Studi Eksperimen Karakteristik Aliran Melalui Square Duct Dengan Oriented Square Cylinder Sebagai Inlet Disturbance Body Di Dalam Elbow 90°

Hakim, Sonny Aditya Luqman (2017) Studi Eksperimen Karakteristik Aliran Melalui Square Duct Dengan Oriented Square Cylinder Sebagai Inlet Disturbance Body Di Dalam Elbow 90°. Other 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 (Dh = 125 mm) trough elbow 90º with
disturbance body inside the elbow called as “Inlet Disturbance
Body”. The scheme is divided into three main parts: upstream duct
(straight duct) with length 7Dh, square elbow 90º (Rc/Dh = 3) with
Inlet Disturbance Body (h = 125 mm, DIDB = 12,5 mm) which
varies location within the inner wall elbow that is on 5°, 10°, 15°
20° from inlet elbow, and downstream duct (straight duct) with
length 15Dh. This experiment uses variation Reynolds Number
(ReDh 4,77x104) to calculate velocity profile throughout
downstream duct, Pressure Drop and Coefficient Loss Minor
iv
elbow 90º with Reynolds 1,46x104 to 10,3x104, Pressure
Coefficient elbow 90º uses three Reynolds 4,77x104; 6,36x104; and
9,54x104.
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 1,59x104 up to
9,54x104. The variation IDB 15° and 20° optimal reducement at
Reynolds number 1,59x104 up to 5,5x104, 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/Dh = 0,024 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 (Other)
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:	19 Aug 2025 06:54
URI:	http://repository.its.ac.id/id/eprint/44515

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