Chapter 6

Question 1

Cf Definition and Equation

Answer 1

Local friction coefficient and τs/ρuinf^2/2

Question 2

Equation for shear stress

Answer 2

τs=µ*du/dy @y=0

Question 3

qs’’ defintion and formula

Answer 3

surface heat flux and -kfdT/dy @Y=0

Question 4

Newtons law of cooling

Answer 4

qs’‘=h(Ts-T∞)

Question 5

μ name and meaning

Answer 5

mu and dynamics viscosity

Question 6

Where is the velocity boundry layer located.

Answer 6

Underneath the free stream

Question 7

what is delta in terms of the free stream.

Answer 7

The y distance from the surface where the free stream is located

Question 8

kF

Answer 8

conductivity of fluid at surface ie no velocity still due to no slip condition

Question 9

surface heat flux formula

Answer 9

qs’’=-kf*dT/dy @y=0

Question 10

What is the driving force for conduction and convection

Answer 10

Temperature Difference

Question 11

Thermal Boundry Layer

Answer 11

Layer of the fluid flow were Temperature Gradient exists

Question 12

Analogy between shear stress and surface flux.

Answer 12

Both happen @y=0, and a coefficient time the derivative they have respect too

Question 13

Equation for heat flux due to convection

Answer 13

qs’‘=h*(Ts-Tinf)

Question 14

Equation for h

Answer 14

-KfdT/dy/(Ts-Tinf)

Question 15

Are the thicknesses of the thermal boundary layer and the velocity boundary layer the same

Answer 15

no

Question 16

How is heat transferred inside the boundary layer and outside the boundary layer?

Answer 16

The heat is transferred inside the boundary layer by conduction due to low velocity and by convection outside the boundary layer by convection.

Question 17

Driving force of mass transfer?

Answer 17

Delta C aka Difference in concentration

Question 18

NA’’ meaning and units aka

Answer 18

molar Flux kmol/m^2*s Ficks Law

Question 19

NA’’ formula

Answer 19

-DAB dCA/dy

Question 20

C

Answer 20

molar concentration

Question 21

D term and meaning

Answer 21

Binary Diffusion coefficient

Question 22

hm

Answer 22

convection mass transfer coefficient

Question 23

n’’ and units

Answer 23

mass flux kg/s*m^2

Question 24

h definition and equation

Answer 24

heat transfer coefficient h=-kfdT/dy/Ts-Tinf

Question 25

hm definition and equation

Answer 25

convection mass transfer coefficient -DAB dCA/dy/CAs-CAinf

Question 26

Reynolds number definition and equation

Answer 26

dimensionless parameer which defines were turbulent flow beigns. ρ*u(inf)*x/μ

Question 27

Mach number definition and equation

Answer 27

M= v

Question 28

Prandt Number

Answer 28

Ratio of momentum and thermal diffusivity-Pr=v/α The kinematic viscosity of a fluid in correlation with the thermal conductivity

Question 29

μ meaning and definition

Answer 29

dymanic viscocity -This represents the ratio between shear stress to shear strain.

Question 30

v

Answer 30

kinematic viscocity-This represents the ratio between dynamic viscosities to density. mu/rho

Question 31

On a isothermal flat plate as the distance of x increases what happens to the gradient? and why?

Answer 31

It must decrease. The gradient is classified as Dt/dy. As x increase the height of the free stream increase while Dt is constant so the numerator becomes larger hence the gradient becomes smaller.

Question 32

Nusselt Number equation and meaning

Answer 32

hL/kf, ratio of convection to conduction heat transfer

Question 33

ν

Answer 33

kinematic viscocity

Question 34

hm equation

Answer 34

(-Dab dCA/dy)/(Cas-Cainf)

Question 35

viscous sublayer meaning and mode of heat transfer

Answer 35

flow just above the plate were flow is nearly linear and dominated by diffusion turbulent region

Question 36

incompresable meaning

Answer 36

constant density

Question 37

Schmidt Number formula and meaning

Answer 37

v/DAB ratio of momentum and mass diffusivities

Question 38

Sherwood Number

Answer 38

hmL/DAB and ratio of convective mass transfer to the diffusive mass transfer

Question 39

Lewis Number Definition and formula.

Answer 39

Provides the measure of the convection mass transfer occurring at the surface. Ratio of thermal and mass diffusivities. α/Dab

Question 40

Two formulas for NA'' s

Answer 40

-DAB*dCa/dy @y=o | hm*(Ca,S-Ca,∞)

Question 41

formula for hm

Answer 41

(-DAB*dCa/dy)/(hm*(Ca,S-Ca,∞)