Importance of Combined Lorentz-Doppler Broadening in High-Temperature Radiative Heat Transfer Applications

2004 ◽  
Vol 126 (5) ◽  
pp. 858-861 ◽  
Author(s):  
Anquan Wang ◽  
Michael F. Modest
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Critical Temperature ◽  
Absorption Coefficient ◽  
Radiative Heat Transfer ◽  
Total Pressure ◽  
Radiative Heat ◽  
Narrow Band ◽  
Spectral Lines ◽  
Doppler Broadening

The importance of combined Lorentz-Doppler (or Voigt) broadening of spectral lines in high-temperature radiative heat transfer applications is investigated. Employing narrow-band transmissivities as the criterion, the critical total pressure below which, and the critical temperature above which Doppler broadening has a significant effect on the absorption coefficient is established for gaseous H2O and CO2.

scholarly journals Effect of pressure broadening on the radiative heat transfer by CO and CH4 gases using line by line method with latest high-temperature database

2021 ◽  
pp. 319-319
Author(s):  
Yu Yang ◽  
Shu Zheng ◽  
Yuzhen He ◽  
Mingxin Xu ◽  
Zixue Luo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Absorption Coefficient ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Pressure Effect ◽  
Pressure Effects ◽  
Line Broadening ◽  
Pressure Broadening ◽  
Elevated Pressures

As the development of current propulsion technology such as gas turbine and rocket chamber moving to higher working pressure, the radiative parameters of fuel, such as CH4or CO, are required at elevated pressures, which in some cases are calculated without considering the pressure effect of line broadening. To investigate the pressure effect of line broadening on the radiative heat transfer, the radiative heat sources of a one-dimensional enclosure filled with CH4/CO and Planck mean absorption coefficients at elevated pressures were calculated using the statistical narrow band(SNB)and line by line (LBL)methods. The radiative parameters were conducted using high-temperature molecular spectroscopic(HITEMP)2019 (for CO) and HITEMP 2020 (for CH4) databases. The results showed that the pressure effect of line broadening on the calculations of radiative heat source of CH4can be ignored when HITEMP 2020 database was used. For CO medium, the pressure effect of line broadening was over 40% at 30 atm in all cases whichever methods and databases were used. The pressure broadening has a strong effect on the Planck mean absorption coefficient below 1000 K for CH4 and at the temperature of 500-900K for CO at 30 atm. The maximum pressure effects were 22% for CH4 and 18% for CO at 30 atm, which illustrated the pressure effect of line broadening needed to be taken into account in the calculation of Planck mean absorption coefficient.

scholarly journals The Treatment of Nongray Properties in Radiative Heat Transfer: From Past to Present

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Michael F. Modest
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Radiative Heat Transfer ◽  
Historical Development ◽  
Radiative Heat ◽  
State Of The Art ◽  
Participating Media ◽  
Box Models ◽  
Property Data ◽  
Gradual Development

Radiative heat transfer in high-temperature participating media displays very strong spectral, or “nongray,” behavior, which is both very difficult to characterize and to evaluate. This has led to very gradual development of nongray models, starting with primitive semigray and box models based on old experimental property data, to today's state-of-the-art k-distribution approaches with properties obtained from high-resolution spectroscopic databases. In this paper a brief review of the historical development of nongray models and property databases is given, culminating with a more detailed description of the most modern spectral tools.

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