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조한창,조길원,이용국,Cho, Han-Chang,Cho, Kil-Won,Lee, Yong-Kuk 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.10
Heat regenerator occupied by regenerative materials improves thermal efficiency of combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, was numerically analyzed to evaluate the heat transfer and pressure losses and to derive the design parameter for heat regenerator. It is confirmed that the computational results, such as air preheat temperature, exhausted gases outlet temperature, and pressure losses, agreed well with the experimental data. The thermal flow in heat regenerator varies with porosity, configuration of regenerator and diameter of regenerative particle. As the gas velocity increases with decreasing the cross-sectional area of the regenerator, the heat transfer between gas and particle enhances and pressure losses decrease. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled lower with the increase of pressure losses. Assuming a given exhaust gases temperature at the regenerator outlet, the regenerator need to be linearly lengthened with inlet Reynolds number of exhaust gases, which is defined as a regenerator design parameter.
맥동연소기술이 접목된 복사관 버너에서의 NO<sub>X</sub> 배출 특성
조한창,조길원,김후중,Cho, Han-Chang,Cho, Kil-Won,Kim, Hoo-Joong 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.2
An experimental study was carried out in a small-scale test furnace to investigate the performance, such as $NO_X$ emission, enhancement of heat transfer, uniformity of temperature, and etc, of oscillating combustion applied in radiant tube burner system. A premixed type burner and a cyclic oscillating control valve were designed and used. The fuel, used commercial LPG in this study, was only oscillated using the cyclic oscillating control valve. As oscillating combustion was applied in radiant tube burner system, it is found that $NO_X$ emission, compared to no oscillation, could be reduced by 38% at $90{\sim}120rpm\;(1.5{\sim}2.0Hz)$. However, as oscillating frequency was increased, effect of abatement of $NO_X$ emission is gradually reduced. From the measurement of furnace heating time from $100^{\circ}C$ to $720^{\circ}C$, heat transfer is increased by 11.5% at the oscillation of 120rpm. Temperature distribution of radiant tube surface is more uniform at oscillation of 120rpm with decrease of the peak temperature and increase of low temperature. From these results, it is confirmed that oscillating combustion is useful in radiant tube burner system.
조한창(Han Chang Cho),조길원(Kil Won Cho) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
An experimental study was carried out in a real scale test furnace to investigate the performance, such as NOx emission, enhancement of heat transfer, uniformity of temperature, and etc, of oscillating combustion applied in radiant tube burner system. A oscillating controller with solenoid valve were designed and used. Two burners used in steel industry were tested in this study. The fuel, used commercial LPG in this study, was only oscillated using the oscillating controller with a solenoid valve. As oscillating combustion was applied in radiant tube burner system, it is found that NOx emission, compared to no oscillation, could be reduced by 20~30% at 2.5㎐ without CO emission. However, as oscillating frequency was increased, effect of abatement of NOx emission is gradually reduced. From the measurement of furnace heating time from 100℃ to 900℃, heat transfer is increased by 4.0% at the oscillation of 2㎐. Temperature distribution of radiant tube surface is more uniform at oscillation of 2Hz with decrease of the peak temperature and increase of low temperature. From these results, it is confirmed that oscillating combustion is useful in radiant tube burner system.