A comparative analysis of a novel flow field pattern with different channel size configurations

Hazar, Hanbey; Yılmaz, Mustafa; Sevinc, Huseyin

doi:10.1016/j.fuel.2022.123867

Cited by 9 publications

(2 citation statements)

References 62 publications

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“…For models I and III, the maximum downstream pressure was developed at the end of one complete cycle due to fully developed flow [ 45 , 46 ]. In microchannels [ 47 , 48 ], the flow restriction parameter R depended on the channel length, which caused maximum pressure to be generated at the inlet region for the case of the non-Newtonian viscosity formulation with sinusoidal and physiological flows in serpentine models S1 and S2. For the non-Newtonian formulation with physiological flow of serpentine model 2, minimal variations in the magnitude of the flow parameters were found due to insignificant variation of the pressure gradient at different flow fluxes.…”

Section: Discussionmentioning

confidence: 99%

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Deshmukh,

Mitra,

Bit

2023

Micromachines

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The viscosity of fluid plays a major role in the flow dynamics of microchannels. Viscous drag and shear forces are the primary tractions for microfluidic fluid flow. Capillary blood vessels with a few microns diameter are impacted by the rheology of blood flowing through their conduits. Hence, regenerated capillaries should be able to withstand such impacts. Consequently, there is a need to understand the flow physics of culture media through the lumen of the substrate as it is one of the vital promoting factors for vasculogenesis under optimal shear conditions at the endothelial lining of the regenerated vessel. Simultaneously, considering the diffusive role of capillaries for ion exchange with the surrounding tissue, capillaries have been found to reorient themselves in serpentine form for modulating the flow conditions while developing sustainable shear stress. In the current study, S-shaped (S1) and delta-shaped (S2) serpentine models of capillaries were considered to evaluate the shear stress distribution and the oscillatory shear index (OSI) and relative residual time (RRT) of the derivatives throughout the channel (due to the phenomena of near-wall stress fluctuation), along with the influence of culture media rheology on wall stress parameters. The non-Newtonian power-law formulation was implemented for defining rheological viscosity of the culture media. The flow actuation of the media was considered to be sinusoidal and physiological, realizing the pulsatile blood flow behavior in the circulatory network. A distinct difference in shear stress distributions was observed in both the serpentine models. The S1 model showed higher change in shear stress in comparison to the S2 model. Furthermore, the non-Newtonian viscosity formulation was found to produce more sustainable shear stress near the serpentine walls compared to the Newtonian formulation fluid, emphasizing the influence of rheology on stress generation. Further, cell viability improved in the bending regions of serpentine channels compared to the long run section of the same channel.

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Section: Discussionmentioning

confidence: 99%

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Deshmukh,

Mitra,

Bit

2023

Micromachines

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“…Though the relation between the power generation characteristics and O2 profile or flow filed distribution was discussed, that between the power generation characteristics and the temperature distribution was not studied. Regarding the general PEMFC operated below 353 K, the several flow fields of separator such as a modified parallel flow field [16], a blocked flow field [17], a modified serpentine wave flow filed [18], a straight channel with baffled obstacles [19] and an ultrathin steel separator whose thickness was 0.1 mm [20] were investigated. Since the weight ratio of separator to that of total cell is approximately 80 % [21], it is important to optimize the design of separator.…”

Section: Introductionmentioning

confidence: 99%

Impact of Separator Thickness on Relationship between Temperature Distribution and Mass & Current Density Distribution in Single Cell of HT-PEFC

Nishimura,

Mishima,

Ito

et al. 2023

Preprint

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For the polymer electrolyte fuel cell (PEFC), the separator thickness plays an important role to determine the weight, the volume and the costs of the PEFC. In addition, thermal management, i.e. temperature distribution is also important for the PEFC system to obtain higher performance. However, there were few reports investigating the relationship between the temperature distribution and the power generation performance such as current density distribution of PEFC operated at higher temperature (HT-PEFC). The aim of this study is to clarify the impact of separator thickness on the relationship between the temperature distribution and the current density distribution of HT-PEFC. This study has also investigated the impact of separator thickness on the relationship between the temperature distribution and the gases such as H2, O2 and the current density distribution of HT-PEFC numerically using CFD software COMSOL Multiphysics. The separator thicknesses of 2.0 mm, 1.5 mm and 1.0 mm were studied. In the study, the operation temperature and the relative humidity (RH) of supply gas were also changed. As a result, it was revealed that the optimum separator thickness was 2.0 mm to obtain higher power generation of HT-PEFC. Since the heat capacity in the case of the separator thickness of 2.0 mm was the largest among the separators investigated in this study, the dehydration of PEM and catalyst layer was smaller compared with the thinner separator thicknesses. It was also revealed that the impacts of separator thickness on distribution of gases, e.g. O2, H2O, and current density distribution became larger under higher temperature and lower RH conditions. This study also concluded that the tendency of temperature distribution matched those of O2, H2O and current density distributions.

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Investigation of the effects of intermediate reservoirs and intermediate feedings applications on the performance of proton exchange membrane fuel cells

Celik

Karagöz

2023

Fuel

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A comparative analysis of a novel flow field pattern with different channel size configurations

Cited by 9 publications

References 62 publications

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Impact of Separator Thickness on Relationship between Temperature Distribution and Mass & Current Density Distribution in Single Cell of HT-PEFC

Investigation of the effects of intermediate reservoirs and intermediate feedings applications on the performance of proton exchange membrane fuel cells

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A comparative analysis of a novel flow field pattern with different channel size configurations

Cited by 9 publications

References 62 publications

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Influence of Non-Newtonian Viscosity on Flow Structures and Wall Deformation in Compliant Serpentine Microchannels: A Numerical Study

Impact of Separator Thickness on Relationship between Temperature Distribution and Mass &amp; Current Density Distribution in Single Cell of HT-PEFC

Investigation of the effects of intermediate reservoirs and intermediate feedings applications on the performance of proton exchange membrane fuel cells

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Product

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About

Impact of Separator Thickness on Relationship between Temperature Distribution and Mass & Current Density Distribution in Single Cell of HT-PEFC