Mechanical Engineering, Urmia University
Energy and exergy concepts come from thermodynamics laws and are applicable to all fields of science and engineering. This study considers numerical simulations of combustion of hydrogen with air in a constant pressure environment and exergy terms according to first and second laws analysis using homemade code. Chemical kinetic model includes 20 reactions and 9 species. At the first stage of present study, the effects of airl-fuel ratio (φ) on energy and exergy terms are investigated for different φ (from 0·6 to 1·4) at constant temperature 1000 (K). The predictions show that the increase of φ from 0·6 to 1 increases average temperature, thermo-mechanical and chemical exergys and ireversibilty, while increase of φ from 1 to 1.4 decreases them, except for chemical and total exergys. Also second- law efficiency increases with increasing of φ. At the second stage, at φ=1.4, in which the second-law efficiency is maximum, initial temperature of mixture ( is varied from1000 to 1400 (K) by 100 (K) step. The predictions show that increase of from 1000 to 1100 (K) increases average temperature, thermomechanical, total exergy and irreversibility while decreases the chemical exergy and second-law efficiency. Also, the increase of from 1100 to 1400 (K) increases the thermo-mechanical, chemical total exergys and second-law efficiency, while irreversibility decreases. It was found that second-law efficiency reaches a maximum value in the case of higher airl-fuel ratio and initial temperature.