An experimental study of the thermal characteristics of an existing office building with double skin facade DSF were conducted in hot summer daytime in Nanjing China. The temperature distributions of the DSF and indoo...An experimental study of the thermal characteristics of an existing office building with double skin facade DSF were conducted in hot summer daytime in Nanjing China. The temperature distributions of the DSF and indoor environment were measured at different control modes of DSF.The results show that the energy consumption of the air conditioning system in room B with opened exterior vents a closed interior facade and an air cavity with shading was 21.0% less than that in room A with closed exterior vents a closed interior facade and air cavity without shading in 9.5 h. The temperature distributions of the DSF and indoor environment in both horizontal and vertical directions were decisively influenced by shading conditions. The usage of shading devices strengthens the stack effect on the air cavity. Compared to room A the temperature distribution in room B is more uniform with smaller fluctuations.Meanwhile the problem of overheating in the air cavity of the DSF is still present in all tested conditions.展开更多
This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid...This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid properties, slip velocity, and internal heat generation/absorption. The flow in boundary layer is considered to be generated solely by the stretching of the sheet adjacent to porous medium with boundary wall slip condition. Highly nonlinear momentum and thermal boundary layer equations governing the flow and heat transfer are reduced to set of nonlinear ordinary differential equations by appropriate transformation. The resulting ODEs are successfully solved numerically with the help of shooting method. Graphical results are shown for non-dimensional velocities and temperature. The effects of heat generation/absorption parameter, the porous parameter, the viscoelastic parameter, velocity slip parameter, variable thermal conductivity and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction coefficient and Nusselt number are presented. Comparison of numerical results is made with the earlier published results under limiting cases.展开更多
The effect of mesa size on th e thermal characteristics of etched mesa vertical-cavity surface-emitting lase rs(VCSELs) is studied. The numerical results show that the mesa size of the top mirror strongly influences t...The effect of mesa size on th e thermal characteristics of etched mesa vertical-cavity surface-emitting lase rs(VCSELs) is studied. The numerical results show that the mesa size of the top mirror strongly influences the temperature distribution inside the etched mesa V CSEL. Under a certain driving voltage, with decreasing mesa size, the location o f the maximal temperature moves towards the p-contact metal, the temperature in the core region of the active layer rises greatly, and the thermal characterist ics of the etched mesa VCSELs will deteriorate.展开更多
According to 350 MW and 600 MW boilers,under oxygen fuel condition,through the reasonable control of the primary and secondary flow and the correct option and revision of mathematical model,the temperature distributio...According to 350 MW and 600 MW boilers,under oxygen fuel condition,through the reasonable control of the primary and secondary flow and the correct option and revision of mathematical model,the temperature distribution,heat flux distribution and absorption heat distribution,etc.was obtained which compared with those under air condition.Through calculation,it is obtained that the primary and secondary flow mixed well,good tangentially fired combustion in furnace was formed,the temperature under air condition obviously higher than the temperature under O26 condition.The adiabatic flame temperature of wet cycle was slightly higher than that of dry cycle.The maximum heat load appeared on the waterwall around the burner area.The heat load gradually decreased along the furnace height up and down in burner area.The heat absorption capacity of the furnace under O26 was lower than that under the air condition.The heat absorption capacity of the platen heating surface under 026 was equal to that under air condition.And the heat absorbing capacity of waterwall under O26 was about 7%~12% less than that under air condition.展开更多
基金The National Natural Science Foundation of China(No.51308295,51206080)China Postdoctoral Science Foundation(No.2013M531368)
文摘An experimental study of the thermal characteristics of an existing office building with double skin facade DSF were conducted in hot summer daytime in Nanjing China. The temperature distributions of the DSF and indoor environment were measured at different control modes of DSF.The results show that the energy consumption of the air conditioning system in room B with opened exterior vents a closed interior facade and an air cavity with shading was 21.0% less than that in room A with closed exterior vents a closed interior facade and air cavity without shading in 9.5 h. The temperature distributions of the DSF and indoor environment in both horizontal and vertical directions were decisively influenced by shading conditions. The usage of shading devices strengthens the stack effect on the air cavity. Compared to room A the temperature distribution in room B is more uniform with smaller fluctuations.Meanwhile the problem of overheating in the air cavity of the DSF is still present in all tested conditions.
文摘This study examines theoretically and computationally the non-Newtonian boundary layer flow and heat transfer for a viscoelastic fluid over a stretching continuous sheet embedded in a porous medium with variable fluid properties, slip velocity, and internal heat generation/absorption. The flow in boundary layer is considered to be generated solely by the stretching of the sheet adjacent to porous medium with boundary wall slip condition. Highly nonlinear momentum and thermal boundary layer equations governing the flow and heat transfer are reduced to set of nonlinear ordinary differential equations by appropriate transformation. The resulting ODEs are successfully solved numerically with the help of shooting method. Graphical results are shown for non-dimensional velocities and temperature. The effects of heat generation/absorption parameter, the porous parameter, the viscoelastic parameter, velocity slip parameter, variable thermal conductivity and the Prandtl number on the flow and temperature profiles are presented. Moreover, the local skin-friction coefficient and Nusselt number are presented. Comparison of numerical results is made with the earlier published results under limiting cases.
基金National High Technology Research and Development Programof China(2001AA312180)
文摘The effect of mesa size on th e thermal characteristics of etched mesa vertical-cavity surface-emitting lase rs(VCSELs) is studied. The numerical results show that the mesa size of the top mirror strongly influences the temperature distribution inside the etched mesa V CSEL. Under a certain driving voltage, with decreasing mesa size, the location o f the maximal temperature moves towards the p-contact metal, the temperature in the core region of the active layer rises greatly, and the thermal characterist ics of the etched mesa VCSELs will deteriorate.
文摘According to 350 MW and 600 MW boilers,under oxygen fuel condition,through the reasonable control of the primary and secondary flow and the correct option and revision of mathematical model,the temperature distribution,heat flux distribution and absorption heat distribution,etc.was obtained which compared with those under air condition.Through calculation,it is obtained that the primary and secondary flow mixed well,good tangentially fired combustion in furnace was formed,the temperature under air condition obviously higher than the temperature under O26 condition.The adiabatic flame temperature of wet cycle was slightly higher than that of dry cycle.The maximum heat load appeared on the waterwall around the burner area.The heat load gradually decreased along the furnace height up and down in burner area.The heat absorption capacity of the furnace under O26 was lower than that under the air condition.The heat absorption capacity of the platen heating surface under 026 was equal to that under air condition.And the heat absorbing capacity of waterwall under O26 was about 7%~12% less than that under air condition.
