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All Journal INOVTEK POLBENG Jurnal Teknologi Terapan Journal of Mechanical Engineering, Science, and Innovation
Bachtiar Bachtiar
Politeknik Perkapalan Negeri Surabaya
Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Mechanical Engineering

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STUDI NUMERIK PENGARUH PERUBAHAN OBSTACLE SEGITIGA TERPASANG DI DEPAN RETURNING BLADE TERHADAP KINERJA DARRIEUS WIND TURBINE TIPE NACA 0015 Bachtiar Bachtiar; Nopem Ariwiyono
INOVTEK POLBENG Vol 9, No 1 (2019): INOVTEK VOL.9 NO 1 - 2019
Publisher : POLITEKNIK NEGERI BENGKALIS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (532.465 KB) | DOI: 10.35314/ip.v9i1.905

Abstract

Angin merupakan salah satu sumber renewable terbaik dengan ketersediaan yang sangat melimpah. Penelitian ini menambahkan obstacle segitiga sama sisi diletakkan di depan sisi returning blade pada turbin Darrieus. Obstacle segitiga di depan returning blade diduga akan menurunkan drag sisi sudu returning blade dengan konsekuensi akan menurunkan torsi negatif dan akibatnya akan meningkatkan torsi total dan daya turbin Darrieus. Penelitian ini menggunakan metode numerik dengan menggunakan foil NACA 0015, panjang chord 20 cm, diameter Darrieus berukuran 800 cm, kecepatan angin 3 m/s. Penelitian dilakukan dengan memvariasikan jarak obstacle y = 20 cm, 40 cm dan 60 cm. Simulasi numerik menggunakan moving mesh dengan jenis turbulence model Reliazible k-epsilon (RKE). Simulasi numerik melakukan ploting terhadap koefisien torsi (Cm) dan koefisien daya (Cp) Hasil dari penelitian ini menunjukkan bahwa kinerja terbaik pada y = 60 cm dengan maksimum koefisien daya sebesar 0,377 pada TSR 1,535 atu meningkat sekitar 7,08%.
ANALISIS PENGARUH VARIASI TEKANAN GAS DAN PERSENTASE KETEBALAN LAPISAN BOUNDING DAN COATING PADA PROSES REBUILD-UP MATERIAL BAJA AISI 1045 DENGAN METODE ARC SPRAY TERHADAP TINGKAT KEREKATAN ANTAR LAPISAN Fathani Adhitya Mamang; Bachtiar Bachtiar; Imam Khoirul Rohmat; Adri Fato
Jurnal Teknologi Terapan Vol 9, No 2 (2023): Jurnal Teknologi Terapan
Publisher : P3M Politeknik Negeri Indramayu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31884/jtt.v9i2.463

Abstract

Each engine component has the durability that can decrease and wear due to continuous friction. The thermal spray method is an alternative that is used. The type of thermal spray that is found in the industry is Arc Spray. However, the peeling of the coating metal with the substrate is one of the problems. In this study, the variables that have contributed to the peeling of the coating layer were taken. The variables compared are the total thickness of the bounding and coating layers of 1 mm with a percentage of 50% : 50% and 30% : 70%. Another variation is gas pressure of 2 Bar, 3 Bar and 4 Bar in rebuild-up process of AISI 1045. Specimens with thickness percentage of 30% : 70% have significant difference in tensile strength value compared to the thickness percentage of 50% : 50% with an average difference of 5.02 MPa; 4.8975 MPa and 3.29 MPa in specimens with a gas pressure of 2 bar; 3 bars; 4 bars. The influences of thickness of bound and top coat have percentage effect 21.12% on each layer. As the gas pressure increases, the bonding value is higher because the higher gas, the smaller porosity which is proved by microstructural tests.
Analysis of Tube Expansion Percentage on Microstructure and Hardness of 316L Stainless Steel Tube-to-Tubesheet Connections with GTAW Process Moh. Syaiful Amri; Bachtiar Bachtiar; Moh. Miftachul Munir; Mukhlis Mukhlis; Muhammad Ari; Ilham Kurniawan
Journal of Mechanical Engineering, Science, and Innovation Vol 5, No 2 (2025): (October)
Publisher : Institut Teknologi Adhi Tama Surabaya, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.jmesi.2025.v5i2.8161

Abstract

This study analyzes the effect of varying tube expansion percentages on the mechanical properties, microstructure, and hardness of SA-213 TP316L tubes joined to SA-240 TP316L tubesheets in a shell-and-tube type heat exchanger. The tube expansion process was carried out using a roller expander with three expansion levels: 4%, 8%, and 12%, followed by Gas Tungsten Arc Welding (GTAW) at 150 A. Microstructural observations revealed that all joint zones were dominated by austenite with small amounts of delta ferrite, where increasing expansion percentages induced significant changes in the expand area: slight deformation at 4%, grain elongation at 8%, and pronounced grain distortion at 12%. Macrostructural observations showed perfect fusion between the tube and tubesheet for all variations, with no macro defects such as lack of fusion or porosity. Vickers hardness testing indicated the highest values in the expand area for all variations, with a maximum of 377 Kgf/mm², exceeding the standard limit of 250 Kgf/mm² for stainless steel. The hardness of the base metal was around 180 Kgf/mm², while the weld metal ranged from 220–230 Kgf/mm² due to delta ferrite formation. The increase in hardness in the expand area was attributed to cold working effects, indicating that post-tube expansion heat treatment is necessary to reduce residual stresses and restore the optimal mechanical properties of the material.
Co-Authors Adri Fato Fathani Adhitya Mamang Ilham Kurniawan Imam Khoirul Rohmat Moh. Miftachul Munir Moh. Syaiful Amri Muhammad Ari Mukhlis Mukhlis Nopem Ariwiyono, Bachtiar