OBJECTIVE :
-
To study the Fourier’s Law on linear and radial conduction heat transfer.
Illustrate the transfer of heat by conduction in solid materials while varying the
parameters affecting conduction.
INTRODUCTION:
Thermal conduction is a mode of heat transfer which occurs in a material due to the
presence of temperature gradient. It is a transfer of energy
energy from the more energetic particles to
the adjacent less energetic particles.
Generally, heat is defined as energy transfer due to the temperature gradients or
difference between two points. eat energy can be transferred in three modes, which are
conduction, convection, and radiation. !ne of the most common heat
hea t transfer modes, which is
conduction heat transfer, is defined as heat transferred by molecules that travel a very short
distance "#$.%&'m( before colliding with another molecule and e)changing energy.
In this e)periment, both linear and radial conduction heat transfer methods are studied.
The entire system "insulated heater*specimen, air and laboratory enclosure( are at room
temperature initially "t + $(. The heater generates uniform heat flu) as switched on.
For linear conduction, an electrical
elec trical heating element, which comprises of a heat input
section fabricated from brass fitted with an electrical heater, is bonded to one end of a metal rod
"heat source(. nother end of the rod, which is also made of brass, is e)posed to heat discharge
"heat sin-(. The outer surface of the cylindrical rod is well insulated thus yielding o ne/
dimensional linear heat conduction in the rod once the heating element is switched on.
Thermocouples are embedded in the rod, along its centerline.  simple mimic diagram for heat
conduction along a well/insulated cylindrical rod is shown as below0
For radial conduction, the electrical heating element is bonded to the center part of a
circular brass plate "heat source(. The cooling water flows through the ed ge of the plate that acts
as a heat sin- for heat discharge.
d ischarge. The other surfaces of the plate are well insulated to simulate
radial heat conduction from the plate center to its edge when the heating element is switched on.
The brass plate has a radius, r plate + %$ mm and thic-ness, t + 1.2 mm. Thermocouples are
embedded in the circular plate.  simple mimic diagram for heat conduction along a well/
insulated circular plate is shown as below0
EQUIPMENT :
The eat 3onduction 4tudy 5ench
PROCEDURE :
Part A – Linear Conduction aon! a "o#o!eneou$ and Co#%o$ite Bar&
6. The power cable for the 3ylindrical Test 7nit was connected to the display unit.
2. The 2&mm diameter brass specimen was clamped into the intermediate section of the
linear module. The thermal paste was applied to the surfaces to ensure proper contact.
1. The thermocouples were inserted into their respective slots.
8. The e9uipment was turned on by turning the main power -nob cloc-wise.
&. The water flow was set to 6.8L*min.
%. 5y loo-ing at the display, the 3ylindrical Test 7nit was selected by pressing :43 and the
pressing the F6 button.
;. The heater is switched on and the power is set to 6$ <.
=. The temperatures were monitored through the display unit until the temperatures achieve
steady state condition.
>. The temperatures were recorded and the thermal conductivity obtained.
6$. The heater is switched off after recording the results and before changing the specimen.
66. 4teps 2 to 6$ were repeated by using 2&mm stainless steel and 6% mm diameter brass
specimen.
Part B – Radia Conduction aon! Circuar Meta Pate&
6.
2.
1.
8.
&.
The power cable for the ?adial Test 7nit was connected to the display unit.
The thermocouples were inserted into their respective slots.
The water flow was set to 6.8 L*min.
The system was set to ?adial Test 7nit.
The heater was switched on and the power was set to 6$ <.
%. The temperatures were being monitored through the display unit until the temperatures
reaches steady state condition.
;. The temperatures were recorded and the thermal conductivity obtained.
=. The heater is switched off after the recording. The power was switched off after T6 is less
than &$ ⁰3.
RE'ULT':
Linear Conduction:
@ower "<(
4pecimen
6$
2&mm diameter
5rass
6$
6%mm diameter
5rass
6$
2&mm diameter
4tainless 4teel
8=.6
8;.6
8&.=
81.6
2&.2
28.=
21.%
21.6
2$.8
8&.>
8&.1
88.1
1$.1
2&.&
28.&
21.>
21.6
;6.8
8;.=
8;
8%
1=.%
16.2
2&.%
22.>
22.1
82.%
T6 "⁰3(
T2 "⁰3(
T1 "⁰3(
T8 "⁰3(
T& "⁰3(
T% "⁰3(
T; "⁰3(
T= "⁰3(
Theoretical Thermal
3onductivity
"<*m.B(
-"<*m.B(
2&mm
Aiameter 5rass
6%mm
Aiameter 5rass
2&8.%
1$&.&
86.=
;=.1
>2.%
2;;.;
1$&&.$
26=.2
81%.8
2%.6
6;1.%
6$6.=
1$&.&
1$&&.$
2&mm
Aiameter
4tainless 4teel
21&.$
1=6.>
2=.1
8;.$
18.1
11>.8
1$&&.$
Aistance "mm(
$.$
6&.$
1$.$
8&.$
%$.$
;&.$
>$.$
6$&.$
Radia Conduction :
@ower "<(
?6 "⁰3(
?2 "⁰3(
?1 "⁰3(
?8 "⁰3(
?& "⁰3(
?% "⁰3(
Theoretical
Thermal
3onductivity
"<*m.B(
-"<*m.B(
=%.$
;1.&
&&6.%
2&.6
%=.>
(RAP"' :
Linear Conduction
6$
1;.&
12.=
11.$
16.=
2;.6
2&.8
6$%.;
Aistance "mm(
6$.$
6&.$
2&.$
1&.$
8&.$
&&.$
e)periment, the higher temperature gradient is created b y the heater and the lower gradient
temperature is made by the cooling water.
?eferring to the results, it shows that the results appears to follows the Fourier’s Law of
3onduction as the temperature readings -eep decreasing as it goes from T6 to T=. 4ome of the
percentage errors of the thermal conductivity value are 9uite large. It may due to the lac- of
e9uipment and the lac- of awareness of the e9uipment’s usability.
Last but not least, there are some precautions that need to be ta-en when doing this
e)periment. Give the e9uipment some time before ta-ing the temperature readings. This is done
to ma-e the system in steady state condition. In steady state condition, the temperature readings
are stable and constant. This will give a better accu racy in the calculations. In addition, the
connections of the thermocouples need to be firm. The reading will be affected by the
surrounding temperature and it ma-es the e)periment inaccurate.
CONCLU'ION:
In conclusion, the Fourier’s Law of 3onductivity is certainly well studied on linear and
radial conduction heat transfer and the values of thermal conductivity of certain materials had
been calculated. The transfer of heat by conduction is well illustrated in this e)periment where
heat is being transferred in solid material which is in metal bar and metal plate. Thus, the
objective is achieved.