Chemical Engineering @ChemengFiles.Com

All Chemical Engineer knows what is the transfer of momentum (momentum), heat and matter. The theory shows that there are analogies, physical and mathematical modeling, among these three mechanisms of transfer is known as transport phenomena. What is not well known is that these are not the only processes of displacement in time and space of a particular physical entity.

The flow of electrical current either through a conductor or in a electrolytic medium is itself a phenomenon of transport. Can also be called as a phenomenon of electrical charge transfer, is closely related to heat conduction in solids. Mathematically, Ohm's law of electric current driving (as differential) and the Fourier law of heat conduction are identical and represent a typical example of what is "Flux", the mathematical differential equation that combines speed transfer of the physical entity transported directly proportional to a force that motivates the movement, expressed as a gradient and a physical property inherent to conducting medium that facilitates (or inhibits) the displacement.

So then, the analogy between electrical and thermal conduction are both Ohm's Law and the Law of respective Fourier form: physical entity being carried, and Thermal Power Electric charge, force that motivates the movement, electrical potential difference ( voltage) and temperature gradient and thermal and electrical conductance. Note that in typical courses in physics, electrical conduit most commonly used the term "resistance" of a driver (in Ohms) in place of conductance. However we must remember that the other one is reciprocal. Similarly, from a physical point of view, it is well known empirically that good electrical conductors such as metals, are also good thermal conductors.

On the other hand, the transfer of electric charge and mass transfer are closely related in electrochemical systems. Much like in which the chemical reaction rate can be conditioned by the time it takes to reach the reactants to the surface of a catalyst through the mechanism of diffusion in an electrolytic medium, the reaction rate may be limited by the time it takes to reach the electrolyte to the electrode surface, this through a mechanism known as: migration. In fact, in an electrochemical system is normal to have both the diffusion and migration as combined mechanisms that constrain the speed of chemical reaction.

In hydraulics, for the flow of low viscosity, the flow can be determined from the pressure gradient and conductivity properties determined by the type of channel through which the flow exists. Known as Pouseuille Act, the analogy with electrical conduction and Ohm's law is so obvious that it is common to solve problems of piping systems like electrical circuits.

Considerably less known are the transport phenomena thermodynamic entities like entropy or free energy, since these variables are usually studied in steady state and not during the transfer process, or mechanics, the momentum transfer angle.

In conclusion, a unifying theory of transport phenomena, in addition to covering the classic study of transfer processes of momentum, heat and mass should include the processes of electrical charge transfer of angular momentum, entropy and Gibbs free energy, and Pouseuille Act as a special case of mass transfer at the macroscopic level driven by a hydraulic pressure gradient.