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Experimental Analysis of Gas Split Injection Effect on Dual-Fuel Engine Performance Semin; Yudha Prasetiyo; Beny Cahyono; Frengki Mohamad Felayati
International Journal of Marine Engineering Innovation and Research Vol. 6 No. 2 (2021)
Publisher : Department of Marine Engineering, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v6i2.5845

Abstract

The application of a dual-fuel engine has massively been used as the main engine. However, in dual-fuel engine operations, problems occur in low-load operations. The combustion quality with unstable combustion conditions and relatively low thermal efficiency. In this research, a gas split injection strategy was implemented on the dual-fuel engine. The purpose of this research is to compare the performance of the engine between dual-fuel operations using gas split injection strategy and single injection. Furthermore, split injection is a fuel injection system by dividing the injection into several injection stages with a certain mass and period. This injection system was applied on a dual-fuel engine system, which was previously a modification of the conventional diesel Yanmar TF 85 MH. The variation in this study is the injection split ratio (ISR) 75-25, variations in injection time, and variations in load with specified engine speed at 2000 RPM. The results obtained in this study are the best variations found in ISR 75-25 gas split injection with injection distance at 260°bTDC & 244°bTDC. Due to the injection distance, a significant difference occurred in all parameters tested between single injection and split injection. The significance of the difference in power, torque, BMEP, SFOC, and the thermal efficiency only occurs at 100% load, which is 4.3%; 4.2%; 4.2%; 16%; 18.3%.
Cavitation Analysis of Kaplan-Series Propeller: Effect of Pitch Ratio and nProp using CFD Mohammad Danil Arifin; Frengki Mohamad Felayati
International Journal of Marine Engineering Innovation and Research Vol. 6 No. 2 (2021)
Publisher : Department of Marine Engineering, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v6i2.5847

Abstract

Cavitation is defined as a phenomenon or action of the traveling bubbles that pass through the hydrofoil in which the reduction of pressure below the liquid’s vapor pressure leads to the formation of small vapor bubbles (or cavities) caused by the dynamic pressure of the propeller blades. It caused some effects on the propeller of the ship i.e. it can greatly reduce a ship’s propelling efficiency, damaged propeller material or blade erosion, vibration, and disturbance noises. Cavitation can be minimized by proper attention regarding the design of the propellers and variation of propeller variables parameters. For that reason, this research conducts a cavitation analysis on the Kaplan-Series of the CPP by varying P/Db=0.4, P/Db=0.6, and P/Db=0.8; also the rotational speed of the propeller (nProp) i.e. 125 rpm, 175 rpm and, 225 rpm. The numerical analysis was made based on the Computational Fluid Dynamic Method (CFD) to calculate the pressure ratio (deltaP) and percentages of the cavitation area (Rs) due to a configuration of the propellers parameter. The simulation consists of the 3 steps; pre-processor, solver manager, and post-processor. The result shows that the value of the pressure ratio increased significantly at the higher P/Db and nProp. Also, the variation of P/Db and nProp has a significant effect on the development of Rs (%) at the higher P/Db and nProp.
Numerical Study of B-Screw Ship Propeller Performance: Effect of Tubercle Leading Edge Mohammad Danil Arifin; Frengki Mohamad Felayati
International Journal of Marine Engineering Innovation and Research Vol. 6 No. 1 (2021)
Publisher : Department of Marine Engineering, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25481479.v6i1.5853

Abstract

Various attempts to modify the ship's propeller have been made to improve performance as a propulsion component. This paper analyzes the effect of modification of the B-Series propeller by adopting a whale fin shape (Humpback Whale). Also, it analyzes the flow in the propeller before (standard) and after modification. Modifications are made to the leading edge, which is called the tubercle leading edge (TLE). It adds and subtracts sections with a wavelength of 0.2R and amplitude of 2.5% of the chord section length in the propeller leading edge. The numerical study is used using CFD on different J values (0.2, 0.4, and 0.6). It was found that the modification of TLE has a less significant effect on performance. Instead, it decreased at a low J value (0.2). Meanwhile, the largest decrease was at a high J value (0.6), namely up to 10.4% for thrust, 4.3% for torque, and 6.4% for efficiency. Whereas at J=0.4, the torque increases only 0.4%, and the torque and thrust decrease, although less significant. The flow analysis indicates that the shape of the TLE provides a decrease in pressure. However, on the positive side, this modification provides a reduction in noise on the propeller surface.