Analysis of NO Formation and Entropy Generation in a Reactive Flow

Abstract

A comprehensive investigation of turbulent combustion is accomplished to study the relationship between nitrogen oxide (NO) formation and entropy generation distribution in a non-premixed propane combustion. The radiation heat transfer and combustion are simulated, employing the discrete ordinates model and laminar flamelet model, respectively. A post processing model is employed to estimate the NO formation rate. The present results of NO species formation, mean temperature and velocity are compared with the existing experimental data, and good agreements are obtained. It is shown that the main region of total entropy generation rate and NO formation rate is at the same axial position. The entropy generation distribution may be defined as an index by which the combustion region and main region of NO formation are predicted. However, total entropy generation rate is more sensitive to high temperature (1500–1930 K) than that of NO formation rate. With an increase of 28.7% in temperature, the entropy generation and NO formation rates rise by 900% and 127%, respectively. The occurrence of chemical reactions plays the major role in the generation of entropy.