Optimum design conditions, entropy

The optimal Reynolds number defines the operating conditions at which the cylindrical system performs a required heat and mass transport, and generates the minimum entropy. These expressions offer a thermodynamically optimum design. Some expressions for the entropy production in a multicomponent fluid take into account the coupling effects between heat and mass transfers. The resulting diffusion fluxes obey generalized Stefan-Maxwell relations including the effects of ordinary, forced, pressure, and thermal diffusion. 

Thus, by consideration of the rate of entropy production in the main exchanger, the optimum pressure drop and temperature difference across this exchanger may be estimated without the necessity for a complete system design at each combination of conditions. 

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