The dispersion of pollutants in urban environments is a major problem. Because of this fact our study comes to propose prevention and security system against the dispersion of releases and fumes from industrial smokes...The dispersion of pollutants in urban environments is a major problem. Because of this fact our study comes to propose prevention and security system against the dispersion of releases and fumes from industrial smokestacks. The system is modeled by a plume-thermosiphon interaction flow resulting from a vertical cylinder open at both ends with a generating source of the plume centered at the opening of the cylinder. The cylindrical wall heats under the effect of the thermal radiation emitted by the generator source, which causes a flow of thermosiphon around the flow of the thermal plume. In order to determine the radiosity of radiation leaving the wall we have been used the Simpson quadrature and the Gaussian elimination method with a dominant pivot. Numerical simulations have been executed for different positions of the thermosiphon compared to the plume source, and for a number of Rayleigh fixed Ra = 10＋7, and a radius of the hot source corresponds to R＊ = 0.46. The results oftbe numerical model that we have been developed, help first identify the behavior of pollutants from the dynamic and thermal point of view and then explore the different locations of the thermosiphon compared to the source of the plume which causes a major influence on the dispersion of pollutants.展开更多
In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion w...In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion were presented.展开更多
In this paper,the performance of a solar thermal system with a focus on space heating was investigated.A 70 m^(2) detached house was considered in the weather conditions of the city of Tehran,Iran.A thermosyphon solar...In this paper,the performance of a solar thermal system with a focus on space heating was investigated.A 70 m^(2) detached house was considered in the weather conditions of the city of Tehran,Iran.A thermosyphon solar water heater with a flat plate collector combined with an auxiliary electrical heater supplies the heating demand of the house.The proposed system was modeled and analyzed using TRNSYS software.In this regard,the TRNBuild module was employed for the building load calculation.The model has been simulated for one year of operation.The effects of the solar collector’s surface area and storage volume were assessed.The results show that for a solar collector with a 15 m^(2) surface area,the solar fraction is 0.29 in January,during which the solar radiation is the lowest.Using solar collectors of10 m^(2) and 5 m^(2) surface areas,the solar fraction falls to 0.23 and 0.14,respectively in January.Besides,two cases of 150 L and 300 L storage tanks are taken into account.Eventually,it is found that using a 15 m^(2) solar collector and a 150 L storage tank can appropriately provide the building’ s heating demand taking the thermal performance and economic aspects into consideration.展开更多
文摘The dispersion of pollutants in urban environments is a major problem. Because of this fact our study comes to propose prevention and security system against the dispersion of releases and fumes from industrial smokestacks. The system is modeled by a plume-thermosiphon interaction flow resulting from a vertical cylinder open at both ends with a generating source of the plume centered at the opening of the cylinder. The cylindrical wall heats under the effect of the thermal radiation emitted by the generator source, which causes a flow of thermosiphon around the flow of the thermal plume. In order to determine the radiosity of radiation leaving the wall we have been used the Simpson quadrature and the Gaussian elimination method with a dominant pivot. Numerical simulations have been executed for different positions of the thermosiphon compared to the plume source, and for a number of Rayleigh fixed Ra = 10＋7, and a radius of the hot source corresponds to R＊ = 0.46. The results oftbe numerical model that we have been developed, help first identify the behavior of pollutants from the dynamic and thermal point of view and then explore the different locations of the thermosiphon compared to the source of the plume which causes a major influence on the dispersion of pollutants.
文摘In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion were presented.
文摘In this paper,the performance of a solar thermal system with a focus on space heating was investigated.A 70 m^(2) detached house was considered in the weather conditions of the city of Tehran,Iran.A thermosyphon solar water heater with a flat plate collector combined with an auxiliary electrical heater supplies the heating demand of the house.The proposed system was modeled and analyzed using TRNSYS software.In this regard,the TRNBuild module was employed for the building load calculation.The model has been simulated for one year of operation.The effects of the solar collector’s surface area and storage volume were assessed.The results show that for a solar collector with a 15 m^(2) surface area,the solar fraction is 0.29 in January,during which the solar radiation is the lowest.Using solar collectors of10 m^(2) and 5 m^(2) surface areas,the solar fraction falls to 0.23 and 0.14,respectively in January.Besides,two cases of 150 L and 300 L storage tanks are taken into account.Eventually,it is found that using a 15 m^(2) solar collector and a 150 L storage tank can appropriately provide the building’ s heating demand taking the thermal performance and economic aspects into consideration.
