What is Transport phenomena: Definition and 30 Discussions
In engineering, physics and chemistry, the study of transport phenomena concerns the exchange of mass, energy, charge, momentum and angular momentum between observed and studied systems. While it draws from fields as diverse as continuum mechanics and thermodynamics, it places a heavy emphasis on the commonalities between the topics covered. Mass, momentum, and heat transport all share a very similar mathematical framework, and the parallels between them are exploited in the study of transport phenomena to draw deep mathematical connections that often provide very useful tools in the analysis of one field that are directly derived from the others.
The fundamental analysis in all three subfields of mass, heat, and momentum transfer are often grounded in the simple principle that the total sum of the quantities being studied must be conserved by the system and its environment. Thus, the different phenomena that lead to transport are each considered individually with the knowledge that the sum of their contributions must equal zero. This principle is useful for calculating many relevant quantities. For example, in fluid mechanics, a common use of transport analysis is to determine the velocity profile of a fluid flowing through a rigid volume.
Transport phenomena are ubiquitous throughout the engineering disciplines. Some of the most common examples of transport analysis in engineering are seen in the fields of process, chemical, biological, and mechanical engineering, but the subject is a fundamental component of the curriculum in all disciplines involved in any way with fluid mechanics, heat transfer, and mass transfer. It is now considered to be a part of the engineering discipline as much as thermodynamics, mechanics, and electromagnetism.
Transport phenomena encompass all agents of physical change in the universe. Moreover, they are considered to be fundamental building blocks which developed the universe, and which is responsible for the success of all life on earth. However, the scope here is limited to the relationship of transport phenomena to artificial engineered systems.
I have a discussion with a colleague of mine.
We have a thin cuboid sample whose two dimensions are similar to each other and are both much bigger than the sample thickness. I'm doing an experiment in which the diffusion of some species is induced and its diffusion profile is measured in one of...
My attempt:
Species fluid and solid phase balances for a tubular reactor in which there is a homogeneous first order reaction and a heterogeneous reaction on the external surface of non-porous catalyst coated along the reactor wall.
Mole balance equation for the fluid phase
The heterogeneous...
Consider a fluid flow with density ##\rho=\rho(t,x)## and velocity vector ##v=v(t,x)##. Assume it satisfies the continuity equation
$$
\partial_t \rho + \nabla \cdot (\rho v) = 0.
$$
We now that, by Reynolds Transport Theorem (RTT), this implies that the total mass is conserved
$$...
Stefan-Maxwell and Onsanger equations are equations which can be used to calculate mole flux of the component due to different types of gradients. It is assumed that driving forces of mass transfer are in equilibrium with drag forces due to interaction of different types of components...
I am able to find and understand T from kinetic theory, but I do not understand how to use pressure gradient per unit of area and per unit pressure gradient.
In this topic >> https://www.physicsforums.com/threads/stress-tensor-for-non-Newtonian-fluid.860240/
Mr. Chestermiller replies that "For a purely viscous non-Newtonian fluid (not viscoelastic), you use exactly the same form of equation as for a Newtonian fluid (see Bird, Stewart, and...
What's really the difference between pressure and normal stress? Also I know pressure acts normal to a surface from the outside
Do normal stress acts from inside?
I'm reading bird transport phenomena and this is confusing
in the book " transport phenomena" (Bird) when obtaining the famous equation of hagen poiseuille
Bird defines a variable that involves the pressure, but when doing an exercise a term magically disappeared, someone could explain to me what happened
why we took into account the pressure in this...
Derivation of the Onsager symmetry in many textbooks and papers is as follows: First, assume that the correlation function of two state variables,##a_i## and ##a_j## satifsies for sufficiently small time interval ##t## that
$$\langle a_i(t) a_j(0) \rangle = \langle a_i(-t) a_j(0) \rangle =...
In my heat transfer course, I always had to do analysis of long-wavelength radiation between surfaces first, and find the heat radiated from one of the surface. Then, solar radiation is added to the problem, and suddenly it was said that solar radiation=heat radiated from this surface! Does...
Hello and thanks for looking at this question.
I have a semi-conducting sample which has been run on a PPMS system - measuring it's resistivity as a function of temperature.
I switched to AC transport mode in order to measure the resistivity again while applying frequencies between 1Hz -...
Hi,
Our lecturer explained us the Reynold Transport theorem, its derivation , but I don't get where the - sign in control surface 1 comes from? He said that the Area goes in opposite direction compared with this system.
I can't visualise this on our picture.
Can you please help me understand...
I have a question regarding writing a shell balance for a cylindrical system with transport in one direction (in any area of transport phenomena). When we set up the conservation equation(say steady state), we multiply the flux and the area at the surfaces of our control volume and plug them...
Homework Statement
Homework Equations
0=viscous+gravitational+pressure
I saw in the solutions that pressure=0 in this case, but why?
I also knew that : accumulation= flow in - flow out+generation, why not use this one?
The Attempt at a Solution
(their solution)
We are interested in...
I'd like to purchase one of these books for self-study. The BSLK Introductory Transport Phenomena claims:
"Devoting more space to mathematical derivations and providing fuller explanations of mathematical developments—including a section of the appendix devoted to mathematical topics—allows...
Homework Statement
Hello, I am struggling with this heat transfer and fluid flow problem.I would really appreciate if someone could have a look over what I have done on it.
I am not sure if what I have done is correct ,I would really appreciate if you could tell me if it is correct or wrong.And...
Homework Statement
I would really appreciate if someone could help me out with this exercise in fluid flow/heat transfer ,because I really struggling with it.Below I am attaching photo of problem+table with values. Thank you in advance !Homework Equations
Question link:[/B]...
Hi, PF!
Recently, while reading chapter 6 of Incropera's Fundamentals of Heat and Mass Transfer I got into a confusion regarding the velocity boundary layer. The book first states that, as the flow becomes more turbulent, the boundary layer gets thicker, as indicated by both figures attached at...
I want to model the diffusion-controlled combustion of a small carbon particle. The system I want to model is similar to this one
However, I'm not going to use the stagnant gas film model as shown in the figure, since I lack data for the film thickness, and I want to evaluate the problem...
Hi, PF! I recently solved a problem from BSL which asked to analyze the following system used for determining the diffusivity of a binary mixture of gases.
The left portion of the system, from the left bulb up to the stopcock at the middle of the tube, is filled with gas A. The right portion...
Homework Statement
Problem 18B.13 from Transport Phenomena, BSL.
Tarnishing of metal surfaces. In the oxidation of most metals the volume of oxide produced is greater than that of the metal consumed. This oxide thus tends to form a compact film, effectively insulating the oxygen and metal from...
Hi, PF! In the study of mass transfer involving chemical reactions, I have seen the use of two different non-dimensional parameters which apparently quantify the same ratio. These are the second Damköhler number and the Thiele modulus, which are defined as
\textrm{Da}^{\textrm{II}} =...
Hello, PF! I have some doubts about setting up shell balances in a cylindrical geometry. Consider a fluid flowing down a vertical pipe. In order to perform the momentum balance, we take a cylindrical (annular) shell of length L and width Δr. The analysis of such system can be found in chapter 2...
Greetings, PF! I have some questions regarding the problem I attached below. It is some sort of Couette flow variation. It's not homework, I'm just learning the basics of TP on my own. I fully solved the problem with the Navier-Stokes and continuity equations, using some assumptions in order to...
1. Homework Statement
Calculate the torque on the dam about the origin (Picture attached) due to the pressure force of the fluid.
Homework Equations
Pressure force is correct (dF)
The Attempt at a Solution [/B]
I have solve it; however, I am not sure if I calculated over the origin asked...
I am a graduate student in physics.
Can someone recommend a book that explores transport phenomena or diffusion from a physical sciences (instead of engineering) point of view? I would like that because I'm not dealing with industrial equipment and don't want to spend chapters wading through...
I am facing a problem on transport phenomena. Can anyone help me to solve this problem. I would really appreciate it. Its little urgent. I know that i have to use shell mass balance to start the problem but how to proceed further is what making me confused.
In a beaker, a solid sphere of...
Homework Statement
Use a shell balance method to derive the equation governing the two dimensional temperature distribution,u, in a circular disk in polar coordinate system(r,theta). allow for the possibility of differing thermal conductivities in the r and theta directions.
Homework...