Sheila Tobing
Energy Systems Engineering Masters Study Program, Faculty of Engineering, University of Indonesia, Jl UI Depok Campus, Depok, West Java, 16424

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Evaluation of Kinetic Mechanism for Modelling Dimethyl Ether Jet Diffusion Flame Ahmad Syihan Auzani; Sheila Tobing; Ridhwan Sunandar; Riesta Anggarani; Cahyo Setyo Wibowo; Dedi Sutarma
Indonesian Journal of Computing, Engineering, and Design (IJoCED) Vol. 4 No. 2 (2022): IJoCED
Publisher : Faculty of Engineering and Technology, Sampoerna University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35806/ijoced.v4i2.298

Abstract

Many countries use liquefied petroleum gas (LPG) for various purposes, such as cooking and heating. As the population and the need for energy grow, demand for LPG steadily increases. This situation causes the rise in LPG imports for countries with an insufficient local supply, including Indonesia. To overcome this problem, the Indonesian Government plans to substitute LPG fuel with dimethyl ether (DME). However, stoves and household burners widely used in Indonesia are designed for LPG. Thus it is necessary to study the fuel flexibility of the burners. Many experimental studies on the substitution of LPG with DME are reported in the literature, but few models have been developed to simulate it. This paper aims to evaluate the performance of reaction mechanisms developed to model DME diffusion flames with various burner temperatures ranging from 300 to 1500 K. It was found that existing models could simulate the chemical structure of the flame but could not predict the formation of enthalpy of combustion reactions.
Declining Cogging Torque Technique of an Integral Slot Number for Permanent Magnet Machines Herlina Herlina; Tajuddin Nur; Maria Angela Kartawidjaja; Linda Wijayanti; Kumala Indriati; Sheila Tobing
Jurnal Rekayasa Elektrika Vol 19, No 4 (2023)
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17529/jre.v19i4.30028

Abstract

The existence of cogging torque in electric equipment has been considered undesirable. This kind of friction in the air-gap impacts the alignment of flux and the stator slots, resulting in the observed outcome. Consequently, the imposition of restrictions on the rotation of the rotor is employed to generate electrical energy. This research endeavor primarily aims to mitigate the cogging torque of electrical machinery. The current utilization involves employing a total of 3 permanent magnet synchronous machines, often known as inset PMMs, which possess a slot count of 24 and a pole count of 8. The employed technique involves the integration of an optimal pole arc method in conjunction with the implementation of slots cut into the magnet's edge. The machine model under investigation has two fundamental variants, namely Models 1 and 2. These models are equipped with 1one-step slotted (OSS) and 2two-step slotted (TSS) edges on each magnet, in addition to pole arc optimization. The simulation was conducted using the Finite Element Method Magnetics (FEMM) 4.2 software together with LUA scripts, with a focus on rotor rotation ranges of 1 degree. Model 2 exhibited a decrease in cogging torque of 0.01 Nm, whereas Model 1 demonstrated a reduction of 0.015 Nm, and the basic model had a decrease of 0.02 Nm. When implementing a dual-layered cutting edge on a magnet and attempting to optimize its pole arc, it is imperative to consider that the cogging torque's peak magnitude becomes substantially diminished or entirely eliminated.