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

Authors: Hongqing Feng; Jing Zhang; Daojian Liu; Zunqing Zheng; Xiaodong Zhang

Addresses: Department of Energy and Power Engineering, China University of Petroleum, Qingdao, 266580, China ' Department of Energy and Power Engineering, China University of Petroleum, Qingdao, 266580, China ' State Key Laboratory of Engine, Tianjin University, Tianjin, 300072, China ' State Key Laboratory of Engine, Tianjin University, Tianjin, 300072, China ' Key Laboratory of Biomass Gasification Technology of Shandong, Jinan, 250014, China

Abstract: Butanol is a promising bio-fuel. Using iso-octane as gasoline surrogate, the entropy production and exergy balance of n-butanol and iso-octane 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.

Keywords: bio-butanol; iso-octane; constant-volume combustion; exergy balance; entropy generation.

DOI: 10.1504/IJEX.2017.086861

International Journal of Exergy, 2017 Vol.24 No.1, pp.82 - 104

Received: 24 Mar 2017
Accepted: 17 Jul 2017
Published online: 01 Oct 2017 *

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