CONDUCTION RESISTANCE IN CYLINDER/SPHERE
, for cylinder
A long cylindrical pipe (or spherical
shell) with specified inner and outer
surface temperatures T1 and T2.
A = 4r2, for sphere
15
The thermal resistance network for a
cylindrical (or spherical) shel
Chapter 4
TRANSIENT HEAT CONDUCTION
MEC 305
Objectives
Lumped system analysis: negligible spatial variation of
temperature temperature is just function of time.
Analytical solutions for transient one-dimensional
conduction problems (rectangular, cylindr
TRANSIENT HEAT CONDUCTION IN SEMI-INFINITE SOLIDS
Constant Ts case
Semi-infinite solid
Plane surface (1D)
T = T(x, t)
T(x,t=0)=Ti
0
x
xof
Plane wall can be modeled as semi-infinite if temperature variation is limited in the
region near one of the surfaces
Chapter 7
EXTERNAL FORCED
CONVECTION
MEC 305
DRAG AND HEAT TRANSFER IN EXTERNAL FLOW
When fluid flow over solid bodies, our interest is in (i) drag force acting on the
body (and lift for airplane) and (ii) the cooling and heating of body.
Free-stream velo
Chapter 6
FUNDAMENTALS OF
CONVECTION
MEC 305
PHYSICAL MECHANISM OF CONVECTION
Convection = Conduction + Advection
(Advection: heat transfer assisted by
bulk fluidic motion)
Conduction and convection both require
presence of a material medium but
convecti
Chapter 8
INTERNAL FORCED
CONVECTION
MEC 305
INTRODUCTION - INTERNAL CONVECTION
Liquid or gas flow through pipes or ducts is commonly used in heating and
cooling applications, usually forced to flow by a fan or pump.
Theoretical solutions are obtained onl
Chapter 9
NATURAL CONVECTION
MEC 305
PHYSICAL MECHANISM OF NATURAL CONVECTION
Many familiar heat transfer applications involve natural convection as the
primary mechanism of heat transfer, usually accompanied by radiation of
comparable magnitude except fo
Chapter 12
FUNDAMENTALS OF THERMAL
RADIATION
MEC 305
THERMAL RADIATION
Thermal radiation is emitted as a result of energy transitions
of molecules, atoms, and electrons of a substance.
In this class, we limit our consideration to thermal radiation;
ener
Chapter 2
HEAT CONDUCTION EQUATION
MEC 305, Heat and Mass Transfer
Stony Brook University
1-DIMENSIONAL HEAT CONDUCTION EQUATION
Heat conduction is approximated as one-dimensional if heat conduction is
dominant in one direction and negligible in other dir
HW#3 Solutions
3-31 Warm air blowing over the inner surface of an automobile windshield is used for defrosting ice accumulated on
the outer surface. The convection heat transfer coefficient for the warm air blowing over the inner surface of the
windshield
MEC 305 (Spring 2017)
Recitation #2 with Solutions
Problem 1-69.
Solution 1-69.
Problem 1-103.
Solution 1-103.
Problem 1-141.
A soldering iron has a cylindrical tip of 2.5 mm in diameter and 20 mm in length. With age and
usage, the tip has oxidized and ha
Recitation #6 (Chapter 4. Transient Heat Conduction)
Lumped analysis (Temperature is only function of time; no spatial distribution within a body)
Problem 4-22
Solution 4-22
Similar to EX 4-1
The temperature of a gas stream is to be measured by a thermoco
Recitation #5
In general, for the boundary subjected to both convection & radiation, Rconv
& Rrad are parallely connected !
IF Tsurr T , 1/Rcombined = 1/Rconv + 1/Rrad (parallel circuit)
! 1/(1/hcombinedA) = 1/(1/hconvA) + (1/hradA)
! hcombined
MEC305 Recitation 7
Problem 4-89
Solution 4-89
4-155 A heated large iron slab is placed on a concrete floor; (a) the surface temperature and (b) the temperature
of the concrete floor at the depth of 25 mm are to be determined.
Assumptions 1 The iron slab
Problem 2-22
Starting with an energy balance on a rectangular volume element, derive the onedimensional transient heat conduction equation for a plane wall with constant
thermal conductivity and no heat generation.
EXAMPLE 2-9
Problem 2-42
Problem 2-43
Pr
Chapter 13
RADIATION HEAT TRANSFER
MEC 305
VIEW FACTOR
View factor quantifies fraction of
radiation leaving a surface that strikes
another surface
Necessary for radiation analysis
View factor is purely geometric quantity
that is independent of surface