Studi Eksperimen Aliran Fluida Melalui Ducting System Berpenampang Bujur Sangkar Dengan Menempatkan Oriented Square Cylinder Sebagai Badan Pengganggu Di Dalam Square Elbow 90

Munawar, Farhan Ihza Lazuardi (2019) Studi Eksperimen Aliran Fluida Melalui Ducting System Berpenampang Bujur Sangkar Dengan Menempatkan Oriented Square Cylinder Sebagai Badan Pengganggu Di Dalam Square Elbow 90. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Mekanika fluida merupakan salah satu teknologi yang cukup vital untuk mendukung kehidupan manusia. Aplikasinya dapat kita temui dengan mudah di kehidupan sehari-hari, seperti pada sistem perpipaan maupun sistem saluran udara. Dengan adanya sistem perpipaan, kita dapat memindahkan aliran fluida secara kontinu dengan mudah. Namun, ketika fluida mengalir pada sistem ini khususnya pada elbow akan mengalami penurunan tekanan atau pressure drop yang disebabkan adanya gesekan antara partikel fluida dengan dinding dari instalasi, separasi akibat momentum fluida sudah tidak dapat menahan adverse pressure hingga disebabkan oleh secondary flow. Untuk mengurangi hal tersebut, pemasangan badan pengganggu berupa oriented square cylinder perlu dilakukan dan diharapkan dapat melawan adverse pressure gradient dan wall shear stress sehingga pressure drop yang terjadi dapat diperkecil.
Penelitian ini dilakukan secara eksperimen dengan asumsi aliran bersifat incompressible, viscous serta steady flow. Instalasi eksperimen berupa square duct yang secara umum terbagi menjadi 3 bagian, yaitu upstream (L1 = 7 Dh = 875 mm), elbow 90O (Dh=125 mm) , dan downstream ((L2 = 25 Dh = 3125 mm), curvature ratio yang digunakan sebesar (R/Dh 3), sedangkan untuk badan pengganggu yang digunakan adalah oriented square cylinder dengan variasi diagonal sebesar (d = 10 mm dan 12.5mm) dan gap ratio sebesar (g/d = 0.2). Re yang digunakan yaitu 2 x 〖10〗^4 hingga 1 x 〖10〗^5.
Hasil yang didapatkan pada penelitian ini bahwa dengan penggunaan badan pengganggu berbentuk oriented square cylinder dengan diagonal d = 10mm dan 12.5mm pada Re = 2 x 〖10〗^4 hingga 1 x 〖10〗^5 dapat mengurangi pressure drop yang terjadi pada bagian upstream dan downstream. Penurunan pressure drop total optimal terjadi pasqda pemasangan diagonal badan pengganggu d=12.5mm dengan Re = 2 x 〖10〗^4. Dari nilai coefficient of pressure (Cp) semakin besar Re pada aliran, perbedaan Cp antara sisi inner dan outer wall semakin besar. Pemasangan badan pengganggu pada α=〖10〗^o mengakibatkan Cp setelah melewati badan pengganggu tersebut mengalami penurunan yang drastis. Penurunan Cp terbesar terjadi pada penggunaan diagonal badan pengganggu dengan d=12.5mm. Untuk profil kecepatan, profil kecepatan sisi horizontal pada downstream variasi tanpa badan pengganggu menunjukkan adanya deficit aliran pada centerline sampai mendekati inner wall, pada variasi dengan menggunakan badan pengganggu deficit aliran tersebut dapat diperbaiki pada daerah centerline, namun tidak teratasi pada inner wall elbow dan menambah agitasi pada sisi outer wall.
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Fluid Dynamics is one type of technology that is vital in order to support human life. Its application can be seen in our daily live, for examples as piping system and ducting system. With pipeline existence, fluid can be continuously moved easily. But as fluid flows through piping system, elbow especially, will experience pressure drop that occurred as the effect of friction between fluid particles and pipe wall, flow separation as the fluid’s momentum cannot overcome the adverse pressure gradient, and also by secondary flow. The ways to reduce pressure drop that occur in elbow 90o is by adding oriented square cylinder as disturbance body inside 90o so that the flow can overcome adverse pressure gradient and wall shear stress.
This research has been done experimentally with assumptions such as incompressible flow, viscous flow and steady flow. The experiment’s installation consist of square duct that divided into three parts, there are upstream (L1 = 7 Dh = 875 mm), elbow 90o (Dh=125 mm) , and downstream ((L2 = 25 Dh = 3125 mm. The value curvature ratio used in this experiment is 3 (R/Dh = 3). Disturbance bodies used in this research is oriented square cylinder which its diagonal length are (d=10 mm and d=12.5 mm), with gap ratio (g/d = 0.2). Re that is used in this experiment range from 2 x 〖10〗^4 up to 1 x 〖10〗^5.
The results showed that by addition of oriented square cylinder as disturbance body with d = 10 mm and d =12.5 mm can reduce pressure drop that occurred in flow at upstream and downstream section from Re = 2 x 〖10〗^4 up to 1 x 〖10〗^5. Reduction of total pressure drop reach its optimum at the point where d = 12.5 mm body disturbance is placed and the fluid flows at Re = 2 x 〖10〗^4. As the fluid flows at higher Reynolds Number, the Coefficient of Pressure (Cp) difference’s between inner and outer wall also get higher. The insertion of disturbance body at angular position α=〖10〗^o makes high amount of Cp decreased near inner wall. The decreasing of Cp reached its minimum at the point where d = 12.5 mm body disturbance is placed. After fluid flows through elbow, the horizontal velocity’s profile at downstream showed that flows deficit occurred from centerline to inner wall. With disturbance body insertion, flows deficit reduction worked at centerline, but its didn’t work near inner wall as the flow also agitated near outer wall.

Keyword: Square Duct, elbow 90º, disturbance body, pressure drop, experiment.

Item Type: Thesis (Other)
Additional Information: 3100020084541 RSM 620.106 4 Mun s-1
Uncontrolled Keywords: Square duct, elbow 90º, badan pengganggu, pressure drop, eksperimen.
Subjects: T Technology > TJ Mechanical engineering and machinery > TJ935 Pipe--Fluid dynamics. Tubes--Fluid dynamics
Divisions: Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Farhan Ihza Lazuardi Munawar
Date Deposited: 22 Dec 2022 05:50
Last Modified: 22 Dec 2022 05:50
URI: http://repository.its.ac.id/id/eprint/74032

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