Studi Eksperimen Aliran Melalui Square Duct dan Single Guide Vane Elbow 90° terhadap Cylinder Disturbance Body dengan Pengaruh Variasi Gap

Hisyam, Ahmad (2018) Studi Eksperimen Aliran Melalui Square Duct dan Single Guide Vane Elbow 90° terhadap Cylinder Disturbance Body dengan Pengaruh Variasi Gap. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian yang dilakukan oleh Shiming Deng & John Burnett tahun 2002 tentang rata-rata penggunaan energi di 16 hotel besar di Hongkong menunjukkan konsumsi energi pada gedung persentase 45% untuk sistem tata udara, 31% untuk non-electrical, 17% untuk sistem tata cahaya, dan 7% untuk sistem transportasi gedung. Dari data tersebut didapatkan presentase konsumsi energi terbesar ialah untuk pengkondisian tata udara (air conditioning). Instalasi square duct memiliki kelebihan mudah dipasang dan hemat ruang. Maka dari itu dengan mengurangi kerugian pada instalasi saluran udara, diyakini dapat mengurangi separation loss dan secondary flow serta meningkatkan efisiensi secara keseluruhan. Salah satunya dengan merekayasa fitting perpipaan elbow 90° dengan penambahan single guide vane. Penelitian dilakukan secara eksperimen dengan saluran berpenampang bujur sangkar (square duct) dengan Dh = 125 mm yang terdiri dari : upstream duct (straight duct) dengan panjang 7Dh, Cylinder Disturbance Body (CDB) dengan d = 6 mm, square elbow 90° dengan curvative ratio (R/Dh)=1,5 dan downstream duct (straight duct) dengan panjang 15Dh, serta centrifugal fan. Pengukuran dalam penelitian ini menggunakan pitot static tube, inclined manometer, dan pressure transducer. Pengujian dilakukan dengan variasi gap (g/Dh= 0,1 ;0,2 ;0,3 ;0,4 dan 0,5) dan l/Dh=0,5 yang diletakkan pada upstream duct. Untuk mendapatkan nilai pressure drop dan coefficient loss elbow 90° digunakan 〖Re〗_Dh 1,59 x 104 sampai 1,59x105 (kecepatan udara 2 m/s sampai 20 m/s dengan kenaikan tiap 2 m/s), untuk coefficient pressure pada elbow 90º digunakan kecepatan 2 m/s, 12 m/s,dan 20 m/s dengan 〖Re〗_Dh 3,17x104; 9,52x104; dan 1,59x105. Sedangkan untuk mendapatkan profil kecepatan digunakan 〖Re〗_Dh sebesar 9,52 x 104 pada jarak (x/Dh)=2,4,6,10,dan 14 sepanjang downstream duct. Hasil penelitian ini diperoleh bahwa penempatan CDB cukup efektif untuk mereduksi nilai pressure drop dengan variasi gap g=0,1Dh, dimana mampu mereduksi sebesar 0,02% terhadap rasio pressure drop dengan cylinder disturbance body dan pressure drop tanpa disturbance body (∆pDB/∆pD0). Lalu pada hasil koefisien losses (K) elbow 90º juga didapatkan pada variasi CDB g=0,1Dh dibandingkan tanpa bodi pengganggu, yang mampu mereduksi dengan nilai rata-rata koefisien losses (K) elbow 90º sebesar 0,218. Penurunan nilai selisih Pressure Coefficient pada sisi outer wall dan sisi inner wall (ΔCp) paling efektif pada variasi jarak g=0,1Dh sebesar 0.66, sedangkan nilai ΔCp tanpa CDB sebesar 0.70, namun pada variasi g=0,3Dh nilai ΔCp mengalami kenaikan dibandingkan nilai ΔCp tanpa CDB sebesar 0,75. Pada profil kecepatan bidang horizontal dan vertical pada section 2;4; dan 6 menggambarkan dengan penambahan CDB memiliki profil kecepatan yang berbeda dibandingkan tanpa CDB, sementara pada section 10 dan 14 secara keseluruhan variasi memiliki profil kecepatan yang mirip. Dapat ditarik kesimpulan bahwa masih terdapat backflow atau perlambatan aliran yang ditimbulkan dari single guide vane maupun separasi aliran pada sisi inner wall dan centerline. ======================================================================================================== Research conducted by Shiming Deng & John Burnett 2002 about average energy use in 16 major hotels in Hong Kong shows the energy consumption in the building with the 45 % for system of air , 31 % to non-electrical , 17 % to a system the lighting , and 7 % to transportation system building. From the data obtained the percentage largest energy consumption is to conditioning of air duct system. Installation square duct having an excess easy fitted and save space. Therefore by reducing losses on the installation of air ducts, it is believed can reduce separation loss and secondary flow and than improve overall efficiency. One of them is with modification the fittings pipes elbow 90° by the addition of a single guide vane This research is carried out by experiments with models of rectilinear shaped channel square duct with Dh=125 mm consisting of upstream duct (straight duct) with 7Dh length, Cylinder Disturbance Body (CDB) with d=6 mm, square elbow 90 ° with curvative ratio (R/Dh) = 1,5 and the addition of Single Guide Vane, downstream duct (straight duct) with 15Dh length, and centrifugal fan. Measurements in this study using pitot static tube, inclined manometer, and a pressure transducer. The experiment conducted with the variation of gap (g/Dh = 0.1; 0.2; 0.3; 0.4 and 0.5) and l=0.5Dh was placed on the upstream duct. To get the value of pressure drop and coefficient loss elbow 90° used ReDh 1,59 x 104 to 1,59 x 105 (air velocity 2 m/s to 20 m/s with speed increase every 2 m/s), for obtain cofficient pressure at 90º elbow used air velocity 4 m/s, 12 m/s and 20 m/s with ReDh 3,17x104; 9.52x104 and 1,59x105, while to get the velocity profile along the upstream duct and downstream duct used ReDh of 9,52x104 with distance (x/Dh)=2,4,6,10, and 14 along the downstream duct. The results of this research were obtained that the placement of the CDB is effective for reducing the value of pressure drop with variations of gap g=0,1Dh where able to decrease for 0.02% towards pressure drop ratio with the cylinder body disturbance and pressure drop without disturbance body (∆pDB/∆pD0). Then, in the results of losses coefficient (K) elbow 90 º is also obtained on a variation of the CDB g=0,1Dh compared without disturbance body, has an average value of losses coefficient (K) 90º elbow of 0.218. Decreasing of the difference value coefficient pressure on side of outer and inner wall (ΔCp) is most effective on a variation g=0,1Dh amounted to 0,66, while value ΔCp without the CDB is 0.70, but on variations g =0,3Dh ΔCp values increase compared without the CDB with value 0,75. On the velocity profile horizontal and vertical section 2; 4; and 6 can be illustrated with the addition of the CDB has a different velocity profiles are compared without the CDB, while section 10 and 14 overall variations have similar velocity profile. Can be concluded there are still have a backflow or slowing flowcaused from single guide vane or separation flow on the side of inner wall and the centerline.

Item Type: Thesis (Undergraduate)
Additional Information: RSM 532 His a-1 3100018077011
Uncontrolled Keywords: Cylinder Disturbance Body, Pressure Drop, Square Duct, Elbow 90o,Single Guide Vane
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA357 Computational fluid dynamics. Fluid Mechanics
T Technology > TJ Mechanical engineering and machinery
T Technology > TJ Mechanical engineering and machinery > TJ935 Pipe--Fluid dynamics.
Divisions: Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User: Ahmad Hisyam
Date Deposited: 25 Dec 2020 06:12
Last Modified: 25 Dec 2020 06:12
URI: https://repository.its.ac.id/id/eprint/56278

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