TECF{-EB

{h;e'[-Tiirfl'"EFf]F; ii,ri. j i...'i;A I_*_ I t ;_j I i_ar i._,' 1.* I-.- *.:: -: ."11-..1 j ;.'-: :li _j j: 9.:+

I-.'fl-:r;1,I .,-" -l

i

Tililh::;i L_: g;r,; tsflI..=.,9gllil- Cs}IyFF,ai*i i;'#, E I8, GA$+-F-IF:iE Vni-,!-."';:i.

itrA€-;ai?*i*Atqi i i.{{-,err=n*, ir,"JEr;;r;F; i';.,gA 1i'A jr.,.ni.'-.I.i:i.q"

u-.thii i;."u i.{} fi. EI * S,5i_i #.;'?i : q$giiF-ri3";4 "{ 5,3:l;. {:,i:!.i*-i'i4?i

Ti +,i; : ilriti;"_,i :i.,: i I :ij;1 ::,

Ti* *"r ;r i i : { +:,i.: i-l* eii :i $j,,.::l.;.;i ;+ li: i: ri. t_,c. i r_r

ir.';i; -ll_

r {! :i 5','A 1., - ., i i i ;,.i.,,:, ; i i_ i i il r

TECH"EF

Aim:-

To find out total thennal resistance and total thermal conductivityiffcomposite slab

Description:-

The apparatus consists of central heater sandwiched between two sheets,

These Upes of slab provided on both sides of heater, which folms composite

structure. A srnali hand press is provided to ensure perfect contact between

the slabs. A dimmer stat is provided to vary heat input of heaters and it ismeasuled by a digital voit meter and atnmeter. Thertlocouples are

embedded between interfaces of slabs. A digital temperature indicator is

plovided to measure temperature at various points.

Specification:-

1. Slab assernbly arranged symmetrically on both sides of the s1ab.

2. I'Jichrome heater wound on mica heater of 30O-Watt capacitSz.

3. Dimmer stat open type, 230v,0-2 anp, single phase'

4. \/olt rneter5. Ammetet'6. Digital temperature indicator 0-2000 C7. Enclosule size : 300x300x300 rnm8. Slab diameter:300 mtl.9. Thickness of cast iron : 25tnrn.l0.Thickness of Bakelite:19 mm.1 l.Thickness of wood: 12 rrrm.

TE,CH-EB

Procedure:-

Arrahge the plates in proper fashion on both sides of heater plates.

rtact between plates.

2. Close the box by cover sheet to achieve proper environmentalcondition

.,.3. Starl the rnain switch.4. By adjusting the dimmer knob give heat input to heater. (Say B0V,

90V etc.)5. Take the readings of all (8) thennocouples at an interval of i0 rnin.

Until the final steady state.6. Note down the reading in observation table.7. Make dirlrrrer knob to "zero" position and then put main switch off.8. Repeat the procedure for diffelent heat input.

Otiservation Table:-

Formulae:-

i. Heat input

Q: VxI .'...'.'Watts2

2. TA avg : Ti + T2 ....oC1

TB avg : T3 + T4 ....oC2

TC avg : T5 + T6.. ..oC2

sl.No,

\/Volts

Iamps

T1oc

T2oc

T3oc

T4oc

T5oc

T6oc

T7oc

T8oc

fo, c"t(c.-f..{,.? jr: tb T ,.*f-s- rrc t qft= *,o, *lt" yr,a,W t_-,=_:f- {b* ft7 *ilretVa, &-4*a( (**'o.4. Tlremal Resistance of Slab ( R ) fc LrrtitliTr,r4td"*f +C'*-f-

Q i*a cr<l^t

ff.r.-ffrti-J k- c<le c< ( ,*'a", cr-n*' n L hat f 6ta

"R - TA avs + TD avs .... 'C/Wa QUPA 6'{'-z-L* A;c{n fth-;ca,*( St'e'

i4}'ji#t''du-^

+1*."J,,tr1 l" ,,r- iin *< o:l der€ +Cc-rrlrr y* p f4-{.dr. '

TD avg : T7+ T8 ....oC2

.3. Alea of Slab

A: JI d24

Where "d" is diameter of slab. (Effective dia.

5. Thelrnal Conductivity ( K )

K: Oxt.... Wlm kA (TA avg - TD avg )

Where "t" is thickness of slab.

TECH-ED

: 300 mm)

cccl( fi t-t ot&tru'.e 4L*4

(J : -13'z

&"kt* ' I'4'Go"A > o.l66

o. t(Po-,n, - ,. .4

( i! ' t

' 7axl,u I iriu,,4. g r2.GS -

l\4bq{r l@* Ce+zaaS heqs.d : 6,{14poraltv-4u*>- * J.._+* t^**i

Precautions:-

i) Keep the dim're'stat to zero before starti'g the experiraent.ii) while removing plates do not dist'r-b trreriiocoupies.

Use the selector su'itch knob and dimmer icnob gently.

.-::;r)/--

jaft

oc.

.)F_j#\t\€r-\tl I

ts-\gl()F"ef@g1nU

z

2u.,L-Nz=<!^o.givd

UL

4:4Er

U

o

s

4

F

EJaoUo2eEF

+r

ca

-:-

Zv

{!

c

':

-

!

=a5

l;

3

=

:0.tn

c

*

zOFadOaU.f

at

rat

za;U

JrZO

ooB

ra

ozL

xN