Modelling And CFD Analysis of Nozzle Diffuser Cross Flow Marine Turbine

Prasetya, Arya Rheytra (2026) Modelling And CFD Analysis of Nozzle Diffuser Cross Flow Marine Turbine. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kapal nelayan tradisional umumnya masih memakai mesin berbahan bakar fosil, yang menyebabkan biaya operasional tinggi dan menambah emisi. Penelitian ini memodelkan dan menganalisis secara numerik nozzle diffuser cross flow marine turbine sebagai sumber energi alternatif untuk kapal nelayan tipe jukung, dengan fokus pada torsi yang dihasilkan turbin. Saluran nozzle-diffuser dirancang dengan geometri tetap menggunakan Software 3D Modelling, sedangkan rotor turbin dimodelkan di secara 3D dalam lima konfigurasi berdasarkan jumlah blade: 14, 16, 20, dan 22 blade, ditambah satu varian hollow hub pada 16 blade. Setiap konfigurasi disimulasikan dengan metode CFD di ANSYS Fluent menggunakan model turbulensi k-ω SST dan pendekatan 6-DOF untuk gerak rotor, pada kecepatan aliran masuk yang mewakili arus laut 5, 7,5, dan 10 knot. Dari gaya yang bekerja pada blade, dihitung RPM, torsi poros, dan daya mekanik, yang kemudian divalidasi terhadap data eksperimen. Hasil menunjukkan turbin 20 dan 22 blade gagal berputar, menghasilkan RPM, torsi, dan daya yang mendekati nol pada semua kecepatan uji, sehingga tidak layak digunakan. Turbin 16 blade dengan solid hub tampil paling baik secara keseluruhan, mencapai efisiensi puncak 11,72% dan daya mekanik hingga 18,4 W pada 10 knot tertinggi di antara semua konfigurasi. Turbin 14 blade tampil moderat, sementara varian hollow hub menurunkan performa di semua aspek. Hasil ini menegaskan konfigurasi 16 blade solid hub sebagai desain terbaik dari semua variasi bilah.
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Traditional fishing boats mostly still use engines that run on fossil fuel, causing high operating costs and emissions. This study models and numerically analyzes a nozzle-diffuser cross flow marine turbine as an alternative energy source for jukung-type fishing boats, focusing on the torque produced by the turbine. The nozzle-diffuser duct was designed with a fixed geometry using 3D Modelling Sofware, while the turbine rotor was modeled in 3D in five configurations based on blade number: 14, 16, 20, and 22 blades, plus a 16-blade hollow-hub variant. Each configuration was simulated using the CFD method in ANSYS Fluent with the k-ω SST turbulence model and a 6-DOF approach for rotor motion, at inlet velocities representing 5, 7.5, and 10 knot ocean currents. From the resulting forces on the blades, RPM, shaft torque, and mechanical power were calculated and validated against experimental data. Results show that the 20-blade and 22-blade turbines failed to rotate, producing near-zero RPM, torque, and power at all tested velocities, making them unviable designs. The 16-blade solid-hub turbine performed best overall, reaching a peak efficiency of 11.72% and mechanical power up to 18.4 W at 10 knots the highest among all configurations. The 14 blade turbine performed moderately, while the hollow-hub variant reduced performance in all aspects. These results confirm the 16-blade solid-hub design as the most viable configuration for each turbine blade variation.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Computational Fluid Dynamics (CFD); crossflow; hydrokinetik; Nozzle diffuser; turbin Computational Fluid Dynamics (CFD); crossflow; Hydrokinetic; Nozzle diffuser; Turbine;
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM740 Marine turbines
Divisions:	Faculty of Marine Technology (MARTECH) > Marine Engineering > 36202-(S1) Undergraduate Thesis
Depositing User:	Arya Rheytra Prasetya
Date Deposited:	04 Aug 2026 07:54
Last Modified:	04 Aug 2026 07:55
URI:	http://repository.its.ac.id/id/eprint/143302

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