Self-flux condition

EFFECT OF REDUCTION CONDITIONS ON PRE-REDUCTION BEHAVIORS OF SELF-FLUXED PELLETS IN COREX PROCESS... 

By inspection, the flux is directly proportional to the solubility to the first power and directly proportional to the diffusion coefficient to the two-thirds power. If, for example, the proposed study involves mass transport measurements for series of compounds in which the solubility and diffusion coefficient change incrementally, then the flux is expected to follow this relationship when the viscosity and stirring rate are held constant. This model allows the investigator to simulate the flux under a variety of conditions, which may be useful in planning experiments or in estimating the impact of complexation, self-association, and other physicochemical phenomena on mass transport. 

The hottest fires may be associated with those cases where the fire is big enough to give flames to fill at least half the structure volume, cases where it is stoichiometric or just under ventilated, and cases where the hot gas layer is 10 ft (3 m) or more deep. Heavier fuels would be less likely to give the hottest fires, asthey may not receive enough heat feedback to vaporize the liquid and therefore they may be self limiting in terms of the burn rate. Where these conditions may be encountered, heat fluxes of 1320-1584 BTU/ft (250 to 300 kW/m ) may be experienced. In certain circumstances, (which are not yet fully understood) highly efficient combustion can occur with fluxes of 1848-2112 BTU/ft (350-400 kW/m2) and temperatures of 2,500°F (1,400°C). 

The above self-similar velocity profiles exists only for a Re number smaller than a critical value (e.g. 4.6 for a circular pipe). The self-similar velocity profiles must be found from the solution of the Navier-Stokes equations. Then they have to be substituted in Eq. (25) which must be solved to compute the local Nusselt number Nu z). The asymptotic Nusselt number 7Vm is for a pipe flow and constant temperature boundary condition is given by Kinney (1968) as a function of Rew and Prandtl (Pr) numbers. The complete Nu(z) curve for the pipe and slit geometries and constant temperature or constant flux boundary conditions were given by Raithby (1971). This author gave /Vm is as a function of Rew and fluid thermal Peclet (PeT) number. Both authors solved Eq. (25) via an eigenfunction expansion. 

Single-component diffusion under equilibrium conditions can be monitored either by labeling some of the molecules or by following their trajectories. Considering the diffusion flux of the labeled molecules, again a proportionality relation of the type of eq 2 may be established. The factor of proportionality is called the coefficient of self-diffusion (or tracer diffusion). In a completely equivalent way [2], the self-diffusion coefficient may be determined on the basis of Einstein s relation... 

Mass transfer in catalysis proceeds under non-equilibrium conditions with at least two molecular species (the reactant and product molecules) involved [4, 5], Under steady state conditions, the flux of the product molecules out of the catalyst particle is stoi-chiometrically equivalent (but in the opposite direction) to the flux of the entering reactant species. The process of diffusion of two different molecular species with concentration gradients opposed to each other is called counter diffusion, and if the stoichiometry is 1 1 we have equimolar counter diffusion. The situation is then similar to that considered in the case of self-or tracer diffusion, the only difference being that now two different molecular species are involved. Tracer diffusion may be considered, therefore, as equimolar counter diffusion of two identical species. 

Wagner enhancement factor — describes usually the relationships between the classical - diffusion coefficient (- self-diffusion coefficient) of charged species i and the ambipolar - diffusion coefficient. The latter quantity is the proportionality coefficient between the - concentration gradient and the - steady-state flux of these species under zero-current conditions, when the - charge transfer is compensated by the fluxes of other species (- electrons or other sort(s) of -> ions). The enhancement factors show an increasing diffusion rate with respect to that expected from a mechanistic use of -> Ficks laws, due to an internal -> electrical field accelerating transfer of less mobile species [i, ii]. 

Conditions of qsoiar > t ph0t can be shown to place specific restrictions on the photoabsorber. When Hi20 < Etneut, heat must flow to compensate for the self cooling which occurs at the electrolysis rate. That is, for an enthalpy balanced system any additional required heat must flow in a flux equivalent to iieai = imo, and at an average power dieat, such that ... 

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