Last Updated 10/7/2011
Heat Conduction Procedure
Setting-up the Apparatus:
This module consists of five basic elements: a control box, power regulator, selector box, a linear conduction apparatus with various samples, and a radial conduction apparatus. You will also need to checkout the NESLAB water chiller that will provide the cooling for the apparatus.
1) Make sure the control box (Figure 3A) and the power regulator (Figure 3C) are turned OFF.
2) Check that the control box is plugged into the power regulator.
3) Connect the military plug to the appropriate jack on the lab station (P1A or P1B).
Figure 1: Military Connector Plugs
4) Turn on the SCXI chassis switch (located above your computer tower). Make sure that the thermocouple blocks (thick yellow cables) are not attached to the second or third slot on your SCXI chassis. If they are, move to another lab station.
Figure 2: Chassis Power Switch
5) Connect the heater power cable (Figure 3E) from the desired conduction apparatus to the front of the control box.
Figure 3: Control Box
A. Control Box
B. Selector Box
C. Power Regulator
D. Heater Knob (counterclockwise is OFF)
E. Heater Power Cable (from either conduction apparatus)
6) If using the linear apparatus (Figure 4A), select and install the desired sample.
a. For best results clean off the surfaces of the sample with the Goof Off and apply coat of thermal grease. (If you run out of thermal grease, talk to Mike in the checkout office)
b. Make sure to place the sample in the correct direction in the linear apparatus because they are keyed, and secure it with the provided clamp.
c. The sample for the radial conduction apparatus (Figure 4B) cannot be varied.
7) Determine which of thermistors (Figure 4C) should be read by the computer. Connect these thermistor cables (Figure 4D) from the conduction apparatus to the connectors on the back of the control box labeled one through seven. The computer only has channels for seven of the nine thermistors.
Figure 4: Heat Conduction Apparatuses
A. Linear Conduction Apparatus
B. Radial Conduction Apparatus
C. Thermistors
D. Thermistor cables
E. Tubing with quick disconnect fittings
8) Plug the power regulator into one of the outlets (either circuit #7 or #8) located next to the computer on the lab station.
9) Plug the water chiller into the remaining outlet located next to the computer on the lab station.
IMPORTANT: Do not plug both the Power Regulator and the Water Chiller into the same outlet. Use two different outlets that are on separate circuit breakers.
10) Select the mode on the selector box (Figure 3B) to computer.
11) Open Heat Conduction Apparatus.vi from the following path:
H:\ITLL Documentation\ITLL Modules\Armfield Heat Conduction
12) When the VI opens, enter the following information into the “User Inputs” dialogue box:
a. Indicate the temperature units desired
b. Select the Apparatus that you will be using, Rod or Disk.
c. Specify the time interval between samples in minutes
d. Enter the watts applied for the experiment. (This is the same wattage that will be dialed in on the control Box when running the experiment.) This field is not used for any computations in LabView but will be saved in the data.
Experimental Procedure
Starting at Room Temperature
1) Start cooling the water in the water chiller before attaching it to the apparatus by turning on the cooler with the cooler tubing attached to itself. Setting the temperature to 5-10° C. Let it run for 10-20 until the water temperature has stabilized.
2) Turn the heater knob on the control box fully counterclockwise. This is the OFF position.
3) When the water has reached the desired temperature, turn OFF the chiller and connect it to the heat conduction apparatus using the quick disconnect fittings.
4) Press the run arrow in the top left hand corner of the LabVIEW program and then OK to begin collecting data.
5) Turn on the power regulator, control box and water chiller. Use the heater knob to set the watts applied your desired heating load between 0-30 W.
WARNING: If the heater temperature reaches 100° C the control box will shut down. Monitor your temperature readings carefully.
6) When the temperatures have reached steady state and you are done taking data, hit the ‘STOP’ button on the VI to quit and save the data to a file. The file will record the watts applied, the temperature units and each data point. It is recommended to save with extension “.xls’ so that Excel can open the file.
Heating up the Apparatus
1) Connect the water chiller to the heat conduction apparatus using the quick disconnect fittings. Turn on the water chiller and Setting the temperature to 5-10° C. Let it run for 10-20 until the temperature at the end of the rod has stabilized.
2) Unplug the heater cord (figure 3E). Turn on the power regulator and control box. Turn up the power on the heater to 10-30 W.
3) Press the run arrow in the top left hand corner of the LabVIEW program and then OK to begin collecting data.
4) Once the temperature has stabilized at the cool side of the rod, you will start the experiment by plugging in the heater power cord to the control block. Take care to record the temperatures at each of the points just prior to plugging in the heater cord; this will be the initial temperature distribution.
5) When the temperatures have reached steady state and you are done taking data, hit the ‘STOP’ button on the VI to quit and save the data to a file. The file will record the watts applied, the temperature units and each data point. It is recommended to save with extension “.xls’ so that Excel can open the file.
Program Behavior
1) While the program is running, it will tell you how many samples it has taken, how long it has been running, and how long until the next sample.
2) The plot shows the various temperatures of each thermistor with a different color in a temperature versus time format.
Clean Up
1) Turn off the water chiller (read the instructions on the water chiller on how to properly turn off), power regulator and control box.
2) Disconnect any hoses and wiring.
3) Return module and water chiller to module storage bay.
Useful Information
Heat Conduction through a Rod
Dimensions of the brass cylinder:
v Diameter: 25 mm
v Length: 80 mm
v Distance between probes: 11mm
Composition of the Brass SpecimenK value of 117 W/m2
60to 65% Copper
35 to 40% Zinc / Composition of the Stainless Steel Specimen
K value of 25 W/m2
.08% Carbon, 2% Manganese
1% Silicon, 16 to 18% Chromium
10 to 14% Nickel, 2 to 3% Molybdenum
Figure 5: Diagram of Rod Set Up
Figure 6: Diagram of Rod
Heat Conduction through a Disc
Dimensions of the brass disc:
v Inner radius: 5 mm
v Outer radius: 55mm
v Height: 3 mm
v Distance between probes: 11 mm
Figure 7: Diagram of Disc Set Up
Figure 8: Diagram of Disc
Reference for materials information can be found in the following books located in the Engineering Library.
v ASM Handbook, Volume 18, TA 459 A5 V.18, 1992
v Standards Handbook; Copper, TA 480 C7C655
v Engineering Formulas 4th Edition, TA151.G4713, 1983
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