These results indicate the importance of multicomponent transport for some operating conditions.However, for most of the operating range, binary mixture approximations are valid and Fick’s law of diffusion can be applied with small errors.
These results indicate the importance of multicomponent transport for some operating conditions.However, for most of the operating range, binary mixture approximations are valid and Fick’s law of diffusion can be applied with small errors.The results are shown to be in qualitative agreement with published experimental data, thereby providing a preliminary validation of the modeling approach.Tags: Essay On Safety At Construction SiteIeee Research Papers On Web ServicesGood Managers Are Born Not Made EssayEssay To Sonnet 3Essayer De PreuveThesis Statement About Solar EnergyAp Essay Questions Beowulf
Furthermore, it requires extensive parameter identification to fit the modeling results to experimental data.
Nevertheless, it remains one of the main models that is used in the control community. proposed a reduced model for nonlinear model predictive control applications, where they used representative elementary volumes (REVs) to reduce partial differential equations (PDEs) into ordinary differential equations (ODEs).
Order of magnitude analysis has been reported in the literature to show the time constants associated with various dynamics in the cell. presented such an analysis, where they found the time constants for gas diffusion in porous media and reaction kinetics to be on the order of a few milliseconds.
They also associated a time constant of 2 × 10 where they also found the dynamics associated with gas species diffusion to be very fast compared to other transients.
Nevertheless, significant computational reductions can be achieved with pseudo 2-D models, where the channel concentrations are found and used to serve as spatially varying boundary conditions for the through-the-membrane sandwich model.
This approach is specifically useful for straight-channel flow fields, where the usual corner effects in interdigitated and serpentine flow fields are not present.
Computational efficiency is achieved by leveraging the disparate time scales within the system dynamics, in addition to exploiting the large aspect ratio of the cell layers to create a spatio-temporal decoupling.
Taking advantage of such decoupling, the model yields a computationally efficient solution while providing detailed information about the state of water and temperature throughout the cell.
Within the context of this paper, a fuel cell model is considered to have high fidelity if it incorporates the following phenomena: i) 3-D effects including anisotropic material properties A more detailed explanation of these considerations follows.
In terms of dimensionality, 3-D models are of highest fidelity, because they are capable of capturing transport in both through-the-membrane and along-the-channel directions and also account for the channel-land effects in the third dimension.