EFISIENSI SIRIP BERBENTUK SILINDER
Abstract: To cool the
processor, when the computer is running, usually processor fitted with fins.
With the fin, heat from the processor can be
transferred to the air around the fin become
larger. This study
aimed to obtain
the relationship between (1)
(Lc+0,25D)((2h/(kD))0.5 with
an efficiency η (2)
Lc3/2 (hk/Am)0.5 with an efficiency η (3)
Lc((π/Ao)1/2(h/k))0.5 with
an efficiency η (4)
Lc5/4(((3,14/V)1/2)(h/k))0,5 with
an efficiency η and
(5) (Lc3/2)((3,14/S)(h/k))0.5
with efficiency η. In this study,
geometry of fin is cylinder. Material of fin is metal, long of fin is L=Lc,
and diameter of
fin is D.
All the surfaces
of fin contact with
the fluid. The initial
temperature of fin is uniform,
T=Ti. Then fin
is placed in
the new environment. Temperature
of the new environment is T∞, coefficient of convection heat transfer
is h. Temperature
of fin base
is Tb. Value
of T∞, Tb
and h are maintained at a fixed value from time to
time. In this study, value of Tb is equal to Ti. The
density ρ and specific
heat c of
fin material is
considered uniform and unchanging, while
value of thermal
conductivity k varies
with temperature or k=k(T). Conduction heat flow that goes on
in the fin is assumed to take place in one direction, perpendicular to base of
the fin or in the direction x. The study was conducted with the sequence of
steps : (1) calculating the temperature distribution of the fin on the unsteady
state, (2) calculating the actual heat flow rate released by the fin on the
unsteady state, (3) calculating the heat flow rate released by fin if all the
surfaces of fin
which make contact
with the fluid, have
the same temperature with
a temperature of fin base,
(4) calculating the
value (Lc+0,25D)((2h/(kD))0,5, Lc3/2(hk/Am) 0,5, Lc((π/Ao)1/2(h/k))0,5, Lc5/4(((3,14/V)1/2)
(h/k))0,5, (Lc3/2)((3,14/S)(h/k))0.5
and fin
efficiency η on the
unsteady state, (5) drawing
graphs. Calculation of
temperature distribution on
fin on unsteady state was
done by numerical
simulation with finite
difference method. Finite difference method used is an explicit
method. The result of
study, show that
(1) If the
value of (Lc+0,25D)((2h/(kD))0,5 ; Lc3/2(hk/Am)0,5;
Lc((π/Ao)1/2(h/k))0,5; Lc5/4(((3,14/V)1/2)(h/k))0,5and (Lc3/2)((3,14/S) (h/k))0,5getting
bigger, then the value of fin efficiency ηdecreases. (2) if the value of convection
heat transfer coefficient
h getting bigger,
then the value
of fin efficiency η smaller
(3) For steady-state,
if the value
of thermal conductivity
of materials increases greater then the value of fin efficiency
ηincreases.
Penulis: PK Purwadi
Kode Jurnal: jptmesindd100131
