wheredis some characteristic length, like apipe diameteror a film thickness, andDis the samediffusion coefficientwhich we talked about earlier. The mass transfer coefficient is most frequently correlated as a function of velocity, which often appears in aReynolds numberRe (36)Re=dυν wherevis th...
The force unit in SI is the newton (N) and by using consistent units becomes the force applied to unit mass (kg) to impart unit acceleration (m s−2) to the mass (as distinct from gravitational acceleration, which equals 9.806 65 m s−2). Thus it can be more readily understood ...
kinematic viscosity, diffusion coefficient m2 × s-1 dynamic viscosity N× s × m-2 density of electric charge C× m-3 electric current density j A× m-2 electrical conductivity S× m-1 molar conductivity S× m2 × mol-1 dielectric constant e F× m-1 magnetic permeability µ H× m...
The extendedZwerger method of determining thechemical diffusion coefficient, for lattice gasconventional diffusion in equilibrium andsuperdiffusion in stationary state, isverified by Monte Carlo simulation of thecentre-of-mass propogation. It has been found that the chemical diffusion coefficient for super...
where \({j}_{L}\) is the average current density on the electrode at the steady-state, \(\beta\) a constant related to the measurement units, \(n\) number of electrons involved in the reaction, \(F\) the Faraday constant, \(D\) the diffusion coefficient of the limiting species, ...
the process takes place in a space with a nonuniform concentration or partial pressure field of the component. In the case of thermal diffusion, mass transfer also results from a temperature difference. Mass transfer between a moving medium and an interface with another medium is called mass emis...
5. Gas diffusion electrodes (GDEs), which allow the direct utilization of gaseous feedstocks and greatly shorten the gas delivery length, are widely recognized as the most suitable platform for 2e−ORR6,7,8,9,10. Particularly for those GDEs with breathing-mimicking designs, the capability to ...
{D}\right)\)permits quantifying the energy budget into consumable units and can produce thermal optima33(e.g., Fig.1B) even in cases where a monotonic exponential rise in oxygen supply with temperature exists30. An absolute form of Φ could thus prove a powerful new tool to further ...
Note that ρ has units of mass per present volume, while ρR has units of mass per reference volume (see Table 9.1). Both ρ and ρR are bounded, continuous functions of space and time. Table 9.1. Units for Thermal, Electrical, Magnetic, and Mechanical Quantities TypeQuantityRepresentation...
The mass transfer proceeded in the form of diffusion and the process was transient. For penetration model, the mass transfer coefficient is calculated by Eq. (24). The pictorial process of the penetration model is given in Fig. 7. Sign in to download hi-res image Fig. 7. Pictorial ...