Analysis of entropy generation and exergy losses of iso-octane and n-butanol adiabatic constant-volume combustion process

摘要

Butanol is a promising bio-fuel. Using iso-octane as gasoline surrogate, the entropy production and exergy balance of n-butanol and isooctane constant volume combustion process were analysed with the CHEMKIN software by considering detailed n-butanol and iso-octane chemical reaction mechanisms. The results of exergy balance analysis showed that, during the adiabatic constant-volume combustion process, there is a trade-off between exergy destruction and exergy loss due to incomplete combustion. The exergy destruction of n-butanol is obviously higher than that of iso-octane. The results of entropy generation analysis showed that, with high initial temperature, two apparent peaks of heat release rate and exergy loss rate are observed both for iso-octane and n-butanol. During combustion process, the internal energy exchange between high temperature product and the unburned reactant via a series of chemical reactions, especially the reactions of small molecule intermediate products, is the major reason for the exergy destruction.