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%.
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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: | http://repository.its.ac.id/id/eprint/1300 |
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