Good morning, everyone.
Welcome to your Heat Transfer Experiment Number Five, Heat Transfer by Force Convection and
Radiation.
So in this experiment, you will actually be able to compare the heat transfer rate by
forced convection and radiation with different temperature values.
In order to do this experiment, you need the service unit.
You need the HT14 module.
The HT14 module is actually a hollow cylinder with a fan on the bottom, with anemometer
in the middle, and one thermocouple in the middle, and a heater for the heated cylinder,
and one more thermocouple on the top.
So first, let's connect the module to the service unit.
This is the cable for the heater.
The heater is going to be able to change the temperature of the cylinder.
So let's connect this one to the service unit.
OK.
It's been connected.
And the thermocouple over here on the top, this is labeled as 10.
This is T10.
T10 will be able to measure the surface temperature of the heated cylinder.
This is also the T sub s.
S means surface.
This is the T-s, T sub s in the formula that you're going to use to do the analysis.
So let's connect the T10 to the service unit.
T10.
Then in the middle, we have the anemometer.
Anemometer is going to be used to measure the air flow velocity, so we need to connect
this one to the front panel of the service unit here with UA, means the velocity of the
air flow.
This thermocouple over here, that's labeled as number 9, so this is a T9.
We connect this one to T9.
T9 will be able to measure the air flow temperature.
And this is also the T infinity in the calculation, in the formula.
We also need to connect the fan to the service unit on the backside.
Now the module has been connected to the service unit.
Let's power the service unit on.
And this 10 is on.
It's already on.
Actually, the first step for the experiment I want to mention is you need to turn on the
fan first because I don't want the heater to overheat the cylinder.
It will damage the equipment.
So let's turn on the fan.
Once the fan is turned on, now we can start to do our experiment.
In this experiment, you will be able to collect the data for different air flow velocity.
And the voltage input for the heater is going to be constant.
Now I'm going to use the voltage input for group number one for demonstration.
If you are in different groups, please refer to the manual to get your input voltage for
the heater.
So now I'm going to change the voltage input for the heater.
For the group number one, the voltage input is going to be 15.5 volts.
15.5.
Now of course, make sure that your knob is pointing to the V. That's what gives you the
reading of the voltage.
So now this is the voltage input equal to 15.5 volts.
And the current input will also be a constant.
We are now equal to 2.52 amp.
And we need to turn the knob to UA, which right now gives me the reading of the air
flow velocity.
I need to start the air flow velocity equal to one meter per second.
So you need to adjust the plate-- you can see over here-- either you make the gap between
those two white plates larger, you're going to have larger air flow velocity.
Make the gap to be smaller, you're going to have a small air flow velocity.
I need the velocity to be one meter per second first.
For air flow equal to one meter per second, sometimes it's very difficult to control the
value to be exactly equal to 1 meter per second.
So sometimes 1.1 meters per second or 0.9 meters per second, that's also fine.
So this is the air flow velocity.
Then you need to turn the knob to T10 to monitor the temperature of the surface of the heated
cylinder.
We need to let this temperature value become stable.
The criterion for stability is just like before.
We need to watch this number, and if you noticed, this number hasn't changed for 90 seconds,
then this is going to be a stable temperature.
That's something we call steady state.
Once the temperature has become stable, then you will be able to collect your first set
of data.
Your first set of data includes the voltage input, the current, air flow velocity, surface
temperature, T10, and also the air flow temperature, which is also kind of like room temperature
here.
Now the process for stability usually takes 10 to 15 minutes.
So this is going to be your first set of data.
Then you will be able to change the velocity.
Turn the knob back to UA, and change the air flow velocity to 2 meters per second.
Too much.
OK.
This is 1.9.
Open a little bit.
OK.
2.0 meters per second.
So this is air flow velocity equal to 2 meters per second.
Turn the knob back to T10.
And try and wait for another 10 minutes, or 15 minutes, and the temperature of T9 will
become stable again.
This is the second stable temperature.
Once the temperature becomes stable, try and remind you again one more time, the criterion
for stability is the temperature value has not changed for 90 seconds.
Then you can start collecting your second set of data.
Your second set of data, just like before, includes voltage, current, air flow velocity,
surface temperature, air flow temperature.
Repeat the procedure for air flow velocity equal to 3 meters per second, 4 meters per
second, 5, 6, and 7 meters per second.
Collect all the data.
Then that's going to be everything you need for the post-lab calculation and analysis.
This is going to be your Heat Transfer Experiment Number Five.