Eventos Anais de eventos
CONEM 2022
XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
EMITTANCE ANALYSIS FOR DIFFERENT TEMPERATURES, TOTAL PRESSURES AND MOLAR RATIOS FOR A CO2-H2O MIXTURE
Submission Author:
Guilherme Etges , RS
Co-Authors:
Guilherme Etges, Bruno de Luca Zimmer Gomes, Francis França
Presenter: Francis França
doi://10.26678/ABCM.CONEM2022.CON22-0720
Abstract
The emissivity of a given surface is the ratio of the energy that is emitted by the surface over the energy emitted by a black surface at the same temperature. It is also possible to calculate the emittance for participating gases such as CO2 or H2O. In this case, it will be the ratio of the total emitted radiation along a certain path in the medium (and not absorbed) over the radiation emitted by a black body at the same temperature. It depends on the path chosen, and varies due to certain characteristics of its state, such as its temperature, total pressure and molar fraction. The present paper aims at analyzing and comparing emittance of mixtures of CO2 and H2O for a different set of combinations of temperatures, ranging from 300 K to 2500 K, considering different pressures of 1.0, 2.0, 5.0 and 10 atm, and molar fractions of 0.1 and 0.2 for both CO2 and H2O. Using this set of choices for temperature (between 300 K and 2500 K) and total pressure (equal and above the atmospheric) one 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 thermal condition and a certain path length. 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 are calculated using a Fortran code and uses the high resolution spectral database HITEMP2010 as a base to calculate the absorption coefficients. The results can be later on used to generate, for example, new WSGG correlations and be studied to make new models to facilitate and validate calculations of thermal radiation in CO2 /H2O mixtures.
Keywords
thermal radiation, emittance, HITEMP-2010, participating gases, spectral lines
