Chapter 3 Flashcards
Diffusion
net transfer of energy by random molecular motion
Thermal Resistance for Conduction
L/KA
Thermal Resistance for Convection
1/hA
T infinity
Temperature of Bulk Fluid
q
Heat flow rate
h
Heat transfer coefficient convection
1/hA
Thermal Resistance convection
L/KA
Thermal Resistance conduction
Units for Rt
K/W
Units for Rt’’
m^2*K/W
hr meaning
Radiation heat Transfer Coefficient
hr formula
hr= εσ(Ts+Tsur)(Ts^2+Tsur^2)
saturated media
solid phase and a single fluid phase
Unsaturated media
consist of solid liquid and gas phases
ε
porosity-fraction of the volume of the voids over the total volume
what is heat transfer of convection mostly due to
velocity
heat rate composite wall
T inf1- Tinf/Sum RT
RTotal
sum of all resistances
As Roughness Increases, Contact Resistance _______________.
Increases.
Rt cond in a cylindrical wall
=ln(r2/1r1)/ 2 πLk
Rt
delta T/q
qradiation
epsilon*sigma(Ts^4-Tsur^4)
hr
epsilonsigma(Ts+Tsur)(Ts^2-Tsur^2)
q”
Heat flux (W/m^2)