CHE3123 Chap15BW - CHE 3123 Momentum, Heat and Mass...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
CHE 3123 Momentum, Heat and Mass Transfer II “Review Momentum Transport (as in 3113) Newton’s τ μ dv velocity viscosity law dy (eq.7-4) viscosity direction stress of momentum (force/area)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
y fluid moving v along a plate x Fluids that obey this law (water etc. ) are called “Newtonian”
Background image of page 2
Besides looking at τ as a stress, or force per unit area, we can also look at τ as, momentum transport per time per area. That is momentum is being transported towards the plate by “fast” particles of fluid rubbing against relatively slow particles Look at units of τ τ force N kg-m area m 2 s 2 .m 2 kg m 1 1 s m 2 s
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
(mass) (velocity) momentum area . time area . time HEAT TRANSPORT You will find heat transport easier to understand. Momentum transport involves the transport of a vector quantity, momentum. But heat transport involves only a scalar quantity, thermal energy.
Background image of page 4
The relation in heat transfer which is analogous to Newton’s law of viscosity is Fourier’s law heat/time temperature Fourier q x k dT Law A dx area to thermal direction direction of heat conductivity of heat flow transport
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
A more general form of this, in vectors notation, is q k T A Observe that q x a flux A energy,momentum,mass stuff (area) (time)
Background image of page 6
As this mention of “stuff” suggests, let us write down the third important equation for this course conc. Fick’s first J A,z D A,B dc A law dz (eq 24-15) molar flux diffusivity in z direction (of component A)
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Note that the gradients or driving forces for the three transfer phenomena are dv a velocity gradient dz dT a temperature gradient dz dc A a concentration gradient dz
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/07/2009 for the course CBME Kinetics & taught by Professor Lobban during the Spring '09 term at The University of Oklahoma.

Page1 / 34

CHE3123 Chap15BW - CHE 3123 Momentum, Heat and Mass...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online