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ME 309 Heat Transfer . Name:
Closed book/notes with one side of Exam 1 CWID:
one page of notes allowed
Instructions. Closed book, closed notes with one side of one page of notes (A4 size) allowed.
Part 1. Multiple Choices and Short Answer.
1) (
PROBLEM 1.25
KNOWN: Diameter and emissivity of spherical interplanetary probe. Power dissipation
within probe.
FIND: Probe surface temperature.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (2) Negligible radiation incident on the probe.
ANALYSIS:
go want/l
ME 309 Heat Transfer Name:
Closed book and closed notes with four Exam 1 CWID:
sides of one page of notes allowed
instructions. Closed book, closed notes with four sides of one page of notes (A4 size) allowed.
Part 1. Multiple Choices and Short
ME 309 Homework #1- Short Answer Questions
Jan 9, 2014: General Heat Transfer Concepts:
1. What are the physical mechanisms associated with heat transfer by conduction,
convection and thermal radiation?
- Conduction is the transfer of heat through a solid
PROBLEM 1.37
KNOWN: Daily hot water consumption for a family of four and temperatures associated with ground
water and water storage tank. Unit cost of electric power. Heat pump COP.
FIND: Annual heating requirement and costs associated with using electri
PROBLEM 1.17
KNOWN: Length, diameter and calibration of a hot wire anemometer. Temperature of air
stream. Current, voltage drop and surface temperature of wire for a particular application.
FIND: Air velocity
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state condi
PROBLEM 1.5
KNOWN: Inner and outer surface temperatures of a glass window of prescribed dimensions.
FIND: Heat loss through window.
SCHEMATIC:
ASSUMPTIONS: (1) One-dimensional conduction in the x-direction, (2) Steady-state
conditions, (3) Constant proper
PROBLEM 1.13
KNOWN: Hand experiencing convection heat transfer with moving air and water.
FIND: Determine which condition feels colder. Contrast these results with a heat loss of 30 W/m2 under
normal room conditions.
SCHEMATIC:
ASSUMPTIONS: (1) Temperatur
PROBLEM 1.21
KNOWN: Upper temperature set point, T , of a bimetallic switch and convection heat
set
transfer coefficient between clothes dryer air and exposed surface of switch.
FIND: Electrical power for heater to maintain T
set
when air temperature is T
PROBLEM 1.1
KNOWN: Heat rate, q, through one-dimensional wall of area A, thickness L, thermal
conductivity k and inner temperature, T1.
FIND: The outer temperature of the wall, T2.
SCHEMATIC:
ASSUMPTIONS: (1) One-dimensional conduction in the x-direction,
PROBLEM 1.9
KNOWN: Masonry wall of known thermal conductivity has a heat rate which is 80% of that
through a composite wall of prescribed thermal conductivity and thickness.
FIND: Thickness of masonry wall.
SCHEMATIC:
ASSUMPTIONS: (1) Both walls subjected
Incropera Problems 2.21 & 2.22
KNOWN: Diameter D, thickness L and initial temperature T of pan. Heat rate from stove to bottom
i
of pan. Convection coefficient h and variation of water temperature T (t) during Stage 1.
Temperature T of pan surface in cont
Incropera Problems 2.23 & 2.24
KNOWN: Temperature distribution in a one-dimensional wall with prescribed thickness and thermal
conductivity.
FIND: (a) The heat generation rate, q , in the wall, (b) Heat fluxes at the wall faces and relation to
q .
SCHEMAT
PROBLEM 1.33
KNOWN: Width, input power and efficiency of a transmission. Temperature and convection
coefficient for air flow over the casing. Emissivity of casing and temperature of surroundings.
FIND: Surface temperature of casing.
SCHEMATIC:
ASSUMPTIONS
PROBLEM 1.1
KNOWN: Exact and approximate expressions for the linearized radiation coefficient, hr and hra,
respectively.
FIND: (a) Comparison of the coefficients with = 0.05 and 0.9 and surface temperatures which may
exceed that of the surroundings (Tsur
General Heat transfer concepts:
1. Conduction: transfer of thermal energy by intermolecular interaction; Convection:
the sum of thermal energy transfer by intermolecular interaction and thermal
energy transfer by bulk fluid motion.
Radiation: the n
Lecture 1
Thursday, January 12, 2017
1)
11:00 AM
Bookkeeping
a) First Homework Assignment
1) Read Chapter One
2) Math Worksheet Due Thursday Jan 19
b) Course Administration
1) Policies
2) Syllabus
3) Objectives
2)
Course Introduction, Complete
a) Definiti
Lecture 4
Tuesday, January 24, 2017
1)
11:00 AM
Administration
a) Homework
1) Read
i. Chapter 2: Section 2.2 Self Study Focus on Example 2.1
ii. Chapter 3
1) Through 3.3
2) Section 3.2 Self Study
2) Problems
i. Due Thurs : Ch 1: 6, 9, 20, 21, 28, 49a
ii.
Lecture 2
Tuesday, January 17, 2017
1)
11:00 AM
Administration
a) Homework
1) Read Chapter 2: Section 2.2 Self Study Focus on Example 2.1
2) Problems
i. Math Worksheet Due Thursday
ii. Due Thurs Jan 26: Ch 1: 6, 9, 20, 21, 28, 49a
b) Distance Policies
1)
Lecture 3
Tuesday, January 17, 2017
1)
11:00 AM
Administration
a) Homework
1) Read Chapter 2: Section 2.2 Self Study Focus on Example 2.1
2) Problems
i. Math Worksheet Due Today
ii. Due Thurs Jan 26: Ch 1: 6, 9, 20, 21, 28, 49a
b) Homework Submission
2)
3
HW 5 Quiz Solution
Monday, February 20, 2017
1:42 PM
An electric current passed through a 10 [cm] thick steel plate (kavg = 50 [W/(mK)], creates a thermal
conversion rate of 6x106 [W/m3]. The left side of the plate is insulated and the right side is expos
Thermodynamics II
Problem set 11
Due Monday 24 November 2014
1) Steam flows through a device with a stagnation pressure of 120 psia, a stagnation
temperature of 700oF, and a velocity of 900 f/s. Assuming ideal-gas behavior,
determine the static pressure a
Thermodynamics II
Problem set 7
Due Wednesday 15 October 2014
( One point deducted for in-class hw without staple )
1) The air in a room has a dry bulb temperature of 60oF and a wet bulb temperature of
50oF. Assuming a pressure of 14.7 psia, determine
a)
ME 305
Problem set 6
Due Monday 13 October 2014
1) Air and hydrogen (H2) are mixed in a continuous process in which the inlet flows are
10 lbm/s of air at 300oF and 1 lbm/s of hydrogen at 200oF. The pressure at both
inlets and at the mixture outlet are at
Thermodynamics 11
Problem set 10 (note: there is no p.s. 9)
1) Hydrogen is burned with 150% theoretical air during a steady ow process at a
pressure of 2 atm. At what temperature will 98% of H2 burn to H20? Assume the
equilibrium consists of H2, 02, and H
Thermodynamics II
Problem set 8
Due Friday 24 October 2014
( One point deducted for in-class hw without staple )
1. Octane (C8H18) is burned with 250% theoretical air, which enters the combustion
chamber at 25oC. Assuming complete combustion and a total p
Incropera Problems 2.21 & 2.22
KNOWN: Diameter D, thickness L and initial temperature T of pan. Heat rate from stove to bottom
i
of pan. Convection coefficient h and variation of water temperature T (t) during Stage 1.
Temperature T of pan surface in cont
Incropera Problems 2.13 & 2.14
KNOWN: A rod of constant thermal conductivity k and variable cross-sectional area Ax(x) = Aoeax
where Ao and a are constants.
FIND: (a) Expression for the conduction heat rate, qx(x); use this expression to determine the
tem
Incropera Problems 2.15 & 2.16
KNOWN: One-dimensional system with prescribed surface temperatures and thickness.
FIND: Heat flux through system constructed of these materials: (a) pure aluminum, (b) plain carbon
steel, (c) AISI 316, stainless steel, (d) p