Implementation of a phenomenological evaporation model into a porous network simulation for water management in low temperature fuel cells

Fritz, David

doi:10.37099/mtu.dc.etds/360

Cited by 6 publications

(5 citation statements)

References 117 publications

(175 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The non-dimensional volume of evaporated water, V * ev , is defined as the ratio between the evaporated volume of water and the empty volume of the PTL. Figure [4] show the non-dimensional evaporated volume of water along the time for both models. From this figure, the kinetic model predict approximately 10 times more volume of water evaporation.…”

Section: Resultsmentioning

confidence: 99%

“…(ṁ ev ∆h ev ) ij [4] where the term ( ṁev ∆h ev ) ij is the rate of energy required to evaporate a liquid mass ṁev and ∆h ev is the enthalpy of formation. The term (vρc p ) ij is the total heat capacity at each node and depends not only on the heat capacity of the carbon fiber but also on the amount of water and air on the pores surrounding the node 'i'.…”

Section: Heat Liquid Water and Vapor Transport Modelsmentioning

confidence: 99%

“…Kinetic models are dependent upon the material and the location of water within the material and may take into account the effect of disjoining pressure, meniscus curvature, and non-equilibrium interface temperature (3). There is a significant divergence between the two phase change models as the number of pores increases (4).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diffusive - Kinetic Evaporation Models for Fuel Cells

2013

View full text Add to dashboard Cite

Modeling evaporation within a fuel cell porous transport layer (PTL) is a complex, conjugate phenomenon that is highly dependent upon the local morphology, wetting, and operating conditions. Two very distinct evaporation models, one diffusive and one kinetic have been used to study evaporation in fuel cell porous media. Both evaporation models are implemented into a pore network model of a PTL. Simulation using both models are compared under the same morphological, wetting, and operation condition. The mass of evaporated water and liquid water distribution inside the PTL compared for the two models.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Heat Liquid Water and Vapor Transport Modelsmentioning

confidence: 99%

See 1 more Smart Citation

Diffusive - Kinetic Evaporation Models for Fuel Cells

2013

View full text Add to dashboard Cite

show abstract

“…The net effect due to the interplay of anisotropies in local stress and heat transfer is a non-uniform evaporation flux that generally has a peak in the transition film (Bellur et al, 2020). For non-polar, wetting liquids, 60%-90% of the evaporation occurs in the transition film region close to the wall (Derjaguin et al, 1965;Potash and Wayner, 1972;Holm and Goplen, 1979;DasGupta et al, 1994;Wee et al, 2006;Plawsky et al, 2008;Fritz, 2012). The non-uniform evaporation results in a non-uniform temperature distribution making interfacial temperature, T i , a spatially varying quantity.…”

Section: Non-uniform Phase Change At Curved Interfacesmentioning

confidence: 99%

An investigation of phase change induced Marangoni-dominated flow patterns using the Constrained Vapor Bubble data from ISS experiments

Chakrabarti,

Yasin,

Bellur

et al. 2023

Front. Space Technol.

View full text Add to dashboard Cite

Kinetic models of liquid-vapor phase change often implicitly assume that the interface is in equilibrium. This equilibrium assumption can be justified for large flat interfaces far from the source of thermal energy, but it breaks down when the liquid surface is near a solid wall, or there is significant interface curvature. The Constrained Vapor Bubble (CVB) experiments conducted on the International Space Station (ISS) provide a unique opportunity to probe this common assumption and also provide unique data and insight into phase change-driven flow physics. The CVB experiment consists of a quartz cuvette partially filled with pentane such that a vapor bubble is formed at the center. The setup is heated and cooled at opposite ends, resulting in simultaneous evaporation and condensation. CVB data from the NASA Physical Science Informatics (PSI) database was used to reconstruct the entire 3D interface shape using interferometric image analysis and obtain an estimate of the net heat input to the bubble. The reconstructed interface shape is used to develop a liquid-only CFD model embedded with a custom-built “active surface” method that sets a variable interfacial temperature/phase change flux boundary condition. Phase change flux varies in both the axial and transverse directions, leading to a small (∼1 K) but discernible temperature variation along the liquid-vapor interface. The positive phase change flux near the heater end (denoting evaporation) gradually reduces and becomes negative near the cooler end (denoting condensation), resulting in an axial bulk flow of liquid from the cold to the hot end. There is also a higher flux in the thin film as opposed to the thick film, resulting in a transverse bulk flow. However, the interfacial temperature gradients along both axial and transverse directions induce a separate thermocapillary flow in a direction opposite to the bulk flows, leading to complex “wavy” flows with recirculation. A qualitative analysis of the flow pattern is presented in this paper and correlated with optical signatures from experimental images.

show abstract

“…Figure 1 is a preliminary comparison between the kinetic and diffusive evaporation models with the same surface area, but varying numbers of pores are used to attain the surface area. There is a significant divergence between the two phase change models as the number of pores increases [4].…”

mentioning

confidence: 98%