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

Abstract

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 CH4 or 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 1-D enclosure filled with CH4/CO and Planck mean absorption coefficients at elevated pressures were calculated using the statistical narrow band and line-by-line 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 CH4 can be ignored when HITEMP 2020 database was used. For CO medium, the pressure effect of line broadening was over 40% at 30 atmosphere 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 500-900 K for CO at 30 atmosphere. The maximum pressure effects were 22% for CH4 and 18% for CO at 30 atmosphere, which illustrated the pressure effect of line broadening needed to be taken into account in the calculation of Planck mean absorption coefficient.