EML 4304L Thermal Fluids Lab Thermal Conduction Experiment

1
EML 4304L Thermal Fluids Lab Thermal
ConductionExperiment 3
Mechanical Engineering Department FAMU/FSU
College of Engineering
2
Outline

• Purpose of the lab
• Testing Equipment
• The types of equipment setup
• Units 3 and 4
• Units 1 and 2
• Additional components
• Heat sinks
• Drain tubes
• Calculations Needed for Experiment

Mechanical Engineering Department FAMU/FSU
College of Engineering
3
PURPOSE

• Conduct a series of thermal conduction
  experiments which examines the effects on heat
  transfer with varying cross-sectional area and
  distance.
• Using this thermal conduction information derive
  Fouriers law of thermal conduction.
• Analyze the temperature variance in a series of
  metal rods that are in physical contact.
• From this information determine thermal
  resistance and contact resistance.

Mechanical Engineering Department FAMU/FSU
College of Engineering
4
Testing EquipmentFor Experiments
Mechanical Engineering Department FAMU/FSU
College of Engineering
5
Mechanical Engineering Department FAMU/FSU
College of Engineering
6
Mechanical Engineering Department FAMU/FSU
College of Engineering
7
Temperature adjustor for Units 3-4
Mechanical Engineering Department FAMU/FSU
College of Engineering
8
Mechanical Engineering Department FAMU/FSU
College of Engineering
9
Equipment for Thermal Conduction Test Units 3
and 4
Mechanical Engineering Department FAMU/FSU
College of Engineering
10
Heat flow for units 3 and 4
Mechanical Engineering Department FAMU/FSU
College of Engineering
11
Heat flow for units 3 and 4
Notes Do NOT adjust the flow valves.
Mechanical Engineering Department FAMU/FSU
College of Engineering
12
UNIT 3
QKA?T/?x
K coeff. of therm. conductivity
NOTE K is unknown and must be determined
T1
T2
x2
x1
Mechanical Engineering Department FAMU/FSU
College of Engineering
13
UNIT 4
QKA?T/?x
K coeff. of therm. conductivity
NOTE K is unknown and must be determined
T1
T10
x2
x1
Mechanical Engineering Department FAMU/FSU
College of Engineering
14
Equipment Thermal Resistance and Contact
Resistance Test Units 1 and 2
Mechanical Engineering Department FAMU/FSU
College of Engineering
15
Heat flow for units 1 and 2
Mechanical Engineering Department FAMU/FSU
College of Engineering
16
Heat flow for units 1 and 2
elements are enclosed in the insulating jacket.
Figure1 illustrates the schematics of the
apparatus. The dimensions of the tapered rod are
indicated in Fig. 2.
elements are enclosed in the insulating jacket.
Figure1 illustrates the schematics of the
apparatus. The dimensions of the tapered rod are
indicated in Fig. 2.
elements are enclosed in the insulating jacket.
Figure1 illustrates the schematics of the
apparatus. The dimensions of the tapered rod are
indicated in Fig. 2.
Mechanical Engineering Department FAMU/FSU
College of Engineering
17
Units 1 and 2
Cu (Al)
Stainless Steel
Steel (Mg)
T1
T10
x1
x2
Contact Resistance
Mechanical Engineering Department FAMU/FSU
College of Engineering
18
Heat Sinks

• One water cooled heat sink is located on each
  unit
• Units 1 and 2 they are located at extreme end
  of the assembly away from the heat source
• Units 3 and 4 are located on the top of each
  unit
• The heat sinks will be used to determine heat
  lost by each unit.
• QmwCp(?T)

Mechanical Engineering Department FAMU/FSU
College of Engineering
19
Drain Tube Flow Rate Calculations
Mechanical Engineering Department FAMU/FSU
College of Engineering
20
Mechanical Engineering Department FAMU/FSU
College of Engineering
21
Also will need a stopwatch to time fluid flow
Mechanical Engineering Department FAMU/FSU
College of Engineering
22
Calculations
Mechanical Engineering Department FAMU/FSU
College of Engineering
23
Calculations
Conservation of Energy (in a perfect world) qin
q out
Conservation of Energy (in our world) qin Cq
out Where C is a constant which represents any
losses not accounted for.
Mechanical Engineering Department FAMU/FSU
College of Engineering
24
Units 1 and 2
Stainless Steel
Cu (Al)
Steel (Mg)
Heat Sink
Heat In
QoutQin
QmwCp(?T)
Rt,c ?T/Q
Mechanical Engineering Department FAMU/FSU
College of Engineering
25
Calculations
Thermal Contact Resistance Rt,c Thermal contact
resistance ?T Temperature change q Heat flux
Mechanical Engineering Department FAMU/FSU
College of Engineering
26
UNIT 3
Qout
Qin
QoutQin
x2
x1
QmwCp(?T)
QKA ?T/?x
Mechanical Engineering Department FAMU/FSU
College of Engineering
27
Calculations
(1)
(2)
(1) Rate of heat flow at the sink mw mass of
cooling water displaced in time ?t Cp Specific
heat of water at constant pressure ?T (Tout -
Tin) of cooling water ?t time required to
displace a volume Vw of water (2) Relationship
between heat flow and temperature difference K
proportionality constant A cross-sectional
area ?T temperature difference of the
material ?x distance
Mechanical Engineering Department FAMU/FSU
College of Engineering
28
Calculations

• QKA ?T/?x Q-KA dT/dx
• dT/dx temperature gradient

T
dT/dx
x
Mechanical Engineering Department FAMU/FSU
College of Engineering
29
Errors

• Time
• Flow rate
• Steady State
• Heat Losses
• Not perfectly insulated

Mechanical Engineering Department FAMU/FSU
College of Engineering