Chapter 6
Introduction to Convection
By Dr. Mostafa H. Sharqawy
KFUPM ME 315
1
Boundary Layers: Velocity Boundary Layer
u y
u
u
s
y
0.99
y 0
FD s dAs
As
The region between the surface and the free s
King Fahd University of Petroleum and Minerals
Mechanical Engineering Department
ME 315-03: HEAT TRANSFER
Spring Semester 2015-2016 (152)
Course Description: Introduction to heat transfer by conductio
INTRODUCTION
Fans and compressors are gas movers; however, compressors are characterized by
high-pressure increase through the machine. It is widely accepted that if the density
change through the mac
KING FAHD
UNIVERSITY OF PETROLEUM & MINERALS
ME 316: Thermofluids Laboratory
Experiment # 5
CENTRIFUGAL AIR COMPRESSOR
1) OBJECTIVES
a) To introduce the operational principle of a centrifugal compress
PROBLEM 3.84
KNOWN: Composite wall with outer surfaces exposed to convection process.
FIND: (a) Volumetric heat generation and thermal conductivity for material B required for special
conditions, (b)
PROBLEM 4.23
KNOWN: Temperature, diameter and burial depth of an insulated pipe.
FIND: Heat loss per unit length of pipe.
SCHEMATIC:
T2 = -10C
z=3m
D1 = 1.0m
Oil, T1 = 110C
D2 = 1.4m
ASSUMPTIONS: (1)
PROBLEM 3.3
KNOWN: Temperatures and convection coefficients associated with air at the inner and outer surfaces
of a rear window.
FIND: (a) Inner and outer window surface temperatures, Ts,i and Ts,o,
PROBLEM 1.6
KNOWN: Heat flux and surface temperatures associated with a wood slab of prescribed
thickness.
FIND: Thermal conductivity, k, of the wood.
SCHEMATIC:
35 W/m2
35 C
15 C
0.06 m
ASSUMPTIONS:
PROBLEM 9.24
KNOWN: Plate dimensions, initial temperature, and final temperature. Air temperature.
FIND: (a) Initial cooling rate, (b) Time to reach prescribed final temperature.
SCHEMATIC:
ASSUMPTION
. vat; LVa-wtan (OR\EM gvuu:si0\ mt r:
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M (Magma, A.
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1/; an . '
3. Lu? Akbi Stat M Ua-vya'aa
1h 94 bf
Pixt' c. 52.8 (lm)
42.
OYMIK. u
(ah. : 3: 3bit:
A dx.
NW: M '
Chapter 2
Conduction Heat Transfer
By Dr. Mostafa H. Sharqawy
KFUPM ME 315
1
The Conduction Rate Equation (Fouriers Law)
A rate equation that allows determination of the conduction heat flux from kno
Chapter
Ch t 5
Transient Conduction
By Dr. Mostafa H. Sharqawy
KFUPM ME 315
1
Transient Conduction
A heat transfer process for which the temperature varies with time, as well as
location within a sol
PROBLEM 9.23
KNOWN: Length of isothermal vertical plate, L.
FIND: Expression for the ratio of the average heat transfer coefficients for N plates each of length LN
= L/N to the average coefficient for
Transient Conduction:
The Lumped Capacitance Method
Chapter Five
Sections 5.1 through 5.3
Transient Conduction
Transient Conduction
A heat transfer process for which the temperature varies with time,
One-Dimensional, Steady-State
Conduction without
Thermal Energy Generation
Chapter Three
Sections 3.1 through 3.4
Methodology
Methodology of a Conduction Analysis
Specify appropriate form of the heat
Two-Dimensional Conduction:
Shape Factors
and
Dimensionless Conduction Heat Rates
Chapter 4
Sections 4.1 and 4.3
General Considerations
General Considerations
Two-dimensional conduction:
Temperature
Fouriers Law
and the
Heat Equation
Chapter Two
Fouriers Law
Fouriers Law
A rate equation that allows determination of the conduction heat flux
from knowledge of the temperature distribution in a medi
Heat Transfer:
Physical Origins
and
Rate Equations
Chapter One
Sections 1.1 and 1.2
Heat Transfer and Thermal Energy
What is heat transfer?
Heat transfer is thermal energy in transit due to a tempera
PROBLEM 7.8
KNOWN: Flat plate comprised of rectangular modules of surface temperature Ts, thickness a and
length b cooled by air at 25C and a velocity of 25 m/s. Prescribed thermophysical properties o
PROBLEM 5.8
KNOWN: The temperature-time history of a pure copper sphere in an air stream.
FIND: The heat transfer coefficient between the sphere and the air stream.
SCHEMATIC:
ASSUMPTIONS: (1) Tempera
King Fahd University of Petroleum & Minerals
MECHANICAL ENGINEERING DEPARTMENT
31.5 «— Transfer
Fall Semester 2014-2015 (141)
QUiZ # 1 Name
Dr. P. Gandhidasan Student # ,
Thursday: 16 October 2014
King Fahd University of Petroleum & Minerals
MECHANICAL ENGINEERING DEPARTMENT
ME 315 —— Heat Transfer
Fall Semester 2014-201 5 (141)
Quiz # 5 ‘ Name /,
Dr. P. Gandhidasan Student #
Sunday: 28 Decem
Quiz # 3
Dr. P. Gandhidasan
Tuesday: 09 December 2014
King Fahd University of Petroleum & Minerals
MECHANICAL ENGINEERING DEPARTMENT
ME 315 —— Heat Transfer
Fall Semester 2014-2015 (141)
Name _
Studen
PROBLEIVI 12.22
KVOWN: Evacuated. aluminlun sphere (D = 2m) sewing as a radiation test chamber.
FIND: Irradiation on a small test object when the inner slu‘face is lined with carbon black and at
600K.
PROBLENI 11.7
KNOWN: Number. inner and outer diameters. and thermal conductivity of condenser tubes.
Convection coefficient at outer surface. Overall ﬂow rate. inlet temperature and properties of wate
PROBLEM 9.6
KNOWN: Heat transfer rate by convection from a vertical surface. 1m high by 0th wide. to
quiescent air that is 20K cooler.
FIND: Ratio of the heat transfer rate for the above case to that
Fouriers Law
and the
Heat Equation
Chapter Two
Fouriers Law
Fouriers Law
A rate equation that allows determination of the conduction heat flux
from knowledge of the temperature distribution in a medi
One-Dimensional, Steady-State
Conduction without
Thermal Energy Generation
Chapter Three
Sections 3.1 through 3.4
Methodology
Methodology of a Conduction Analysis
Specify appropriate form of the heat
PROBLEM 3.84
KNOWN: Composite wall with outer surfaces exposed to convection process.
FIND: (a) Volumetric heat generation and thermal conductivity for material B required for special
conditions, (b)
One-Dimensional, Steady-State
Conduction without
Thermal Energy Generation
Chapter Three
Sections 3.1 through 3.4
Methodology
Methodology of a Conduction Analysis
Specify appropriate form of the heat
PROBLEM 3.6
KNOWN: Curing of a transparent film by radiant heating with substrate and film surface subjected to
known thermal conditions.
FIND: (a) Thermal circuit for this situation, (b) Radiant heat