graphene oxide: new insights into water retention and ion mobility using molecular dynamics simulation
(Royal Society of Chemistry, 2025) Varshney, S.K.; Koorata, P.K.
Graphene oxide (GO) reinforced perfluorosulfonic acid (PFSA) based proton exchange membranes (PEMs) show enhanced ion diffusion resulting in elevated polymer electrolyte fuel cell (PEFC) performance. However, the mechanisms by which GO influences water dynamics and ion (hydronium) transport are relatively less explored in the literature. In addition, it is expected that the interlayer spacing of multilayer GO plays a crucial role in promoting ion mobility. To this end, this research article explores the possibility of providing new insights into the water/ion dynamics as well as identifying the impact of interlayer spacing of GO on the ion diffusion. Molecular dynamics (MD) simulation is implemented to elucidate the behaviour of multilayer-GO with PFSA structure and to examine the interactions between functional groups (epoxy and hydroxyl) on the GO surface with water molecules and hydronium ions. The retention of water molecules adjacent to the multilayer-GO plays a crucial role in forming transport channels that significantly enhance ion mobility within the membrane structure. The optimal interlayer spacing of 9.5 Å is identified as the critical threshold value where ion diffusion is observed at its peak. In comparison with pristine Nafion®, the ion (hydronium) diffusion coefficient in the multilayer-GO with PFSA polymer shows an improvement of ?17% and ?30% at 300 K and ?9% and ?12% at 350 K for hydration levels (?) of 13 and 20, respectively. This journal is © 2025 The Royal Society of Chemistry
Evaluating the PEM fuel cell performance under accelerated creep of sealants
(Elsevier Ltd, 2025) Kumar, V.; Koorata, P.K.
The physical properties of sealants could be crucial in affecting the performance and longevity of the polymer electrolyte membrane fuel cell (PEMFC). As the sealants' physical properties are temperature and stress-dependent due to their inherent viscoelasticity, their creep response must be explored. The numerical study presented in this article emphasizes evaluating the performance of low-temperature PEMFC (LT-PEMFC) influenced by polytetrafluoroethylene (PTFE) sealants' accelerated creep characterized by the compliance curves (MC-65). The performance of a 3D single-channel PEMFC model is investigated and compared for two cases, wherein the first case focused on PEMFC performance without sealant creep, and the second case incorporated sealants' accelerated creep to assess PEMFC performance. The detailed observation of reactant transport characteristics demonstrates that there is a substantial decline in oxygen reduction reaction (ORR) at the cathode gas diffusion layer (GDL) and cathode catalyst layer (CL) in the case of sealants' accelerated creep. Further, liquid saturation at the cathode GDL is observed to increase significantly, leading to a reduction in the performance of the cell. It is further conveyed that the current density for case 1 (without creep) and case 2 (sealants' accelerated creep) are 1.309655 and 1.041806 Acm?2, respectively, at a cell voltage of 0.4 V. The present study, therefore, addresses the viable interaction between fuel cell performance and the sealants’ accelerated creep characteristics. © 2025 Hydrogen Energy Publications LLC
Geometrical pole shape optimization of an outer rotor synchronous reluctance motor for output torque enhancement
(Institute of Electrical and Electronics Engineers Inc., 2024) Chauhan, V.K.S.; Koorata, P.K.
This article explores optimizing design for Permanent magnet (PM) free outer rotor synchronous reluctance machines to be used as in-wheel motors for electric vehicles. The primary objective is enhancing torque output by systematically analyzing various rotor pole shapes and parameters such as pole depth, arc angles, rib thickness, channel width, and fillet radii. These parameters were studied on four different types of pole shapes. Using ANSYS Maxwell software, the analysis is performed on an outer rotor motor with a diameter of 190 mm and a rated speed of 1200 RPM. The results indicate that outer rotor machines with configurations such as an inner arc angle of 9 degrees and an outer arc angle of 24 degrees exhibit optimal torque output for pole shape 1. Moreover, the study reveals that an increase in pole depth (SB) corresponds to an increase in torque output, while rib thickness reduces torque output. Additionally, the research explores the impact of fillet radii on torque performance. This study provides the effects of essential features of critical design parameters on reluctance torque for maximizing average torque in outer rotor motors utilized in EV applications. Â© 2024 IEEE.
Impact of mechanical stiffening and softening on the spatial distribution of lithium ions in spherical electrode particle under galvanostatic charging
(John Wiley and Sons Ltd, 2021) Kausthubharam, n.; Koorata, P.K.; Chandrasekaran, N.
This article investigates the lithiation of low-expansion electrode particles with concentration-dependent properties. The conventional electrochemical coupled stress equations do not take into account concentration dependency, especially for particles with a low volume of expansion, as they are assumed to have no impact on the lithium-ion (Li-ion) migration. However, considerable changes are observed in the present study when this factor is included. The Li-ion concentration gradient is observed to decrease with stiffening and increase with softening in an electrode particle. The stresses at the center of the particle increase with stiffening and reduce with the softening. It is observed that the effect of concentration-dependent elastic modulus on the concentration gradient of lithium ions at the surface of the particle is more prominent at higher charging rates. The stresses in the electrode particle are observed to increase in proportion to an increase in the charging rate up to a critical limit beyond which its magnitude reduces. © 2021 John Wiley & Sons Ltd.
Influence of material heterogeneity on the mechanical response of articulated cartilages in a knee joint
(SAGE Publications Ltd, 2022) Raju, V.; Koorata, P.K.
Structurally, the articular cartilages are heterogeneous owing to nonuniform distribution and orientation of its constituents. The oversimplification of this soft tissue as a homogeneous material is generally considered in the simulation domain to estimate contact pressure along with other physical responses. Hence, there is a need for investigating knee cartilages for their actual response to external stimuli. In this article, impact of material and geometrical heterogeneity of the cartilage is resolved using well known material models. The findings are compared with conventional homogeneous models. The results indicate vital differences in contact pressure distribution and tissue deformation. Further, this study paves way for standardizing material models to extract maximum information possible for investigating knee mechanics with variable geometry and case specific parameters. © IMechE 2022.
Investigation of the thermal performance of biomimetic minichannel-based liquid-cooled large format pouch battery pack
(Elsevier Ltd, 2024) Kausthubharam, n.; Koorata, P.K.; Panchal, S.; Fraser, R.; Fowler, M.
This article presents a diagonal-type minichannel-based thermal management system for a 20 Ah pouch cell battery. An optimal thermal strategy is suggested by numerically investigating the cooling performance of the proposed design for various structural and operational parameters. Besides the design, mini-channel optimization is observed to have played a significant role in pressure drop and temperature. An operational parametric study recommends an inlet temperature of 25 °C and a flow rate of 12.5 cm3/s for the liquid coolant for optimal pouch cell performance. The enhancement of temperature distribution uniformity is noted to diminish at higher cooling fluid flow rates. Further, a comparison with existing literature revealed a 75 % increase in temperature homogeneity across the pouch cell. The feasibility of the proposed design with an optimized cooling framework at the module level is demonstrated for the 43 V battery pack. The thermal system maintained the maximum temperature in the pack 20 % below the upper limit of the recommended range for Li-ion cells. © 2024 Elsevier Ltd
Investigation on the Influence of Soft Tissues in Knee Joint on Load Transfer Mechanism during the Gait Cycle
(American Institute of Physics, 2024) Raju, V.; Koorata, P.K.
Soft tissues keep the human knee joint stable and serve an essential function in limiting motion during daily activities.The goal of this work is to investigate the influence of knee components during a person subjected to walking. A 3D finite element model of a knee joint used for the analysis. The knee kinetics (forces and rotation) during the stance phase of a gait in all degrees of freedom are incorporated into the model. The contact pressure, effective Lagrange strain, maximum shear stress, effective stress and total displacement generated on all the soft tissues are compared. The meniscus shows a more excellent value in all areas concerning other tissues, and for stress values, it is 4 to 5 times greater. The result also indicates that the contact pressure of the tibial cartilage is higher than the femur cartilage throughout the cycle. However, the effective Lagrange strain of femur cartilage is higher than tibial cartilage during the initial phase of the cycle and later declined. These values might help develop comprehensive computational tools to help us better understand the knee injury and disease causes. Â© 2024 American Institute of Physics Inc.. All rights reserved.
Low stress creep response of PTFE sealants applied to PEM fuel cells
(John Wiley and Sons Inc, 2024) Kumar, V.; Koorata, P.K.
Viscoelastic properties of polytetrafluoroethylene (PTFE) play a crucial role in forecasting its long-term behavior in engineering applications. An attempt is made to explore the viscoelastic properties of PTFE sealants that are utilized in polymer electrolyte membrane fuel cell (PEMFC). It is to be noted that PTFE sealants are vulnerable to creep under constant loading at elevated temperatures. Moreover, the creep of sealants will lead to leakage of reactants from the cell, which affects the performance of PEMFC. PTFE is an excellent choice as a sealant material in low-temperature polymer electrolyte membrane fuel cell (LT-PEMFC), which operates in the temperature range of 60–80°C. PTFE can be prominently used as sealants in high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC), as it possesses no significant change in its physical properties within the temperature range of −150 to 300°C along with the working conditions of HT-PEMFC. In LT-PEMFC, the sealants will typically be subjected to low stresses in the range of 1–5 MPa. In this article, the creep response of PTFE sealant material is extensively studied at various temperatures of 25 (room temperature), 35, 45, 55, and 65°C and at three stress levels of 2, 3, and 4 MPa. The time–temperature superposition principle is utilized to develop master curve at a reference temperature of 25°C, to forecast long-term creep characteristics of PTFE sealants. Moreover, the master curve for creep compliance is developed for 4.5 h. © 2024 Wiley Periodicals LLC.
Model based evaluation of water management and membrane hydration in polymer electrolyte fuel cell with reactant flow-field gradients
(Elsevier Ltd, 2023) Padavu, P.; Koorata, P.K.; Kattimani, S.
Efficient water management and intrinsic membrane hydration are critical requirements of polymer electrolyte fuel cells (PEFC) under high load current. PEFC undergoes performance loss during high current demand due to reactant depletion, water flooding, and membrane hydration. Hence, water management and membrane hydration become vital for endured life of PEFC itself. Further, flow field optimization assists in overcoming the critical transport factors affecting the PEFC performance. A model-based approach is envisioned to understand effective water management wherein reactant flow channel gradients are designed to investigate its advantages and limitations. Here, we show efficient water management of these cells at high current demand where reactant distribution governs the cell characteristics. On comparing the current density distribution of the flow field designs under both Maximum Humid and Partial Humid inlet conditions, we observe a 16.46% increase in current density distribution in converging design (partial humid condition) compared to the lowest current density obtained in diverging design (max humid condition) at 0.4 V. Further, we observed that the current density distribution in the converging design improved by 3.68% and 6.19% compared to the straight (conventional) and diverging design, respectively, under max humid condition at 0.4 V. Similarly, under the partial humid condition, the current density improved in the converging design by 3.46% and 4.98% compared to conventional and diverging designs respectively at 0.4 V. Using a comprehensive numerical analysis of reactant flow channel gradient designs, we show that the membrane hydration of operating cells is controlled through variation in transport characteristics. © 2023 Elsevier Ltd