My Thesis Abstract: Ballads of Mechanics Power of the Screw Turbine

DESIGN AND EXPERIMENTAL STUDY OF THE INFLUENCE OF THE DIFFERENCE OF PITCHES AND SHAFT SLOPES TO MECHANICS PERFORMANCE OF 2-BLADES SCREW TURBINE MODEL IN LOW HEAD FLOW

BY
YUL HIZHAR
SUPERVISORS
1. Dr. Ir. Bambang Yulistianto
2. Ir. Suryo Darmo, M.T.

ABSTRACT

Screw turbine uses low head and high flow rate of water to generate rotation speed. Screw turbine has many advantages such as simple in construction and installation, low cost in operating and maintenance, and fish-friendly. The influencing parameters to mechanics performance of screw turbine are pitch distance and the shaft slope. The purposes of this research are to design 2-blades screw turbine model and to test the influence of pitch distance variation and shaft slope to mechanics performance in laboratory.

This research used experimental method which each of screw turbine model with pitch of 2Ro, 1.6Ro, and 1.2Ro were tested in variation of shaft slope of 25˚, 30˚, 35˚, 40˚, and 45˚. The water flow rate was 0.00728 m3/s. The data was acquisitioned at Hydraulics Laboratory Civil Diploma Universitas Gadjah Mada.

The result of testing without load showed that screw turbine model pitch of 2Ro had the higher rotation speed than pitch of 1.6Ro and 1.2Ro which the highest rotation speed was 255 rpm at shaft slope of 35˚. The result of testing with load showed that each turbine produced the highest rotation speed and output power at the shaft slope of 35º, meanwhile the highest efficiency was produced at the shaft slope of 25º. The result of research showed that generally screw turbine model pitch of 2Ro produced the higher mechanics performance (output power dan efficiency) than pitch of 1.6Ro and 1.2Ro. At the shaft slope of 25º, pitch 2Ro produced power 15.89 W and efficiency 73.08% (the highest), meanwhile at the shaft slope of 35º, pitch 2Ro produced power 18.51 W (the highest) and efficiency 66.16%. These efficiencies result difference were caused by the influence of the difference of hydropower (input power) at the variations of the shaft slopes.

Keywords: screw turbine model, pitch distance, shaft slope, rotation speed,

turbine power, turbine efficiency

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In Bahasa Indonesia, Abstract is called Intisari.

RANCANG BANGUN DAN STUDI EKSPERIMENTAL PENGARUH PERBEDAAN JARAK PITCH DAN KEMIRINGAN POROS TERHADAP KINERJA MEKANIK MODEL TURBIN ULIR 2 BLADE PADA ALIRAN HEAD RENDAH

OLEH
YUL HIZHAR
PEMBIMBING
1. Dr. Ir. Bambang Yulistianto
2. Ir. Suryo Darmo, M.T.

INTISARI

Turbin ulir merupakan salah satu jenis turbin yang memanfaatkan aliran air head H rendah dan debit Q tinggi untuk menghasilkan putaran. Turbin ulir memiliki beberapa kelebihan seperti kesederhanaan dalam konstruksi dan instalasi, biaya pengoperasian dan perawatan rendah, dan fish-friendly. Parameter-parameter yang mempengaruhi kinerja mekanik turbin ulir itu sendiri diantaranya perancangan jarak pitch dan kemiringan poros turbin. Penelitian ini bertujuan untuk merancang model turbin ulir 2-blade dan menguji pengaruh variasi pitch dan kemiringan poros terhadap kinerja mekanik yang dihasilkan dalam skala laboratorium.

Penelitian ini menggunakan metode eksperimental di mana masing-masing model turbin ulir dengan pitch 2Ro, 1,6Ro, dan 1,2Ro diuji pada variasi kemiringan sudut poros 25˚, 30˚, 35˚, 40˚, dan 45˚. Debit aliran yang digunakan yaitu 0,00728 m3/s. Pengumpulan data penelitian dilakukan di Laboratorium Hidrolika D3 Sipil Universitas Gadjah Mada.

Hasil pengujian tanpa beban menunjukkan bahwa model turbin ulir pitch 2Ro menghasilkan putaran yang lebih tinggi daripada ulir pitch 1,6Ro dan 1,2Ro yaitu 255 rpm pada kemiringan poros 35˚. Pada hasil pengujian berbeban, masing-masing model turbin ulir menghasilkan putaran dan daya tertinggi pada sudut kemiringan poros 35º, sementara efisiensi tertinggi dihasilkan pada kemiringan sudut poros 25º. Hasil pengujian menunjukkan bahwa secara umum model turbin ulir dengan pitch 2Ro menghasilkan kinerja mekanik berupa daya dan efisiensi lebih tinggi dibandingkan ulir pitch 1,6Ro dan 1,2Ro. Pada kemiringan sudut poros 25º, ulir pitch 2Ro menghasilkan daya sebesar 15,89 W dengan efisiensi 73,08% (tertinggi), sementara pada kemiringan sudut poros 35º, ulir pitch 2Ro menghasilkan daya sebesar 18,51 W (tertinggi) dengan efisiensi 66,16%. Perbedaan efisiensi ini diakibatkan oleh pengaruh perbedaan daya air (daya input) pada berbagai kemiringan sudut poros turbin.

Kata kunci: model turbin ulir, jarak pitch, kemiringan poros, putaran, daya turbin, efisiensi turbin

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