Description

The exchange of mass, energy, charge, momentum, and angular momentum between observable and researched systems is the subject of transport phenomena research in engineering, physics, and chemistry. While it draws on a variety of subjects, such as continuum mechanics and thermodynamics, it focuses heavily on the topics' commonalities.

Overview

The mathematical frameworks of mass, momentum, and heat transfer are all quite similar, and the similarities are used in the study of transport phenomena to draw deep mathematical linkages that frequently provide very valuable tools in the analysis of one subject that are directly derived from the others. The exchange of mass, energy, charge, momentum, and angular momentum between observable and researched systems is the subject of transport phenomena research in engineering, physics, and chemistry. While it draws on a variety of subjects, such as continuum mechanics and thermodynamics, it focuses heavily on the topics' commonalities.

The mathematical frameworks of mass, momentum, and heat transfer are all quite similar, and the similarities are used in the study of transport phenomena to draw deep mathematical linkages that frequently provide very valuable tools in the analysis of one subject that are directly derived from the others. Heat conduction (energy transmission), fluid flow (momentum transfer), molecular diffusion (mass transfer), radiation, and electric charge transfer in semiconductors are examples of transport processes.

The phenomena of transportation have a wide range of applications. The motion and interaction of electrons, holes, and phonons, for example, are studied in solid state physics as "transport phenomena." Another example is in biomedical engineering, where thermoregulation, perfusion, and microfluidics are all interesting transport phenomena. Transport phenomena are examined in reactor design, analysis of molecular or diffusive transport mechanisms and metallurgy in chemical engineering. The domains of process, chemical, biological, and mechanical engineering are some of the most prevalent instances of transport analysis in engineering, but the subject is a core component of the curriculum in all disciplines that deal with fluid mechanics, heat transfer and mass transfer in some form. It is today regarded as a branch of engineering, alongside thermodynamics, mechanics, and electromagnetic. All physical change agents in the cosmos are included in transport phenomena. Furthermore, they are thought to be fundamental building pieces that helped to create the universe and are responsible for all life on Earth's success. The focus of this paper is on the link between transportation phenomena and artificially engineered systems. In physics, transport phenomena are all statistically irreversible processes that arise from the random continuous motion of molecules, which are most commonly observed in fluids. Two fundamental principles underpin all aspects of transportation phenomena: conservation laws and constitutive equations. The conservation laws, which are written as continuity equations in the context of transport events, indicate how the quantity being researched must be conserved.

Constitutive Equations

The constitutive equations describe how the quantity responds to different stimuli via transport. The Navier-Stokes equations and Fourier's law of heat conduction, for example explain the response of heat flow to temperature gradients and the relationship between fluid flux and the forces applied to the fluid, respectively. These equations also show that transport phenomena and thermodynamics are inextricably linked, which explains why transport phenomena are irreversible. Almost all of these physical phenomena entail systems pursuing their lowest energy state in accordance with the minimal energy principle.

They tend to establish real thermodynamic equilibrium as they approach this condition, at which time there are no more driving forces in the system and transit ceases. Heat transfer is the system's endeavour to establish thermal equilibrium with its environment, much as mass and momentum transit move the system toward chemical and mechanical equilibrium. Heat conduction (energy transmission), fluid flow (momentum transfer), molecular diffusion (mass transfer), radiation, and electric charge transfer in semiconductors are examples of transport processes.

The phenomena of transportation have a wide range of applications. The motion and interaction of electrons, holes, and phonons, for example, are studied in solid state physics as "transport phenomena." Another example is in biomedical engineering, where thermoregulation, perfusion, and microfluidics are all interesting transport phenomena. Transport phenomena are examined in reactor design, analysis of molecular or diffusive transport mechanisms and metallurgy in chemical engineering. The existence of external sources can influence mass, energy, and momentum transport.

When the source of the odour is still present, it disappears more slowly (and may worsen). Whether or not a heat source is applied affects the pace of cooling of a solid that conducts heat. The resistance or drag imparted by the surrounding air is counteracted by the gravitational force exerted on a rain drop. Temperature variations cause heat to flow from warmer to colder areas of the system, while pressure differences cause matter to flow from high-pressure to low-pressure regions in fluid systems characterised in terms of temperature, matter density and pressure.

The fact that temperature differences at constant pressure can induce matter flow (as in convection) and pressure differences at constant temperature can cause heat flow is remarkable. Surprisingly, the density (matter) flow per unit of temperature difference and the heat flow per unit of pressure difference are similar. Lars Onsager used statistical mechanics to prove that this equality is required as a result of the time reversibility of microscopic dynamics. Understanding the release and spread of contaminants into the environment necessitates a study of transport processes.

Mass Transfer

Mass transfer is the net movement of mass from one location to another, which is commonly a stream, phase, fraction or component. Absorption, evaporation, drying, precipitation, membrane filtration and distillation are all examples of mass transfer processes. Different scientific areas use mass transfer for various processes and mechanisms. Physical processes involving diffusive and convective transport of chemical species inside physical systems are usually referred to as "diffusive and convective transport.” The evaporation of water from a pond to the atmosphere, the cleansing of blood in the kidneys and liver and the distillation of alcohol are all instances of mass transfer processes. Separation of chemical components in distillation columns, absorbers such as scrubbers or strippers and absorbers are all examples of mass transfer procedures in industrial processes.