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All Journal AUSTENIT Jurnal Rekayasa Mesin Journal of Mechanical Engineering Science and Technology International Journal of Marine Engineering Innovation and Research
Rayhan, Fajri Ashfi
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Automotive Engineering Control & Systems Engineering Decision Sciences, Operations Research & Management Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Transportation

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Numerical Study on Resistance of Stepped Planing Hull Rayhan, Fajri Ashfi; Masrul, Andika; Khairullah Akbar, Arya; Anugerah Putra, Bima
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 7, No 2 (2023)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v7i22023p106

Abstract

A stepped planing hull, also known as a step hull, is a hull modification that reduces the wetted surface area. Although this type of hull has proven effective in several ships, it is still rarely used. The step hull possesses numerous advantages that make it ideal for activities involving small and fast boats. However, regrettably, its full potential remains untapped at present. The purpose of this study was to identify the effect of variations in the angle of the step hull on resistance or drag. The study utilized the CFD method, and three hull configuration models were used at each change in hull step angle of 180º, 210º, 240º, and 270º. Configurations 1 and 2 have similarities in terms of rear hull length (600 mm), hull height (20 mm for configuration 1 and 30 mm for configuration 2), and deadrise angle (15° for configuration 1 and 20° for configuration 2). Configuration 3 has similarities with an 800 mm rear hull, 20 mm hull height, and 15° deadrise angle. It was found that as the Froude number increases, the coefficient of total resistance decreases. Conversely, as the Froude number increases, the resulting resistance also increases. The configuration with the highest resistance value corresponds to the alteration from configuration 2 with a hull step of 180°, and that the alteration from configuration 2 with a hull step of 270° corresponds to the configuration with the lowest resistance value. This study concludes that deadrise angle and the height of the step hull are the main factors that require careful consideration when designing ships that use a step hull. Therefore, this research provides an understanding of the step hull and can serve as a basis for the development of the step hull.
PERANCANGAN KOMPOR BERBAHAN BAKAR OLI BEKAS UNTUK PENGERINGAN GARAM INDUSTRI Kurniawan, Harun; Septiana, Reski; Suryanegara, Lisman; Puspanegara, Dinar; Rayhan, Fajri Ashfi; Caniago, Deosa P
AUSTENIT Vol. 16 No. 1 (2024): AUSTENIT: April 2024
Publisher : Politeknik Negeri Sriwijaya, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53893/austenit.v16i1.8566

Abstract

Salt as a source of important minerals is much needed by society and industry. In the salt-making process, salt must go through a drying phase. Salt drying at the Badan Riset Nasional (BRIN)’s workshop that uses wood pellet as the fuel is considered not optimal because of waste in waiting and processing time. Other alternative fuels are needed to maximize the salt production process, one of which is using used lubricating oil. Utilizing used lubricating oil as fuel for the salt drying process requires the conversion of burner or stove. This research aims to design a stove fueled by used lubricant oil for drying industrial salt. French method is used to design the stove. The stove that has been built iwas compared with wood pellet stove in terms of waiting time to reach the desired salt drying temperature, fuel operational costs, and capacity of the salt produced. The ST-44 steel oil stove with a diameter of 17 cm and a height of 13 cm could reach the drying temperature 15 minutes faster than a wood pellet stove without the need of supervising the feeding process. Daily operational costs for fuel consumption using used lubricating oil were also more economical with 25% more dry salt produced than using a wood pellet stove.
Thermo-Environmental Performance Analysis of Cascade Refrigeration System on Cruise Ship Applications Natasya, Deva; Rayhan, Fajri Ashfi
International Journal of Marine Engineering Innovation and Research Vol. 11 No. 1 (2026)
Publisher : Department of Marine Engineering, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v11i1

Abstract

This study analyzes the thermo-environmental performance of cascade refrigeration systems applied to cruise ships to support energy efficiency improvement and emission reduction in accordance with MARPOL Annex VI regulations. Cruise ships have high energy demands, particularly in cooling systems that significantly contribute to overall energy consumption and environmental impact. This research aims to evaluate the effect of operating parameters and refrigerant selection on system performance using exergy efficiency, Ecological Coefficient of Performance (ECOP), and Total Equivalent Warming Impact (TEWI) as evaluation indicators. A thermodynamic model based on mass, energy, and exergy balance equations is applied, with simulations conducted under various operating temperatures and refrigerant combinations. The results indicate that increasing operating temperature from 275 K to 295 K reduces exergy efficiency and ECOP due to increased irreversibility, while TEWI rises significantly as a result of higher energy consumption. Hydrocarbon refrigerants such as R600a/R290 and R152a/R290 show the best performance in terms of both energy efficiency and environmental impact. In contrast, CO₂-based combinations tend to exhibit lower efficiency and higher environmental impact under certain conditions. Overall, selecting appropriate refrigerants and optimizing operating conditions are essential to achieve a balance between system efficiency and environmental sustainability in marine refrigeration systems.
Thermodynamic Performance Study of Cascade Cooling Systems on Cruise Ships with Mixed Working Fluids and Operating Parameters Rayhan, Fajri Ashfi; Natasya, Deva
Jurnal Rekayasa Mesin Vol. 21 No. 1 (2026): Volume 21, Nomor 1, April 2026
Publisher : Mechanical Engineering Department - Semarang State Polytechnic

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32497/jrm.v21i1.7412

Abstract

The cooling system is an important component on cruise ships to maintain engine operating temperatures and operational reliability. However, conventional cooling systems still have limitations in terms of energy efficiency and high thermodynamic losses. This study aims to analyze the performance of cascade cooling systems on cruise ships with variations in mixed working fluids, temperatures, pressures, and mass flow rates. The analysis was conducted using an energy and exergy approach to evaluate the Coefficient of Performance (COP), exergy efficiency, and exergy destruction. The study was conducted on a modified two-stage cascade cooling system. The working fluids analyzed include R22/R404A, R290/R404A, and R290/R600a. The results show that a decrease in mass flow rate in the high-temperature cycle increases the COP value, while an increase in temperature in Heat Exchanger Y increases exergy efficiency. The R22/R404A combination produced the highest exergy efficiency, while the hydrocarbon-based combination showed potential for COP improvement. This study demonstrates that optimizing operating parameters and selecting the appropriate working fluid can improve the energy efficiency of cascade refrigeration systems on cruise ships.
Co-Authors Anugerah Putra, Bima Caniago, Deosa P Khairullah Akbar, Arya Kurniawan, Harun Masrul, Andika Natasya, Deva Puspanegara, Dinar Septiana, Reski Suryanegara, Lisman