Download - ME1324-Hmt Group 2
-
7/30/2019 ME1324-Hmt Group 2
1/14
INDEX
S.No NAME OF THE EXPERIMENT REMARKS
4 Thermal conductivity on lagged pipe
5Heat Transfer through Pin Fin
[Forced convection]
6 Thermal Conductivity
[by guarded hot plate method]
-
7/30/2019 ME1324-Hmt Group 2
2/14
THERMAL CONDUCTIVITY ON LAGGED PIPE
AIM :
To determine the Thermal Conductivity and Thermal Resistance of
the given insulating material using the Lagged Pipe Apparatus.
APPRATUS REQUIRED:
The insulation defined as a material, which retards the heat flow with
reasonable effectiveness. Heat is transferred through insulation by
conduction, convection and radiation or by the combination of these three.
There is no insulation, which is 100% effective to prevent the flow of heat
under temperature gradient.
The experimental set up in which the heat is transferred through
i l ti b d ti i d t d i th i t
-
7/30/2019 ME1324-Hmt Group 2
3/14
Knowing the thermal conductivity of one lagging material the thermal
conductivity of the other insulating material can be found.
FORMULAE:
Heat open rated Q = V x I watts.
Mean temperature = TA = (T1+T2+T3) / 3C= TB = (T4+T5 / 2C= TC = (T6+T7 / 2C
Thermal Resistance:
For Asbestos, RA = (TA TB) / Q K/W
For Saw Dust, RS = (TB TC) / Q K/W
-
7/30/2019 ME1324-Hmt Group 2
4/14
PROCEDURE:
1. First the test apparatus rig mu.st be switched on, and allowed for few
minutes till the temperature is gradually spread over the cylinder.
2. After few minute, note down the Voltage and Ammeter readings.
3. Regulate the regulator and display the temperature in display panel
for corresponding Intermediate surface temperatures and note down
in the tabular column.
4. Vary the ammeter reading and allow the apparatus for ten minutes
to come to a steady state and tabulate the readings to find out the
thermal conductivity and thermal resistance
5. Repeat this procedure and take three sets of readings.
RESULT
-
7/30/2019 ME1324-Hmt Group 2
5/14
LAGGED PIPE
SAW DUST
ASBESTOS
HEATER
ASBESTOS
T3
T6
T1
T4 T5
-
7/30/2019 ME1324-Hmt Group 2
6/14
HEAT TRANSFER THROUGH PIN FIN
FORCED CONVECTION APPARATUS
AIM:
To determine the heat transfer Co-efficient from pin fin by Natural
and Forced Convection using the Pin Fin Apparatus.
DESCRIPTION OF APPARATUS :
Consider a PIN-FIN having the shape of rod whose base is attached
to a wall at a surface temperature Ts, the fin is cooled along the axis by a
fluid at temperature TAMB. The fin has a uniform cross sectional area Ao is
made of material having a uniform thermal conductivity K and the average
h t t f ffi i t b t th f t th fl id W h ll
-
7/30/2019 ME1324-Hmt Group 2
7/14
w = 1000 kg / m3.3. Velocity flow rate
Q = Cd x A 2gH m3 / sec.Cd = 0.64, A = d2 / 4, (d = 18 mm)
4. Velocity of air V = Q / A
A = duct area = 150 mm x 100 mm
5. Reynolds number
Re = V Deq / Deq = 4A / p A Area of duct, P Perimeter of duct
6. Nusselt number
Nu = C (Re)n (Pr)
1/3
Refer HMT data book P 105 for values of C & n
7 Th ti l h t t f ffi i t
-
7/30/2019 ME1324-Hmt Group 2
8/14
PIN - FIN APPARATUS
HEATER
T7 T6 T5 T3 T2 T1T4
-
7/30/2019 ME1324-Hmt Group 2
9/14
THERMAL CONDUCTIVITY
[BY GUARDED HOT PLATE METHOD]
AIM:
To find the thermal conductivity of the test plate
DESCRIPTION OF APPARTUS:
The apparatus consists of a guarded hot plate and cold plate. A
specimen whose thermal conductivity is to be measured is sand witched
between the hot and cold plate. Both hot plate and guard heaters are
heated by electrical heaters. A small trough is attached to the cold plate to
hold coolant water circulation. A similar arrangement is made on the
other side of the heater as shown in the figure. Thermocouples are
attached to measure temperature in between the hot plate and specimen
plate, also cold plate and the specimen plate.
-
7/30/2019 ME1324-Hmt Group 2
10/14
FORMULAE:
Heat Transfer through the specimen plate at steady state
Q = KA (T / X)
Where,
Q - heat supplied to heater = V * I in Watts
A - Surface area of plate = D2 / 4, D = 250 mm
X - Thickness of test plate = 30 mm.
K - Thermal Conductivity of test plate in W / m-K
T - (TA TB) C.
Where, TA = [ T1 + T2 ] /2 C
TB = [ T3 + T4 ] /2 C
PROCEDURE:
1. The setup consists of a test plate placed about a heater plate and below a
-
7/30/2019 ME1324-Hmt Group 2
11/14
THERMAL CONDUCTIVITY APPARATUS
-
7/30/2019 ME1324-Hmt Group 2
12/14
TABULATION: Lagged Pipe Apparatus
Sl.
No.
Voltage(V)Volts
Current(I)Amps
Q=V*
IWatts Thermocouple Reading
(0C)
Thermal Resistance Thermal
Conductivity
T1
0C
T2
0C
T3
0C
T4
0C
T5
0C
T6
0C
T7
0C TA TB TC
Asbestos
RA
K / W
Saw dust
RS
K / W
Asbestos
KA
W/mK
Saw dust
KS
W/mK
1
2
3
-
7/30/2019 ME1324-Hmt Group 2
13/14
TABULATION: Pin Fin forced convection
Sl.
No.
Voltmeter
reading
Ammeter
reading Thermocouple Reading
(0C)Manometer Reading
VelocityNU havg
DischargeQ
m3 / SecT1
0C
T2
0C
T3
0C
T4
0C
T5
0C h1 h2
1
2
3
-
7/30/2019 ME1324-Hmt Group 2
14/14
TABULATION: Thermal conductivity by guarded hotplate method
Sl.
No.
Ammeter
R
eading
Vo
ltmeter
Re
ading Thermocouple Reading
(0C)
TA
0C
TB
0C
Thermal
Conductivity
W/mKT1
0C
T2
0C
T3
0C
T4
0C
1
2
3