What is a stagnant film?

An assumption used in mass transfer calculations in which there is an assumed stationary film of gas or liquid surrounding an object such as a particle through which a component diffuses…. …

What is stagnant diffusion?

Diffusion occurs when a concentration gradient exists in the liquid phase: it is the main transport mechanism for stagnant liquids in pores. Dissolved substances inside a porous block material are diffused to the surface of the block and then released in the environment.

What is stagnant fluid?

In fluid dynamics, a stagnation point is a point in a flow field where the local velocity of the fluid is zero.

What do you mean by equimolar counter diffusion?

Equimolar counterdiffusion is an instance of molecular diffusion in a binary mixture, and occurs when equal numbers of molecules of the two substances are moving in opposite directions.

What is stagnant layer?

When an aqueous solution moves tangentially to a charged surface, as in electrophoresis and all other electrokinetic phenomena, a thin water layer remains immobilized: the stagnant layer. The plane separating the stagnant layer and the mobile part of the fluid is the slip plane.

What is a stagnant fluid?

Why is CP 1 at stagnation?

is pressure at points remote from the body (free-stream static pressure) is dynamic pressure at points remote from the body. Stagnation pressure minus static pressure is equal to dynamic pressure; therefore the pressure coefficient Cp at stagnation points is 1.

What is stagnant area?

1. Existence of the stagnant zone. The so-called stagnant zone refers to the section in a reactor where fluid flows very slowly or does not flow at all. Hence, the stagnant zone is also called the dead zone.

What is molar flux?

The molar flux is the number of moles per unit time per unit area, generally: So the molar flux of component i is (number of moles per unit time per unit area): and the barycentric molar flux of component i is.

What is steady state diffusion?

Steady state diffusion is characterized by a constant concentration gradient. It is obtained by imposing a limited solubility on the compound of interest and offers the possibility of an appreciable reduction of the emission(‐rate) from a waste body.

What is Noyes Whitney equation?

2.3. The dissolution rate of a solid in solvent is written by Noyes–Whitney equation, as follows,(1) dC dt = DS w Vh ( C s − C ) , where C and Cs represent the concentration of the dissolved substance at a given time t and the solubility concentration of the substance, respectively.