TUTORIAL 5
HOU Youmin
14/03/2014
Convection Boundary layers
h~
Local and Average Heat Transfer Coefficient
Important dimensionless numbers
Nusselt Number Nu
Prandtl Number Pr
Reynolds Number Re
Radiation:
Blackbody Radiation and Grey Surfaces
S. Yao MECH3310 Lecture 20 Ch 12.3-12.7 25/04/2014
1
The Planck Distribution
The spectral distribution of the blackbody emissive power (determined
theoretically and confirmed experimentally) is
E,b varies
TUTORIAL 11
HOU Youmin
02/05/2014
Basic Equations
The Planck Distribution:
Wiens displacement law:
Stefan-Boltzmann Law:
in a certain specified wavelength range
Kirchhoffs Law and Gray Surface
Kirchhoffs law equates the total, hemispherical emissivity
2-D Conduction: Shape Factor
and Numerical Method
S. Yao MECH3310 Lecture 10 Ch 4 5.10 07/03/2014
1
Need to solve the heat equations for T (x,y)
For 2-D steady conduction, constant k, w/o Eg, derive the heat equation:
2T 2T
k 2 2 0
x
y
Solution Meth
Radiation Exchange
S. Yao MECH3310 Lecture 22 Ch 13.2 02/05/2014
1
Radiation Exchange Between Opaque, Diffuse, Gray,
Isothermal Surfaces in an Enclosure
i i 1 i
Net radiative transfer at surface i:
Radiosity Ji = emission + reflection
J i Ei i Gi i Ebi
Phase Change:
Boiling and Condensation
MECH3310 Lecture 18 Ch. 10 11/04/2014
1
Boiling Heat Transfer
Evaporation occurs at
the liquidvapor interface
when the vapor pressure
is less than the saturation
pressure of the liquid at a
given temperature.
MECH33
Radiation Exchange
S. Yao MECH3310 Lecture 22 Ch 13.2 29/04/2016
1
Radiation Exchange Between Opaque, Diffuse, Gray,
Isothermal Surfaces in an Enclosure
( i = i =
1 i )
Net radiative transfer at surface i:
Radiosity Ji = emission + reflection
J i = Ei +
Natural Convection
S. Yao MECH3310 Lecture 17 9.1-9.6 13/04/2016
1
What are the required conditions for natural convection?
Buoyancy arise in a fluid for which there are density gradients and is a
body force that is proportional to density, e.g.,gravitat
TUTORIAL 4
HOU Youmin
07/03/2014
Homework 2
Lumped capacitance model
For the situation: T varies with time
Assumption:
Validity of lumped capacitance method
Semi-infinite Solid
TUTORIAL 9
HOU Youmin
25/04/2014
5.
Basic Concepts
Thermal radiation is that electromagnetic radiation emitted by a body
as a result of its temperature.
Electromagnetic Wave Spectrum
<0.38 m
=0.38 0.76 m
=0.76 1000 m
>1000 m
ultraviolet radiation, X
Convection Fundamentals:
Similarity and Analogies
S. Yao MECH3310 Lecture 12 6.5-6.8 14/03/2014
1
Boundary Layer Similarity
As applied to the boundary layers, the principle of similarity is based on
determining similarity parameters that facilitate appli
Radiation Exchange and
Multimode Heat Transfer
S. Yao MECH3310 Lecture 23 Ch 13.3 07/05/2014
1
Radiation Shields
High reflectivity (low e or a) surface(s) inserted between two surfaces for
which a reduction in radiation exchange is desired.
Two large par
TUTORIAL 1
HOU Youmin
14/02/2014
Office hour
TAs: Hou, Youmin ([email protected])
Yu, Miao ([email protected])
Office hours: Tue 16:00-18:00,
RM1213 (Lift 21, near the exit)
Applications of Heat Transfer
Air conditioning
Refrigeration
Water harvesting
Power ge
Environmental Radiation
and
View Factor
S. Yao MECH3310 Lecture 21 Ch 12.8 13.1 30/04/2014
1
Interaction of solar radiation with earths atmosphere:
Absorption by aerosols over the entire spectrum.
Absorption by gases (CO2, H2O (v), O3) in discrete wave
Internal Convection:
Heat Transfer Correlations
S. Yao MECH3310 Lecture 15 Ch 8.4-8.5 04/04/2014
1
Laminar Flow in a circular tube:
The local Nusselt number is a constant throughout the fully developed
region, but its value depends on the surface thermal
HEAT TRANSFER
TUTORIAL 2
HOU Youmin
21/02/2014
Resistance Model
conduction
convection
radiation
&
Important thing!
For resistance model, the q is the same in the series connection.
Like I in electrical model, the q in parallel connection has the same prop
Internal Convection:
Heat Transfer Correlations
S. Yao MECH3310 Lecture 16 Ch 8.4-8.5 08/04/2016
1
Laminar Flow in a circular tube:
The local Nusselt number is a constant throughout the fully developed
region, but its value depends on the surface thermal
Radiation:
Blackbody Radiation and Grey Surfaces
S. Yao MECH3310 Lecture 20 Ch 12.3-12.8 22/04/2016
1
The Planck Distribution
The spectral distribution of the blackbody emissive power (determined
theoretically and confirmed experimentally) is
E,b varies
Phase Change:
Boiling and Condensation
S. Yao MECH3310 Lecture 18 Ch. 10 15/04/2016
1
Boiling Heat Transfer
Evaporation occurs at
the liquidvapor interface
when the vapor pressure
is less than the saturation
pressure of the liquid at a
given temperature.
2-D Conduction: Shape Factor
and Numerical Method
S. Yao MECH3310 Lecture 10 Ch 4 5.10 09/03/2016
1
Need to solve the heat equations for T (x,y)
For 2-D steady conduction, constant k, w/o Eg, derive the heat equation:
2T 2T
k 2 2 0
y
x
Solution Meth
Internal Convection:
Hydrodynamic and Thermal
Considerations
S. Yao MECH3310 Lecture 14 Ch 8.1-8.2 01/04/2016
1
Hydrodynamic considerations
Hydrodynamic Effects: Assume laminar flow with uniform velocity profile at
inlet of a circular tube.
Velocity bou
Conservation of Energy
S. Yao MECH3310 Lecture 2 Ch 1.3-1.4 05/02/2016
1
Review of Thermodynamics
Energy can have many forms
Energy can change from one form to another
S. Yao MECH3310 Lecture 2 Ch 1.3-1.4 05/02/2016
2
Review of Thermodynamics
Energy can e
MECH3310 Spring 2016
S.Yao
Final Guideline
Prepare for Final Examination
Time: May 28, Sat. 12:30PM - 3:30PM
Location: LG1 Table Tennis Room (LG1031)
Closed book/notes.
Bring 2 double-sided A4 sheets of notes and a calculator.
The cheat sheets should defi
MECH3310 Spring 2016
S.Yao
Practice Midterm
Prepare for the Midterm
Time: March 30, Wednesday, 15:00-16:20
Location: 2303 (Surname starting with A-H); 2405 (J-N); 2504 (P-Z)
Closed book/lecture notes.
Prepare 1 sheet (two sides) of notes on standard A4 pa