Numerical study was performed to evaluate the characteristics of combined heat transfer of radiation, conduction and convection in indirect near infrared ray （N/R） heating chamber. The effects of important design pa...Numerical study was performed to evaluate the characteristics of combined heat transfer of radiation, conduction and convection in indirect near infrared ray （N/R） heating chamber. The effects of important design parameters such as the shape of heat absorbing cylinder and heat releasing fin on the pressure drop and heat transfer coefficient were analyzed with different Reynolds numbers. The Reynolds numbers were varied from 103 to 3x106, which was defined based on the hydraulic diameter of the heat absorbing cylinder. Analyses were performed to obtain the inner and outer flow and the temperature distributions in the heat absorbing cylinder and the rates of radiation heat transfer and convection heat transfer. As the Reynolds number increases, the convection heat transfer rate is increased while the radiation heat transfer rate is decreased. The average convection heat transfer rate follows a power rule of the Reynolds number. Addition of three-dimensional heat releasing fin to the outside of the heat absorbing cylinder enhances the convection heat transfer.展开更多
The present study deals with analytical investigation of temperature of a single burning iron particle.Three mathematical methods including AGM(Akbari-Ganji’s method),CM(Collocation method)and GM(Galerkin Method)are ...The present study deals with analytical investigation of temperature of a single burning iron particle.Three mathematical methods including AGM(Akbari-Ganji’s method),CM(Collocation method)and GM(Galerkin Method)are applied to solving non-linear differential governing equation and effectiveness of these methods is examined as well.For further investigation,forth order Runge-Kutta approach,a numerical method,is used to validate the obtained analytical results.In the present study,the developed mathematical model takes into account the effects of thermal radiation,convective heat transfer and particle density variations during combustion process.Due to particles’small size and high thermal conductivity,the system is assumed to be lumped in which the particle temperature does not change within the body and all of its regions are at the same temperature.The temperature distributions obtained by analytical methods have satisfactory agreement with numerical outputs.Finally,the results indicate that AGM is a more appropriate method than GM and CM due to its lower mean relative error and less run time.展开更多
The effect of pressure on combustion and heat transfer is analyzed. The research is based on the basic combustion and heat transfer theorem. A correction for the heat calculation method for pressurized furnace is made...The effect of pressure on combustion and heat transfer is analyzed. The research is based on the basic combustion and heat transfer theorem. A correction for the heat calculation method for pressurized furnace is made on the basis of the normal pressure case. The correction takes the effect of pressurizing into account. The results show that the correction is reasonable and the method is applicable to combustion and heat transfer of the marine supercharged boiler.展开更多
基金supported by the Second Stage of Brain Korea 21 Projects
文摘Numerical study was performed to evaluate the characteristics of combined heat transfer of radiation, conduction and convection in indirect near infrared ray （N/R） heating chamber. The effects of important design parameters such as the shape of heat absorbing cylinder and heat releasing fin on the pressure drop and heat transfer coefficient were analyzed with different Reynolds numbers. The Reynolds numbers were varied from 103 to 3x106, which was defined based on the hydraulic diameter of the heat absorbing cylinder. Analyses were performed to obtain the inner and outer flow and the temperature distributions in the heat absorbing cylinder and the rates of radiation heat transfer and convection heat transfer. As the Reynolds number increases, the convection heat transfer rate is increased while the radiation heat transfer rate is decreased. The average convection heat transfer rate follows a power rule of the Reynolds number. Addition of three-dimensional heat releasing fin to the outside of the heat absorbing cylinder enhances the convection heat transfer.
文摘The present study deals with analytical investigation of temperature of a single burning iron particle.Three mathematical methods including AGM(Akbari-Ganji’s method),CM(Collocation method)and GM(Galerkin Method)are applied to solving non-linear differential governing equation and effectiveness of these methods is examined as well.For further investigation,forth order Runge-Kutta approach,a numerical method,is used to validate the obtained analytical results.In the present study,the developed mathematical model takes into account the effects of thermal radiation,convective heat transfer and particle density variations during combustion process.Due to particles’small size and high thermal conductivity,the system is assumed to be lumped in which the particle temperature does not change within the body and all of its regions are at the same temperature.The temperature distributions obtained by analytical methods have satisfactory agreement with numerical outputs.Finally,the results indicate that AGM is a more appropriate method than GM and CM due to its lower mean relative error and less run time.
文摘The effect of pressure on combustion and heat transfer is analyzed. The research is based on the basic combustion and heat transfer theorem. A correction for the heat calculation method for pressurized furnace is made on the basis of the normal pressure case. The correction takes the effect of pressurizing into account. The results show that the correction is reasonable and the method is applicable to combustion and heat transfer of the marine supercharged boiler.
