Studi Numerik Aliran Melalui Saluran Udara Berpenampang Bujur Sangkar Dengan Penempatan Obstacle Di Dalam Elbow 90°

Dharma, Ikki Adji (2020) Studi Numerik Aliran Melalui Saluran Udara Berpenampang Bujur Sangkar Dengan Penempatan Obstacle Di Dalam Elbow 90°. Masters thesis, Institute Teknologi Sepuluh November.

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Abstract

The value of pressure drop on an elbow 90 ° is greater than the pressure drop on a straight duct which has the same equivalent length. Frictional losses and secondary losses contribute to the high-pressure drop in the 90 ° elbow area. The high value of pressure loss has an impact on increasing the electrical power required for fan/blower work. The numerical research was carried out to reduce the pressure drop in the air duct installation consisting of a straight duct and a 90º elbow with a square cross-section, with a curvature ratio (Rm / Dh) of three. Reynolds stress model was chosen as the turbulence model in numerical simulation. The passive boundary layer control method with media in the form of an obstacle with a cross-sectional oriented square cylinder (OSC) and a circular cylinder (CC) placed near the inner wall elbow 90 ° with a distance (g / d = 0.2). To enrich the information, this study also analyzes the optimal angular position of the obstacle at (α) 4 °, 8 °, and 12 °. The Reynolds number used in this study is 0.79 × 104 to 4 × 104, based on the hydraulic diameter of the air duct. Based on the simulation results, it is known that the shape of the obstacle affects the increase in the intensity of the flow turbulence. OSC is able to provide a greater turbulent intensity increase than CC with the consequence of an increase in pressure drag. The numerical simulation results show that the optimal Reynolds number and angular position are at 4 × 104 and 4 °, where in these conditions the smallest pressure drop value is obtained along the air channel. ================================================================= Nilai pressure drop pada elbow 90° lebih besar dibanding pressure drop pada straight duct yang memiliki panjang ekuivalen yang sama. Frictional losses dan secondary losses berkontribusi terhadap tingginya pressure drop di daerah elbow 90°. Tingginya nilai pressure loss berdampak pada meningkatnya daya lisrik yang dibutuhkan untuk kerja fan/blower. Penelitian secara numerik dilakukan dengan tujuan mengurangi pressure drop pada instalasi saluran udara yang terdiri dari straight duct dan elbow 90º yang berpenampang bujur sangkar, dengan curvature ratio (Rm/Dh) sebesar tiga. Reynolds stress model dipilih sebagai model turbulensi pada simulasi numerik. Metode passive boundary layer control dengan media berupa obstacle berpenampang oriented square cylinder (OSC) dan circular cylinder (CC) ditempatkan di dekat inner wall elbow 90° dengan jarak (g/d = 0.2). Untuk memperkaya informasi, penelitian ini juga menganalisa keadaan optimal angular position obstacle pada sudut (α) 4°, 8°, dan 12°. Adapun bilangan Reynolds yang digunakan pada penelitian ini 0.79 × 104 hingga 4 × 104, berbasis pada diameter hidrolik saluran udara. Berdasarkan hasil simulasi, diketahui bahwa bentuk obstacle mempengaruhi peningkatan intensitas turbulensi aliran. OSC mampu memberikan peningkatan turbulent intensity yang lebih besar daripada CC dengan konsekuensi terdapat peningkatan pressure drag. Hasil simulasi numerik menunjukkan bahwa pada bilangan Reynolds dan angular position yang optimal berada pada 4 × 104 dan 4°, dimana pada kondisi tersebut diperoleh nilai pressure drop aliran yang paling kecil di sepanjang saluran udara.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Angular position, obstacle, straight duct, elbow 90º, pressure drop sudut angular,pengganggu,saluran lurus,siku 90,penurunan tekanan
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA357 Computational fluid dynamics.
T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
T Technology > TJ Mechanical engineering and machinery > TJ935 Pipe--Fluid dynamics.
Divisions: Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User: Ikki Adji Dharma
Date Deposited: 25 Aug 2020 03:24
Last Modified: 25 Aug 2020 03:24
URI: http://repository.its.ac.id/id/eprint/80847

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