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°. 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. ================================================================= 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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