STUDI EKSPERIMEN ALIRAN MELALUI OCTAGONAL ELBOW 900 DILENGKAPI DUA GUIDE VANE PADA CLOSED CIRCUIT WINDTUNNEL

ADAM, ABEL BRYAN (2016) STUDI EKSPERIMEN ALIRAN MELALUI OCTAGONAL ELBOW 900 DILENGKAPI DUA GUIDE VANE PADA CLOSED CIRCUIT WINDTUNNEL. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penggunaan elbow dalam perancangan closed circuit windtunnel, akan menyebabkan terjadinya kerugian tekanan pada aliran. Hal tersebut disebabkan oleh perubahan arah aliran fluida yang melalui saluran tersebut. Fenomena aliran melalui elbow yang menyebabkan pressure drop diantaranya adalah gesekan fluida dengan dinding saluran, separasi aliran dan secondary flow. Upaya yang dapat dilakukan untuk meminimalkan terjadinya pressure drop adalah dengan memberikan tambahan guide vane pada elbow. Penelitian ini dilakukan secara eksperimen. Model uji yang digunakan adalah octagonal elbow 90º dengan dua guide vane dan tanpa guide vane. Fluida yang mengalir adalah dengan asumsi udara incompressible, dan steady. Pada penelitian ini digunakan kecepatan free stream sebesar 5,5 m/s dan 11 m/s dengan Re sebesar 1,8 x 105 dan 3,6 x 105. Berdasarkan distribusi wall pressure coefficient (Cp), penambahan dua guide vane di dalam elbow pada Re = 1,8 x 105 mampu menurunkan ΔCp(inner-outer) sebesar 26,68% dan pressure drop (ΔCp(inlet-outlet)) sebesar 28,22%. Penambahan dua guide vane di dalam elbow pada Re = 3,6 x 105 dapat menurunkan ΔCp(innerouter) sebesar 16,28% dan pressure drop ΔCp(inlet-outlet) sebesar 21,05%. Berdasarkan distribusi profil kecepatan pada inlet dan outlet terlihat adanya aliran balik (backflow) pada bagian inner. Penambahan dua guide vane pada kedua Re dapat meminimalkan adanya backflow. Penambahan dua guide vane pada Re = 1,8 x 105 dan Re = 3,6 x 105 masing-masing dapat menurunkan tingkat intensitas turbulensi sebesar 25,2% dan 15,06%. "=============================================================================================" The use of elbow in a design of closed circuit wind tunnel, leads to the loss of pressure in the flow. It is caused by changes in the direction of fluid flow through the channel. The phenomena of flow through the elbow causing pressure drop include fluid friction with the walls of the channel, flow separation and secondary flow. Efforts should be made to minimize the pressure drop with additional guide vane at the elbow. This research was done experimentally. The test model is an octagonal 90º elbow with two guide vanes and without a guide vane. Fluid flow is air and is assumed incompressible and steady. In this experiment, the free stream velocities are 5,5 m / s and 11 m / s with Re of 1,8 x 105 and 3,6 x 105. Based on the distribution of wall pressure coefficient (Cp), the addition of two guide vanes in the elbow at Re = 1,8 x 105 can reduce ΔCp (inner-outer) of about 26,68% and the pressure drop (ΔCp (inlet-outlet)) of about 28,22%. The addition of two guide vane in the elbow at Re = 3,6 x 105 can reduce ΔCp (inner-outer) amounted to 16,28% and the pressure drop ΔCp (inlet-outlet) of about 21,05%. Based on the distribution of the velocity profile at the inlet and outlet, it is shown a presence of backflow (backflow) in the inner part. The addition of two guide vanes on both Re can minimize the backflow. The addition of two guide vanes at Re = 1,8 x 105 and Re = 3,6 x 105 can reduced the level of turbulence intensity of 25,2% and 15,06%.

Item Type: Thesis (Undergraduate)
Uncontrolled Keywords: octagonal elbow 90o, guide vane, pressure drop, backflow, secondary flow, windtunnel closed circuit,
Subjects: T Technology > TJ Mechanical engineering and machinery
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Users 13 not found.
Date Deposited: 04 Jan 2017 07:35
Last Modified: 26 Dec 2018 02:51
URI: https://repository.its.ac.id/id/eprint/1300

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