การออกแบบเชิงตัวเลขของเตาเผาทรงกระบอกสำหรับการใช้งานกังหันแก๊สขนาดเล็ก

บทคัดย่อ

Nowadays, electrical energy is important in daily life and industry. The micro gas turbine is one type of technology used in generating power, with a small scale and reliably distributed power system. Advantages of the micro gas turbine are that it is cost effective, reliable and low maintenance. Fuels for producing electrical energy via the micro gas turbine are the subject of this study because the combustion efficiency of the optimal cylindrical combustor will change as it is used with different fuels. Therefore, the re-designed configuration of the combustor is necessary for improving the efficiency of the micro gas turbine. A computational design is implemented because of the accuracy in calculation and ease of modelling. This research mainly focuses on the efficiency of the combustor in the micro gas turbine system as the main fuel supplied is changed from LPG to natural gas (methane). The geometry of the cylindrical combustor was constructed by SolidWorks and then numerically solved by Fluent. The cylindrical combustor has a 50 mm flame holder, 600 mm chamber height, and four holes of 6, 8, 10 mm for the dead zone, combustion zone and dilution zone, respectively. Different fuels were used in simulations with a non-premix combustion model, consisting of the standard k-e model for turbulent flow, energy equation, continuity equation and P-1 radiation model. All of the equations were solved by a finite volume method. The results were validated with the experimental data of (Enagi et al., 2017) and show that both cases provide similar temperature contours.    The average temperatures at the outlet of LPG and methane fuels were 1318 K and 1312 K, respectively. In contrast, the mass fraction distributions of the product gases, i.e. H₂O and CO₂, in both cases were different. This resulted in different efficiencies of combustion, in which the combustor with methane was shown to provide higher combustion efficiency.