[MUSIC PLAYING] Good morning, everyone.
Welcome to your heat transfer experiment number three, transient heat conduction.
In this experiment, you will be able to measure how temperature changes with time.
Also, you will be able to calculate the conduction heat transfer coefficient, h-value.
You will also be able to calculate the build number, and also you will be able to compare
your experimental data with a theoretical prediction, which provided by the method we
call [INAUDIBLE] method, which we have learned in the heat transfer class.
In order to do this experiment, you need the following devices.
Of course, the service unit, and then you need a module called at HT17G.
And also you need to about seven samples to see how temperature changes with time for
different materials, different shape, and [? actually ?] we'll give you a different
build number and different conduction heat transfer coefficient.
OK?
Now, let's first get familiar with the equipment first.
I think I do not have to repeat how to operate these service unit.
This is the third time that we're working on this service unit.
OK?
So, I'm going to check this one.
The model here-- this is called HT17G.
This is actually a water heater.
You see the big container over here.
This one actually is a water container with a volume about it 30 liters of water.
OK?
I already actually put the 30 liters of water in there, and also I [? press ?] [? set.
?] I actually preheated the water heater.
OK?
Now, one very important instruction for the instructor, or for the TA, who is going to
teach this class in the future, is you need to prepare for this experiment at least four
to five hours before the experiment because generally it will take four to five hours
for the water to be heated up from regular room temperature-- let's say you go to 23
degrees to 85 or 90 degrees.
And also you need to keep this unit on all the time.
So let's say for example, if you had a experiment like on Tuesday morning 9 o'clock or 8 AM,
you need to turn on this device on Tuesday and also keep this on for the overnight.
OK?
So this is some instruction for the instructor or for the TA.
OK?
And this one, as I said, is actually a water heater with the heater actually on the bottom.
And it will also have the thermostat.
The thermostat I usually set up to either the number four or either the number five.
Now, if you preset this thermostat to number five, this one will actually give you what
temperature roughly about 85 degrees to 90 degrees Celsius.
OK.
So this is a water heater.
This water heater also equipped with a mini pump.
This mini pump will circulate the water inside the container so that we're going to have
a more uniform water temperature inside.
Also, the top-- that's going to be covered.
Now, that's going to be a metal cover.
I want you to be really careful because this metal cover could be very hot, because inside
that's a water temperature roughly about 85 to 90 degrees.
So all the surface over here, [INAUDIBLE] could be really hot.
You need to be really careful, and you could get burnt.
OK?
On top of the cover over here, we have two thermal cables.
Let's show you this one.
This is thermal cable labeled number one.
This thermal cable actually measures is the fluid temperature around the pump.
This is also something we call a T infinity.
OK?
So we need to connect this one to the channel T1, to the service unit.
We have another thermal cable here labeled as number two.
Now this number two thermal cable is actually attached into this one.
This is called the [? carrier.
?] The [? carrier ?] will actually carry the sample over here, and this is the thermal
cable.
Now the thermal cable will actually measure the fluid temperature around the sample.
So this is something that we need actually to use in the future for the calculation.
This is a T2, and also we use this one as the T sub infinity.
OK?
That's the fluid temperature.
So we need to connect this one to T2.
So this is the thermal cable and the entire setup of this water heater.
Now, come to the sample.
Total, you have seven samples.
Those samples made from either brass or stainless steel.
You can check the label on top of the sample over here.
If you see that letter B over here, means this is a material actually from the brass.
OK?
If you see the letter S over here, this means this is a stainless steel.
OK?
And then you can say we have a total of seven samples.
Three of them are cylindrical shape.
Two of them are spherical shape, and two of them are like a [INAUDIBLE].
OK?
So that's the seven samples, and for each of the samples-- let's say for example this
one-- this is a brass cylinder, diameter equal to 30 millimeter.
For each of the samples, we have actually a thermal cable labeled as number three embedded
in the center of the sample.
So this is a center-line temperature of the sample.
OK?
And because this is labeled as number three, you actually need to connect this one to the
channel three, T3 over here, as well be able to measure the center-line temperature of
the sample.
OK?
So this is the sample and the equipment.
OK.
Now, let's connect those equipment into the power and wire them up so that it will be
ready to do the experiment.
I need to connect the main unit-- this is the power cord for the main unit-- to the
power outlet.
I also need to connect the mini pump to the back side of the main unit-- service unit.
OK?
And for the water heater, because it requires 220 volts power imput-- so you need a step
up transformer.
So for the transformer, input of voltage is 110 volts.
And for the water heater, the module, actually requires as I said, at 220.
So connect it to 220, power on, already on.
And also, you need to make sure the main switch for the water heater here, you have two small
individual switch.
Make sure both are on.
OK?
As I said, I already preset the thermostat equal to number five, and this one will give
me a temperature by roughly about 85 degrees Celsius.
Now, let me turn on the service unit.
I need to provide the power to the mini pump.
The pump requires a voltage input of 12 volts.
So turn to the knob to the [? V, ?] and then change the voltage input.
Voltage should be 12 volts.
This is 12 volts, and you can see the pump is running.
When the pump is running, the water is actually circulating inside the container so that we're
going to have a more uniform temperature distribution.
Now because this pump is actually too noisy for the video recording, I'm going to turn
off, but I want you to--
I'm going to turn of those pumps just because we're doing this video recording, it's too
noisy.
Now remember for regular operation to experiment, you need so keep the pump on all the time.
OK?
So this is the set up.
Now actually everything's ready.
So we should be able to do our first experiment.
The first experiment I want to try the sample number one over here.
This sample is labeled as material that's brass and a shape that's cylinder.
Diameter is equal to 30 millimeter.
So I want to put the label over here.
For this experiment, we require some teamwork.
You need at least two to three team members to work together to do this experiment.
Team member number one is going to stay here.
Use your cell phone to do the data recording because the temperature changes very fast
for this experiment.
Typically temperature changes or increases from 25 degrees Celsius to about 85 degrees
Celsius in less than 30 seconds or sometimes it's 60 seconds.
Anyway they change really fast.
So you have no time to write down those temperatures value.
So you need to use some kind of a video recorder.
Now, I want you to use your own cellphone to do the video recording.
So team member number one is going to stay here to do this video recording, and you also
remember you need to put the label over here.
If you do not put the label over here, later you're going to confuse because you're going
to have seven videos very similar to each other.
And you may not be able to tell which video is for which sample.
That's why labeling here is very important.
OK?
And also you need to turn the knob to T3.
T3, that's a measurement of a central-line temperature of sample.
OK.
Now, hopefully, team member number one is ready to stay here to do the video recording.
Now I'm trying to act as team member number two.
I'm going to drop this one into the hot water.
First, I need to do is attach the sample to the [? carrier.
?] OK?
So I need to unscrew this.
Now I need to attach this one to the [? carrier.
?]
Now when holding the sample, I want you to note there's a tip, very important tip.
Do not hold the bottom of the sample because this is the sample.
If you hold like this way, you actually heating the sample with your hand, and you actually
change the initial temperature of the sample.
So don't do that way.
Hold the top side.
OK?
Now, also I want you to note there's a small hole on top of the sample over here, the handle
over here, and also there's another small hole also in [? carrier ?] here.
What you need to do is line those two holes up, and then slide those-- slide the bolts
in through these two holes.
Sometimes this one may requires maybe a few seconds to practice.
OK?
So now it's ready.
Attach this screw back to the [? carrier.
?] Now it's ready to drop this one to the hot water.
So I'm the team member number two.
OK?
As I said, team member number one actually is ready to shoot the data, to record the
data.
Team member number two can use a step then stand up, and you will be able to check that
this is a vent.
And when you're ready to drop this one into the hot water, I have also another very important
tip.
When you hold the sample over here, try and to make the sample away from the vent over
here because the vent actually will have steam, the vapor come up.
And that's actually a very hot steam.
And if you leave your sample on top of that, you're actually are preheating the sample,
and this will change the initial temperature.
So try and to make the sample stay away from the vent.
Then I need to give out some signal so that later we can synchronize the data.
So you need to alert the team member number one who is recording the data to know that
hey, I'm ready to drop this one into the hot water.
So you have to give out a signal something like that.
One, two, three, go.
OK?
And also actually, the team member number one who is recording the data, you can actually
start your video recorder three or four seconds before team member number two drop this one
into the hot water.
OK?
So you need to let the team member number two know.
So suppose my team member number one is ready.
So I'm going to drop this one into the hot water.
So I'm going to give out some signal.
One, two, three, go.
So now you will be able to see the temperature changes very fast.
Original temperature is about room temperature, roughly 30, 20, 27, 25, 26, something like
that.
Now in just a few seconds, it's about 60 now.
OK?
The temperature of the water inside the container is about 85 degrees Celsius.
So when you see the temperature over here that is a very close or getting close to 84,
83, you can actually stop data recording.
OK?
That's enough data for our calculation.
So right now, you can see probably in less than 30 second, we'll have the temperature
value right now about the 79 degrees Celsius.
OK?
And now you see the temperature change, the rate will change.
Getting [? slow down.
?] OK?
So when the temperature come to 83 or 82.5, then I will stop the data recording.
So 83.
So I will ask my group member number one, team member number one to stop the data recording.
So now I'm going to take this one out from the hot water, and cool down the sample a
bit.
And I can put the [? carrier ?] back into the water.
Detach T3, which is the thermal cable [? with ?] the sample.
OK?
And also I want the team member to [? wire ?] this carefully so that it will be ready
to use for the next group.
OK?
It will take about a 30 seconds for the sample 2 cool down.
Because right now, I'm holding the sample.
I still feel this is very hot.
OK?
And let the sample stay in the cold water for maybe one minute, and let this one to
be completely cooled OK?
I think it's a cooled down now.
And dry this.
And put this one back.
Then also remember to put the label back.
OK?
So now we have finished the test for the first sample.
Now you can do the same for the other six samples.
Let's say, for example, sample number two, you need to put the label over there, then
attach this one to the [? carrier, ?] drop this one into the hot water, and record the
temperature change.
So that's going to be for the sample number two.
I do have another very important tip for the sample like this, the slab.
For the slab, I want you to notice the width if this slab is kind of like exactly equal
to that diameter of the vent.
Now, if you look closely, you will be able to see that we have actually three pins protrude
out over here.
See here?
This is one, two.
There's another one.
That's three.
OK?
So because the dimensions and the diameter of this exactly equal to each other-- so when
you're trying to drop this one, a sample like this, into the hot water, you need to choose
the correct angle.
Otherwise it will stay in the middle.
Let me so you.
If you choose this angle like over here.
As, you can see, it will stay over here actually.
It will not slide into the water.
So we need to choose our angle carefully so that you will be able to slide this all the
way into the hot water.
So the team member number two who is going to do drop this one in to the hot water--
when do the experiment with those two samples, you need to be very careful.
Choose a correct angle so that you will be able to slide them all the way to the end.
OK?
So this is the tip that I want you to know for the sample with two slabs.
So finish all of those seven samples.
This well complete your heat transfer experiment number three, transient heat conduction.