Hakim, Sonny Aditya Luqman (2017) Studi Eksperimen Karakteristik Aliran Melalui Square Duct Dengan Oriented Square Cylinder Sebagai Inlet Disturbance Body Di Dalam Elbow 90°. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Penelitian ini dilakukan secara eksperimen untuk menganalisa karakteristik aliran dalam square duct (Dh = 125 mm) yang melewati elbow 90º dengan body pengganggu didalam elbow. Sekema penelitian ini dibagi menjadi empat bagian utama yaitu: upstream straight duct (panjang 7Dh), square elbow 90º (Rc/Dh= 3), Inlet Disturbance Body (Didb= 12,5 mm)divariasikan letaknya pada 5°, 10°, 15°, 20°dan downstream straight duct (panjang 16Dh). Variasi ReDh sebesar 4,77x104digunakan untuk mendapatkan profil kecepatan sepanjang downstream duct, Pressure Drop dan Coefficient Loss Minor elbow 90º pada Reynolds 1,46x104 sampai 10,3x104, Pressure Coefficient elbow 90º pada Reynolds 4,77x104; 6,36x104; dan 9,54x104.Hasil penelitian ini diperoleh bahwa penggunaan Inlet Disturbance Body (IDB) dapat menurunkan pressure drop, variasi letak IDB 10° merupakan posisi terbaik dalam menurunkan pressure drop pada bilanganReynolds 1,59x104sampai 9,54x104.variasi letak IDB15° dan 20° penurunan pressure drop optimal pada bilangan Reynolds1,59x104sampai 5,5x104dibandingkan tanpa menggunakan IDB. Adanya IDB menjadikan timbulnya shear layer yang meningkatkan intensitas turbulensi pada outer elbow. Intensitas turbulensi tertinggi pada z/Dh = 0,024 pada variasi IDB20º yaitu sebesar 14%, profil kecepatan pada variasi ini menunjukan deficit momentum pada center line (x/Dh= 0 sampai x/Dh = 4) dapat terkurangi sehingga proses recovery aliran lebih cepatdan menanggulangi timbulnya secondary flow.
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Square duct is many used in applications around us, for examples as supply cold air to conditioned room (AHU).
One of fittings of ducting system is elbow 90°, meanwhile air flows through elbow 90°
have some
losses like
pressure drop, it come
about with existence of
friction loss
,
separation loss
,
and
secondary flow
.
The ways to reduce pressure drop
who occur in
elbow
90°
is
by adding a
disturbance body called
“
Inlet
Disturbance Body
”
,
by shaped
Oriented Square Cylinder
(
rotated
45°)
purposed to delay
the separation point on the inner and outer
wall elbow
also
make flow become turbulence when entering the
elbow
.
More turbulent a stream will have greater momentum
so it
can
increase the ability to
against
adverse pressure
.
This research was
doing by
experimentally to analyze flow
characteristics in sqare duct
(
D
h
= 125 mm)
trough
elbow 90
º
with
disturbance
body
inside the
elbow
called as
“I
nlet Disturbance
Body
”
.
The scheme is divided into three
main parts:
upstream duct
(straight duct)
with
length
7D
h
,
square
elbow 90
º
(
Rc/Dh = 3
)
with
Inlet Disturbance Body
(h =
125 mm
,
D
IDB
=
12,5 mm
)
w
hich
varies location within the inner wall elbow that is on
5°
,
10°
,
15°
20°
from
inlet elbow
,
and
downstream
duct (straight duct)
with
length
15D
h
.
This experiment
uses
variation
Reynolds
Number
(
Re
Dh
4
,7
7
x
10
4
)
to calculate
velocity profile
throughout
downstream duct,
P
ressure
D
rop
and
Coefficient
Loss
M
inor
iv
elbow 90º
with
Reynolds
1,46
x10
4
to
10,
3
x10
4
,
Pressure
Coefficient
elbow
90º
uses three
Reynolds
4
,
77
x10
4
; 6,3
6
x10
4
;
and
9,5
4
x10
4
.
The results showed that
by
addition of IDB
can reduce
pressure drop
in special case
,
the variation of
IDB
10°
is the best
position to reduce pressure drop
at
Reynolds
1,59
x10
4
up
to
9,54
x10
4
.
The variation
IDB
15°
and
20°
optimal
reducement
at
Reynolds
number
1,59
x10
4
up to
5,5
x10
4
,
after passing that
Reynolds the
trendline
of variation
IDB
showed
cut through
the
trendline
with no
IDB.
It’s happen because the shear layer of this
variation is not optimal to against adverse pressure on
inner
side
wall
elbow,
so that the
blockage area
at
outlet elbow
cannot be
reduced
.
The value of coefficient losses elbow showed that all of
variation with IDB have larger value than without using IDB
.
This happen because of the existence
of drag force between fluid flow
and the IDB. However, this
IDB makes occurrence of shear layer
(vortex) that increase the turbulence intensity in outer elbow.
The highest turbulence intensity at
z/D
h
= 0,0
24
with
variation of
IDB
20º
that is 14%, velocity profile at this variation shows deficit momentum at center line (x/Dh= 0 up to x/Dh= 4) can reduced, so that fluid recovery processes can be faster and reduce secondary flow.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSM 620.106 4 Hak s |
| Uncontrolled Keywords: | Square Duct, Pressure Drop, Profi Kecepatan, Inlet Disturbance Body |
| Subjects: | T Technology > TH Building construction T Technology > TJ Mechanical engineering and machinery |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Sonny Aditya Luqman Hakim |
| Date Deposited: | 20 Nov 2017 08:37 |
| Last Modified: | 06 Mar 2019 06:41 |
| URI: | http://repository.its.ac.id/id/eprint/44515 |
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