Papers by Keyword: Flame Temperature

Abstract: In the production process of synthetic silica glass, SiCl₄ as precursor is imported in oxyhydrogen flame, SiO₂ particles generate and distribute with different states along the flame. The flame temperature and the distance above the burner are important factors to affect the particle diameters and morphologies. The 2D distribution of flame temperature was measured using sodium line-reversal method. The diameters and morphologies of SiO₂ particles were analyzed by transmission electron microscopy (TEM) at 50mm, 100mm, 200mm, and 300mm above the burner. The results show that the flame temperature ranges from 2130°C to 2320°C, and the average diameter of SiO₂ spherical particles increases from 50nm to 105nm as the distance increasing from 50mm to 200mm. The optimum deposition distance was discussed.

Abstract: To obtain evident ion current signals which reflect combustion condition in afterburner, areas of high ion concentration need to be identified. Using C₁₂H₂₃ as the fuel species, H₃O⁺, CHO⁺, COH⁺, O^- and OH^- as main ions, total ion concentration and temperature in flame behind a V-gutter flameholder are numerically simulated by realizable κ-ε turbulent model and non-premixed equilibrium chemistry model. Outlet section temperature is in good agreement with experimental data. The results show that distributions of ion concentration and temperature are consistent. There are two areas of high ion concentration: regions of the highest temperature in recirculation zone; regions close to upper and lower edges of flameholder. Peaks of each area appear near the injection holes.

Abstract: A numerical study on premixed combustion of CH₄ + CO₂ + Air in two dimensional is done. Parameters of inlet velocity and temperature of fuel and combustor geometry and size are considers the same but the CO₂ dilution rate changes. Results of this simulation shows that while the CO₂ dilution rate increases, flame temperature and velocity decrease. There is a limitation for increasing of CO₂ in the mixture. If amount of CO₂ in the mixture goes beyond the 47.7%, the fuel will lose its ability to be ignited and thus there will be no flame in the combustor. In addition, knowing the maximum temperature of flame may help to analyze the combustion process and choose suitable material in manufacturing the micro combustor.

Abstract: TiO2 nanoparticles were synthesized with using N2-diluted and O2-enriched coflow hydrogen diffusion flames. We investigated the effects of the flame temperature on the crystalline phases and particle characteristics of the TiO2 nanoparticles that were formed. For the higher temperature conditions, the maximum centerline temperatures that were measured were greater than approximately 1,600K, and TiO2 nanoparticles, which had spherical shapes with diameters of approximately 60nm, were synthesized. For the lower temperature conditions, the maximum centerline temperatures that were measured were less than approximately 1,600K, and the diameters of the nanoparticles that were formed had unclear boundaries that ranged from 35 to 50nm. From the XRD analyses, it was believed that the crystalline structures of the nanoparticles that were formed were divided into two types. For the higher temperature cases, the fractions of the TiO2 nanoparticles that were synthesized, which had anatase-phase crystalline structures, increased with the increase of the flame temperatures. On the contrary, for the lower temperature cases, the fraction of anatase-phase nanoparticles increased with the decrease of the flame temperatures.