Learn Transport Phenomena with Balance Equations and Numerical Solutions: A Review of Plawsky's Book
Transport Phenomena Fundamentals: A Comprehensive Guide
Transport phenomena are the processes that describe how matter, energy, and information move from one place to another. They are essential for understanding and designing many engineering systems, such as heat exchangers, reactors, separators, membranes, microfluidics, and biomedical devices. In this article, we will introduce the basic concepts and principles of transport phenomena, the main topics and methods of study, and some useful resources for further learning.
transport phenomena fundamentals plawsky pdf 31
What are transport phenomena?
Transport phenomena can be defined as the study of the rates of transfer of mass, energy, momentum, and charge in physical and chemical systems. They are often classified into three types:
Heat transfer: the movement of thermal energy due to a temperature difference.
Mass transfer: the movement of chemical species due to a concentration difference.
Momentum transfer: the movement of fluid particles due to a pressure or velocity difference.
Charge transfer is a special case of mass transfer that involves electrically charged particles or ions. Transport phenomena can occur in different phases (solid, liquid, gas) or across phase boundaries (solid-liquid, liquid-gas, etc.). They can also be influenced by external forces (gravity, electric field, magnetic field) or interactions (chemical reactions, phase changes).
Some examples of transport phenomena are:
Conduction: heat transfer through a solid or a stationary fluid by molecular collisions.
Convection: heat or mass transfer by the bulk motion of a fluid.
Radiation: heat transfer by electromagnetic waves.
Diffusion: mass transfer by random molecular motion.
Osmosis: mass transfer across a semipermeable membrane due to a solvent concentration difference.
Viscosity: momentum transfer by internal friction in a fluid.
Laminar flow: fluid flow with smooth and orderly streamlines.
Turbulent flow: fluid flow with chaotic and irregular fluctuations.
Transport phenomena are important for many engineering applications, such as:
Thermal engineering: design and optimization of heat engines, refrigerators, heat pumps, boilers, furnaces, etc.
Chemical engineering: design and optimization of reactors, separators, distillation columns, absorption towers, etc.
Bioengineering: design and optimization of artificial organs, drug delivery systems, tissue engineering scaffolds, etc.
Nanotechnology: design and optimization of nanoscale devices and materials with enhanced thermal, electrical, optical, or mechanical properties.
How to study transport phenomena?
The study of transport phenomena requires a combination of mathematical modeling, physical reasoning, and experimental validation. A common approach is to use the balance equation method, which consists of four steps:
Modeling: identify the system of interest and define a control volume (a fixed or moving region in space) that encloses it.
Differential equations: derive the governing differential equations that describe how the transported quantity (mass, energy, momentum, charge) changes with time and space within the control volume.
Boundary conditions: specify the values or relations of the transported quantity at the boundaries of the control volume or at any internal surfaces.
Solution: solve the differential equations with the boundary conditions to obtain the distribution of the transported quantity in time and space.
The governing differential equations are usually based on conservation laws (mass conservation, energy conservation, momentum conservation) or constitutive relations (Fourier's law for heat conduction, Fick's law for diffusion, Newton's law for viscosity). They can be ordinary differential equations (ODEs) if they involve only one independent variable (usually time) or partial differential equations (PDEs) if they involve more than one independent variable (usually time and space).