Studi Numerik Penanganan Keausan Shaft Turbin PLTA Tipe Kaplan Vertikal : Studi Kasus PLTA Wonogiri Unit 2

Tarihoran, Marudut (2026) Studi Numerik Penanganan Keausan Shaft Turbin PLTA Tipe Kaplan Vertikal : Studi Kasus PLTA Wonogiri Unit 2. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pada PLTA Wonogiri Unit 2, journal shaft turbin Kaplan vertikal mengalami keausan tidak merata pada sekitar 50% keliling dengan kedalaman maksimum sekitar 5 mm. Permasalahan utama penelitian ini adalah menentukan alternatif penanganan yang mampu mengembalikan karakteristiknya mendekati kondisi normal. Penelitian dilakukan menggunakan metode Finite Element Analysis pada ANSYS Workbench melalui static structural analysis dan modal analysis. Empat kondisi dibandingkan, yaitu shaft normal, shaft aus tidak merata, shaft yang direkondisi menggunakan Belzona 1111, serta shaft yang dibubut secara konsentris dan dipasang shock sleeve berbahan stainless steel SS410. Seluruh model menggunakan geometri assembly, kondisi tumpuan, strategi meshing, parameter operasi, dan pengaturan solver yang konsisten. Hasil simulasi menunjukkan bahwa keausan meningkatkan deformasi maksimum dari 0,0070138 mm menjadi 0,1406 mm atau sebesar 1.904,62%, serta menurunkan frekuensi alami mode pertama dari sekitar 33,94 Hz menjadi sekitar 9,23 Hz. Rekondisi Belzona menurunkan deformasi menjadi 0,093862 mm atau 33,24% terhadap kondisi aus, tetapi masih menunjukkan ketidaksimetrian lokal. Shock sleeve SS410 menghasilkan deformasi 0,0070086 mm, menurun 95,02% dari kondisi aus, dengan selisih hanya 0,074% terhadap shaft normal. Frekuensi alami dan pola mode shape juga paling mendekati kondisi normal. Pembubutan konsentris dan pemasangan shock sleeve SS410 merupakan alternatif terbaik karena menghasilkan respons struktural dan dinamis paling stabil serta kecenderungan eksentrisitas paling rendah.
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At Wonogiri Hydropower Plant Unit 2, the journal section of the vertical Kaplan turbine shaft experienced non-uniform wear over approximately 50% of its circumference, with a maximum wear depth of approximately 5 mm. The primary objective of this study was to determine the most effective repair alternative for restoring the shaft characteristics to a condition comparable to the normal state. The study employed the Finite Element Analysis method using ANSYS Workbench, incorporating static structural and modal analyses. Four shaft conditions were evaluated: the normal shaft, the non-uniformly worn shaft, the shaft reconditioned using Belzona 1111, and the shaft subjected to concentric machining followed by the installation of an SS410 stainless-steel shock sleeve. All models were analysed using consistent assembly geometries, boundary conditions, meshing strategies, operating parameters, and solver settings.The simulation results indicated that shaft wear increased the maximum deformation from 0.0070138 mm to 0.1406 mm, corresponding to an increase of 1,904.62%, while reducing the first-mode natural frequency from approximately 33.94 Hz to approximately 9.23 Hz. Reconditioning with Belzona 1111 reduced the maximum deformation to 0.093862 mm, representing a 33.24% reduction relative to the worn condition; however, local asymmetry remained evident. The SS410 shock sleeve configuration resulted in a maximum deformation of 0.0070086 mm, corresponding to a 95.02% reduction relative to the worn condition and a difference of only 0.074% compared with the normal shaft. Its natural frequencies and mode-shape characteristics also showed the closest agreement with those of the normal condition. Therefore, concentric machining followed by the installation of an SS410 shock sleeve was identified as the most effective repair alternative, as it provided the most stable structural and dynamic responses and the lowest tendency toward eccentricity.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	keausan shaft, turbin Kaplan vertikal, modal analysis, deformasi radial, shock sleeve.shaft wear, vertical Kaplan turbine, modal analysis, radial deformation, shock sleeve.
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ164 Power plants--Design and construction
Divisions:	Faculty of Industrial Technology > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Marudut Tarihoran
Date Deposited:	05 Aug 2026 05:39
Last Modified:	05 Aug 2026 05:39
URI:	http://repository.its.ac.id/id/eprint/144040

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