Effective emissivity of a blackbody cavity formed by two coaxial tubes.

A blackbody cavity is developed for continuously measuring the temperature of molten steel, which consists of a cylindrical outer tube with a flat bottom, a coaxial inner tube, and an aperture diaphragm. The ray-tracing approach based on the Monte Carlo method was applied to calculate the effective emissivity for the isothermal cavity with the diffuse walls. And the dependences of the effective emissivity on the inner tube relative length were calculated for various inner tube radii, outer tube lengths, and wall emissivities. Results indicate that the effective emissivity usually has a maximum corresponding to the inner tube relative length, which can be explained by the impact of the inner tube relative length on the probability of the rays absorbed after two reflections. Thus, these results are helpful to the optimal design of the blackbody cavity.

[1]  M. Ballico.  Modelling of the effective emissivity of a graphite black body , 1995 .

[2]  A. Prokhorov,et al.  Monte Carlo method in optical radiometry , 1998 .

[3]  R. E. Bedford,et al.  Emissivities of diffuse cavities, II: Isothermal and nonisothermal cylindro-cones , 1975 .

[4]  Akira Ono,et al.  Calculation of the directional emissivities of cavities by the Monte Carlo method , 1980 .

[5]  Leonard M. Hanssen,et al.  Effective emissivity of a cylindrical cavity with an inclined bottom: I. Isothermal cavity , 2009 .

[6]  R. E. Bedford,et al.  Emissivities of diffuse cavities: Isothermal and nonisothermal cones and cylinders , 1974 .

[7]  M. Shannon,et al.  Analysis of Monte Carlo methods applied to blackbody and lower emissivity cavities. , 2002, Applied optics.

[8]  S Chen,et al.  Emissivities of diffuse cavities. 4: Isothermal and nonisothermal cylindro-inner-cones. , 1985, Applied optics.

[9]  R. P. Heinisch,et al.  Radiant emission from baffled conical cavities , 1973 .

[10]  Fumihiro Sakuma,et al.  Effective emissivities of black-body cavities with grooved cylinders , 1998 .

[11]  A. Prokhorov,et al.  Calculation of the Effective Emissivities of Specular-Diffuse Cavities by the Monte Carlo Method , 1992 .

[12]  J. R. Howell,et al.  Monte carlo solution of thermal transfer through radiant media between gray walls. , 1964 .

[13]  Shumao Zhao,et al.  Estimation of Effective Diffusion Coefficient of Gaseous Species in MgO–C Refractories by Shrinking Core Model , 2012 .

[14]  R. E. Bedford,et al.  Emissivities of diffuse cavities. III. Isothermal and nonisothermal double cones , 1976 .