ME 4210-HEAT TRANSFER LABORATORY #1
Free and Forced Convection Experiments
I. Objectives
To review the following convection heat transfer concepts, practice related measurements and
data analyses, and compare measured results against predictions:
1. Funda
ME4210 Heat Transfer Laboratory #1:
Free and Forced Convection Experiments
Instructor: Dr. AbdulNour
Julian Bates
Stuart Bies
Josh Webb
ME4210: Heat and Mass Transfer
11/18/2011
1
ABSTRACT
The objective of the laboratory includes the examination of convec
PROBLEM 5.34
KNOWN: Metal sphere, initially at a uniform temperature Ti, is suddenly removed from a furnace and
suspended in a large room and subjected to a convection process (T, h) and to radiation exchange with
surroundings, Tsur.
FIND: (a) Time it tak
PROBLEM 5.33
KNOWN: Mass and initial temperature of frozen ground beef. Temperature and convection
coefficient of air. Rate of microwave power absorbed in beef.
FIND: (a) Time for beef to reach 0C, (b) Time for beef to be heated from liquid at 0C to 80C,
PROBLEM 5.35
KNOWN: Thickness and initial temperatures of two layers of copper and aluminum. Contact
resistance at the interface between the layers, applied heat flux, and convective conditions on the upper
surface of the top layer.
FIND: (a) Times at whi
PROBLEM 5.32
KNOWN: Spherical coal pellet at 25C is heated by radiation while flowing through a furnace
maintained at 1000C.
FIND: Length of tube required to heat pellet to 600C.
SCHEMATIC:
ASSUMPTIONS: (1) Pellet is suspended in air flow and subjected to
PROBLEM 5.30
KNOWN: Electrical heater attached to backside of plate while front is exposed to a convection process
(T, h); initially plate is at uniform temperature T before heater power is switched on.
FIND: (a) Expression for temperature of plate as a f
PROBLEM 5.31
KNOWN: Initial dimensions and temperature of SMA rod, ambient temperature and convection heat
transfer coefficient. Properties of SMA.
FIND: Thermal response of the rod assuming constant and variable specific heats, time for rod
temperature t
PROBLEM 5.28
KNOWN: Dimensions and operating conditions of an integrated circuit.
FIND: Steady-state temperature and time to come within 1C of steady-state.
SCHEMATIC:
ASSUMPTIONS: (1) Constant properties.
3
PROPERTIES: Chip material (given): = 2000 kg/m
PROBLEM 5.29
KNOWN: Diameter, resistance and current flow for a wire. Convection coefficient and temperature
of surrounding oil.
FIND: Steady-state temperature of the wire. Time for the wire temperature to come within 1C of its
steady-state value.
SCHEMAT
PROBLEM 5.27
KNOWN: Dimensions and operating conditions of an integrated circuit.
FIND: Steady-state temperature and time to come within 1C of steady-state.
SCHEMATIC:
ASSUMPTIONS: (1) Constant properties, (2) Negligible heat transfer from chip to
substra
PROBLEM 5.21
KNOWN: Initial length, density and specific heat of self-assembled molecular chains. Time constant
of the molecules vibrational response.
FIND: Value of the contact resistance at the metal-molecule interface.
SCHEMATIC:
Rapidly-vibrating
mole
PROBLEM 5.37
KNOWN: Diameters, initial temperature and thermophysical properties of WC and Co in composite
particle. Convection coefficient and freestream temperature of plasma gas. Melting point and latent
heat of fusion of Co.
FIND: Times required to re
PROBLEM 5.40
KNOWN: Electrical transformer of approximate cubical shape, 32 mm to a side, dissipates 4.0 W
2
when operating in ambient air at 20C with a convection coefficient of 10 W/m K.
FIND: (a) Develop a model for estimating the steady-state temperat
3.5 A dormitory at a large unis-rersity, built. 50 years ago, has
exterior walls constructed of L. = 25 II]I11ll]jClcfw_ sheath
ing with a thermal conductivity of k3 = 0.1 W/In-K. To
reduce heat losses in the winter, the university decides
to encapsulate
1.6 The heat flux threugh a weed slah 50 mm thick, whese
inner and enter surface temperatures are 40 and ZUDC,
respectively, has been determined te he 40 W/mf. What
is the thermal cenductivity ef the weed?
1.15 The Snnnthick bettem ef a 200mmdiameter pan
2.5 Assume steadystate, ene-dimensienal heat eenduetien
threugh the symmetric shape shewri.
Assumjiig that there is Il internal heat generatieri,
derive an expressien fer the thermal eeriduetivity ktjx)
fer these eenditiens: AGE) = (1 - x)? Rx) = 300
(1
Heat Transfer: ME 4210
Leela M.R. Arava
Department of Mechanical Engineering
Wayne State University
Email: [email protected]
Phone: 313-577-1986
Sep. 19, 2013
Source/ Textbook: Fundamentals of Heat and Mass
Transfer, by Bergman/ Lavine/ Incropera/ DeW
Review Lecture A
Review of Heat Conduction
Basic Modes of Heat Transfer
Heat transfer is the energy transfer due to temperature difference. There
are 3 basic modes (i.e., mechanisms) of heat transfer: conduction,
convection, and radiation.
Conduction Four
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) Temperature of sphere is spatially uniform, (2) Negligible rad
PROBLEM 1.26
KNOWN: Chip width and maximum allowable temperature. Coolant conditions.
FIND: Maximum allowable chip power for air and liquid coolants.
SCHEMATIC:
ASSUMPTIONS: (1) Steady-state conditions, (2) Negligible heat transfer from sides and
bottom,
Heat Transfer: ME 4210
Leela M.R. Arava
Department of Mechanical Engineering
Wayne State University
Email: [email protected]
Phone: 313-577-1986
Sep. 20, 2013
Source/ Textbook: Fundamentals of Heat and Mass
Transfer, by Bergman/ Lavine/ Incropera/ DeW
PROBLEM 5.9
KNOWN: Solid steel sphere (AISI 1010), coated with dielectric layer of prescribed thickness and
thermal conductivity. Coated sphere, initially at uniform temperature, is suddenly quenched in an oil
bath.
FIND: Time required for sphere to reach
PROBLEM 5.38
KNOWN: Diameter of highly polished aluminum rod. Temperature of rod initially and at two later
times. Room air temperature.
FIND: Values of constants C and n in Equation 5.26. Plot rod temperature vs. time for varying and
constant heat transf
PROBLEM 5.39
KNOWN: Dimensions, initial temperature and thermophysical properties of chip, solder and
substrate. Temperature and convection coefficient of heating agent.
FIND: (a) Time constants and temperature histories of chip, solder and substrate when
PROBLEM 5.26
KNOWN: Diameter and initial temperature of nanostructured ceramic particle. Plasma temperature
and convection heat transfer coefficient. Properties and velocity of particles.
FIND: (a) Time-in-flight corresponding to 30% of the particle mass
PROBLEM 5.24
KNOWN: Initial and final temperatures of a niobium sphere. Diameter and properties of the sphere.
Temperature of surroundings and/or gas flow, and convection coefficient associated with the flow.
FIND: (a) Time required to cool the sphere exc
PROBLEM 5.23
KNOWN: Thickness and properties of strip steel heated in an annealing process. Furnace operating
conditions.
FIND: (a) Time required to heat the strip from 300 to 600C. Required furnace length for prescribed
strip velocity (V = 0.5 m/s), (b)
PROBLEM 5.7
KNOWN: Diameter and initial temperature of steel balls in air. Expression for the air
temperature versus time.
FIND: (a) Expression for the sphere temperature, T(t), (b) Graph of T(t) and explanation of
special features.
SCHEMATIC:
D = 0.012 m