Radiant Transfer in Gas Filled Enclosures by Radiant Energy Absorption Distribution Method

2008 IEEE International Symposium on Electromagnetic Compatibility

Hashimoto

2008

Utilization of electromagnetic absorbers under high power is increasing to estimate performance of high power radars in anechoic chambers. Variation of absorption characteristics of absorbers is expected due to the generation of heat or temperature change. To suppress temperature increase, the absorber has to be cooled down in some kind of way. For example, the means are sending air to the absorber, loading radiating fin on the absorber, developing lattice structure in the absorber to increase heat transfer, and so on. In this paper, for the fundamental examination, the wind-chill factor by sending air to a heated¨/4 EM-absorber is evaluated by measuring the temperature distribution with and without air blasting. As a result, the maximum temperature 78[© C] is confirmed on the surface of the absorber without air blasting. Meanwhile the maximum temperature decreases to 70[© C] on the surface of the absorber with air blasting. Therefore, the wind-chill factor by the air blasting is verified.

Section: Introductionmentioning

confidence: 99%

Fundamental examination about cooling approach for a heated EM-wave absorber under high power injection

Watanabe

2008 IEEE International Symposium on Electromagnetic Compatibility

Hashimoto

2008

“…In this paper, first, we combined FDTD, Semi-Implicit Method for Pressure Linked Equations (SIMPLE) [4][5], Monte Carlo [6] and Radiative Energy Absorption Distribution (READ) [7] methods to calculate electromagnetic field and all the heat transfer phenomena of heat transport, heat transfer by air convection and heat radiation (It is called FDTD-SIMPLE-MR method.). And temperature distribution of λ/4 type EMabsorber using resistive film under high power injection is calculated using FDTD-SIMPLE-MR method and traditional FDTD-HTE method.…”

Section: Introductionmentioning

confidence: 99%

Temperature distribution of /spl lambda//4 type EM-absorber using resistive film under high power injection

Watanabe

Saito

2006 IEEE International Symposium on Electromagnetic Compatibility, 2006. EMC 2006.

et al. 2006

In this paper, first, FDTD, Semi-Implicit Method for Pressure Linked Equations (SIMPLE), Monte Carlo and Radiative Energy Absorption Distribution (READ) methods are combined to calculate electromagnetic field and all the heat transfer phenomena of heat transport, heat transfer by air convection and heat radiation (It is called FDTD-SIMPLE-MR method.). The temperature distribution of λ/4 type EM-absorber using resistive film under high power injection is calculated using FDTD-SIMPLE-MR method and a traditional method. Next, the high power injection experiment is conducted using an absorber and high power RF instruments to get the temperature distribution experimentally. Finally, the calculated and measured temperature distributions of the absorber are compared. As a result, the calculated temperature distribution by FDTD-SIMPLE-MR method agrees well with the measured one and the validity of FDTD-SIMPLE-MR method is confirmed.

Monte Carlo method for radiative heat transfer analysis of general gas‐particle enclosures

Numerical Meth Engineering

Yang

Kudo

et al. 1988

SUMMARYA new Monte Carlo method is developed to analyse multi-dimensional radiative heat transfer in an enclosure containing grey gas with anisotropically scattering grey particles. One set of variables, called READ (Radiative Energy Absorption Distribution), is introduced to represent radiative transfer, thus appreciably reducing repeated computations required by the conventional Monte Carlo technique. A 1 m x 1 m square duct is used as the enclosure with the upper and lower walls at different temperatures in the one-dimensional case and with adiabatic specular or diffuse side walls in the two-dimensional case. Results agree well with the existing analytical solutions for one-dimensional, non-scattering cases. It is concluded that, with anisotropic scattering, an increase in the absorption coefficient and/or single scattering albedo produces adverse effects on radiative heat transfer. Anisotropic scattering effects cannot be simulated by the use of the effective absorption coefficient.