STEADY STATE HEAT
CONDUCTION
STEADY STATE HEAT CONDUCTION IN A
SLAB
General governing equation for one-dimensional heat transfer
(infinite slab):
T
k T Q
t c x c
2
2
p
p
At steady state and assuming no heat generation, the equation
becomes
d 2T
0
dx 2
Bo

RADIATIVE ENERGY TRANSFER
THE ELECTROMAGNETIC SPECTRUM
- Unlike conductive or convective heat transfer, no medium is
required for the radiative exchange between bodies since the
exchange is through electromagnetic waves.
- The magnitude of the radiative e

HEAT TRANSFER WITH CHANGE
OF PHASE
Phase change brings in additional complications in studying heat
transfer due to changes in density, thermal conductivity and
specific heat. Phase change processes are also energy intensive.
Latent heat of fusion, Hf
- t

UNSTEADY STATE HEAT
CONDUCTION
TRANSIENT HEAT TRANSFER WITH
NEGLIGIBLE INTERNAL RESISTANCE
Consider a solid with convection over surface
Heat transfer from the surrounding medium to the solid object
involves:
1. external (convective) resistance and
2. int

thermal
mo
y energy kg
l J
System wlDx
Surroundin
gs else
Differentia
Algebraic
l
Integral
Steadystate
Dynamic
Open
Closed
Reactive
Non-reactive
x1 =
0 mm =
T1 = 14.5 oC
x2 =
25 mm =
T2 = 45.2 oC
k= 0.029 W/m-K
0m
0.025 m
"
= /
1. In determining the therm

Composting is used to treat various organic wastes such as grass clippings, leaves, paper, and
animal manure, etc. These wastes are converted by microbial degradation to a stabilized compost.
The microbial degradation process generates heat and composting

1. Consider a cylindrical limb with a radius (R) of 5 cm being cooled with a
refrigerant so that
the surface was maintained at 2C. Assume only one dimensional (radial
direction) heat transfer, the effective thermal conductivity of limb is 0.55
W/mK and th

4. One common means to measure thermal conductivity of an implantable
biomaterial is to insert a long metallic probe axially into the center of a long
cylindrical container of the material. The probe is maintained at some
uniform temperature Ti, and the o

Given:
k=
t=
T(1) =
T(2) =
k=
q=
Find the heat flux (W/m2) through a
2.162
0.01284
large slab of ice at steady state with
2m
one end maintained at 0C and the
0C
other, -50C. The slab thickness is 2 m.
-50 C
The thermal conductivity of ice varies
with temp

CONVECTIVE HEAT TRANSFER
GOVERNING EQUATION FOR
CONVECTION
Convective heat transfer
- the movement of heat through a medium as a result of the
net motion of a material in the medium
In most heat transfer applications involving a liquid or gas, convection

Name:
BE 3180 Heat and Mass Transfer in Biological Systems
Test I
Feb. 25, 2013
1. (30%) Unlike temperature regulation in the mammals, snakes do not regulate body
temperature. Their body temperatures vary with the environment. By knowing the temperature
d

BE 3180 Heat and Mass Transfer in Biological Systems
HOMEWORK 9
(Due on Friday, Apr. 18)
1. In the making of carbonated soft drinks, dissolved CO2 is an important ingredient which provides
the necessary zing to the beverage. We need to maintain a desirabl

Name:
BE 3180 Heat and Mass Transfer in Biological Systems
Test I
Feb. 17, 2012
1. A sea divers suit has a thickness of 5 mm and is made of a material with thermal conductivity
of 0.05 W/mK. If the divers skin is 33C and the water temperature is 10C and t

Name:
BE 3180 Heat and Mass Transfer in Biological Systems
Test I
Feb. 11, 2011
1. (30%) 1. An active MRI implant is a small device incorporated into metal surgical implants to
make imaging via MRI easier by producing local interference to stop the disrup