两个热辐射球体之间热辐射面与受热辐射面的计算

根据光的直线传播原理,导出两个热辐射球体之间的热辐射面和受热辐射面的一般表达式。

Convective heat and mass transfer in MHD mixed convection flow of Jeffrey nanofluid over a radially stretching surface with thermal radiation

Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary conditions through heat and mass are employed. The governing boundary layer equations are transformed into ordinary differential equations. Convergent series solutions of the resulting problems are derived. Emphasis has been focused on studying the effects of mixed convection, thermal radiation, magnetic field and nanoparticles on the velocity, temperature and concentration fields. Numerical values of the physical parameters involved in the problem are computed for the local Nusselt and Sherwood numbers are computed.

Effects of Clouds and Aerosols on Surface Radiation Budget Inferred from DOE AMF at Shouxian,China

Based on data collected during the first U.S. Department of Energy （DOE） Atmospheric Radiation Measurement （ARM） field campaigns at Shouxian, east- ern China in 2008, the effects of clouds and aerosols on the surface radiation budget during the period Octo- ber-December 2008 were studied. The results revealed that the largest longwave （LW）, shortwave （SW）, and net Aerosol Radiative Effects （AREs） are 12.7, -37.6, and -24.9 W rn-2, indicating that aerosols have LW warming impact, a strong SW cooling effect, and a net cooling ef- fect on the surface radiation budget at Shouxian during the study period 15 October-15 December 2008. The SW cloud radiative forcing （CRF） is -135.1 W m-2, much cooler than ARE （about 3.6 times）, however, the LW CRF is 43.6 W m 2, much warmer than ARE, and resulting in a net CRF of-91.5 W m-2, about 3.7 times of net ARE. These results suggest that the clouds have much stronger LW warming effect and SW cooling effect on the surface radiation budget than AREs. The net surface radiation budget is dominated by SW cooling effect for both ARE and CRE. Furthermore, the precipitatable clouds （PCs） have the largest SW cooling effect and LW warming ef- fect, while optically thin high clouds have the smallest cooling effect and LW warming on the surface radiation budget. Comparing the two selected caseds, CloudSat cloud radar reflectivity agrees very well with the AMF （ARM Mobile Facility） WACR （W-band ARM Cloud Radar） measurements, particularly for cirrus cloud case. These result will provide a ground truth to validate the model simulations in the future.

Reconstruction of Temperature Field in 3-D, Absorbing, Emitting, and Anisotropically Scattering Medium

The soft measurement technology of flame temperature field is an efficient method to learn the combustion status in furnace. Generally, it reconstructs the temperature field in furnace through the image of flame, which is a process to solve radiative inverse problem. In this paper, the flame of pulverized coal is considered as 3-D, absorbing, emitting, and anisotropically scattering non-gray medium. Through the study on inverse problem of radiative heat transfer, the temperature field in this kind of medium has been reconstructed. The mechanism of 3-D radiative heat transfer in a rectangular media, which is 2 m×3 m× 5 m and full of CO2, N2 and carbon particles, is studied with Monte Carlo method. The 3-D temperature field in this rectangular space is reconstructed and the influence of particles density profile is discussed.

Radiative entransy flux in enclosures with non-isothermal or non-grey,opaque,diffuse surfaces and its application

The spectral radiative entransy flux and the total radiative entransy flux are defined for the steady radiative heat transfer processes in enclosures composed of non-isothermal or non-grey, opaque, diffuse surfaces. Based on the definitions, the radiative entransy flux balance equation and the radiative entransy dissipation functions are introduced under spectral and total wavelength condition. Furthermore, the minimum principle of radiative entransy loss, the extreme principle of radiative entransy dissipation and the minimum principle of radiative thermal resistance are developed. The minimum prirlciple of radiative en- transy loss shows that the potential and the net radiative heat flux distribution which meet the control equations and the boundary conditions would make the radiative entransy loss minimum if the net radiative heat flux or the potential distribution of the radiative heat transfer system is given. The extreme principle of radiative entransy dissipation indicates that the minimum radiative entransy dissipation leads to the minimum average potential difference for the prescribed total radiative heat exchange and the maximum radiative entransy dissipation leads to the maximum radiative heat exchange for the prescribed average potential difference. Moreover, the minimum principle of radiative thermal resistance tells us that the aforementioned extreme values of radiative entransy dissipation both correspond to the minimum value of radiative thermal resistance. Application examples are given for the extreme principle of spectral radiative entransy dissipation and the minimum principle of spectral radiative thermal resistance, and the principles are proved to be applicable.