Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
GENERATION OF THE EMITTANCE DATA FOR DIFFERENT TEMPERATURES, TOTAL PRESSURES AND MOLAR RATIOS FOR A CO2-H2O MIXTURE AT HIGH PRESSURES
Submission Author:
Guilherme Etges , RS
Co-Authors:
Guilherme Etges, Francis França
Presenter: Felipe Ramos Coelho
doi://10.26678/ABCM.ENCIT2022.CIT22-0285
Abstract
This paper is a sequence of a previous work, in which it was studied the emittance for different factors for a CO2 and H2O mixture. The emittance for chemical species in a participating media, like the one that is under investigation in this study composed of CO2 and H2O, is the ratio of the total emitted radiation in a chosen path that it is not absorbed by, over the radiation emitted by a black body at the same temperature. It depends on the path chosen, and it varies due to certain characteristics of its state, such as its temperature, total pressure and molar fraction. The goal of this paper is to expand the results from previous studies and to introduce a new simplification of the process by changing the discretisation with the increase of the pressure, and comparing the results to see the impact in the final results. In order to do so, it will be generated results of the emittance of the two gases CO2 and H2O for a different set of combinations of molar fractions of the mixture, temperatures, ranging from 300 K to 2500 K and total pressures equals and over the atmospheric value. The last study, due to the increase of the computational costs with the increase of the total pressure using a fixed discretisation, was limited to 10 atm. Here, it will be expanded to even higher pressures until 40 atm. Using this range of temperature (from 300 K to 2500 K) and total pressure (equal and beyond the atmospheric) we can use the Lorentz profile to calculate the absorption coefficient over the desired spectrum length. Then, using the absorption coefficients it is possible to calculate the emittance values for a specific arrangement. The idea is to evaluate the influence of each of these variables over the total value of the emittance and compile a database of the results. The emittances here presented are calculated using a Fortran code and uses the high resolution spectral database HITEMP-2010 as a base to calculate the absorption coefficients. The results obtained in this study can be later on used to generate new WSGG correlations and be studied to make new models to facilitate and validate calculations in the area of thermal radiation.
Keywords
thermal radiation, emittance, HITEMP-2010
