Total energy flow and phenomenological equations

Example 7.3 Total energy flow and phenomenological equations For mixtures, the energy flow contains the conductive flow qc, and the contributions resulting from the interdiffusion q, of various substances and the Dufour effect q we therefore express the total energy flow relative to the mass-average velocity 

When we express the energy flow e with respect to fixed stationary coordinates by disregarding the Dufour effect, the viscous effect, and kinetic energy, we have 

Equation (7.136) is the usual starting point for simultaneous heat and mass transfer. 

Mass flow is associated with the mechanical driving forces and thermal driving force 

Ordinary diffusion depends on the partial Gibbs free energy and the concentration gradient. The pressure diffusion is considerable only for a high-pressure gradient, such as centrifuge separation. The forced diffusion is mainly important in electrolytes and the local electric field strength. Each ionic substance may be under the influence of 

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Example 7,5 Total energy flow and phenomenological equations... 

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