Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Askari, Omid

Committee Member

Bhushan, Shanti

Committee Member

Li, Like

Committee Member

Singh, Prashant

Date of Degree

4-30-2021

Original embargo terms

Complete embargo for 1 year

Document Type

Dissertation - Open Access

Major

Mechanical Engineering

Degree Name

Doctor of Philosophy

College

James Worth Bagley College of Engineering

Department

Department of Mechanical Engineering

Abstract

With the increase of global temperature and decrease of fossil fuel sources, biofuels become an excellent alternative in present days. Because of its oxygenated nature, biofuels are found to be more environmentally friendly over fossil fuels. Therefore, in this study, initially two different biofuels: ethanol and 2,5 dimethyl furan (DMF) are considered as an additive to gasoline which shows a significant improvement in its combustion characteristics. Due to this promising result for further studies of these biofuel, details chemical kinetic study of biofuels is considered in this work through generating its mechanism for engine relevant conditions. Detail chemical mechanism PCRL-Mech1 is generated for ethanol which is applicable for wide range of operating conditions. The mechanism is successfully validated with available experimental data of laminar burning speed (LBS) and ignition delay time (IDT). Species concentration at different reactor conditions are also considered for the comparison which shows an excellent agreement. Detail mechanism generation for another newer biofuel anisole is also considered because of its favorable features in combustion properties and potential source of biomass. Anisole is a higher hydrocarbon aromatic component and comparative newer fuel which has limited experimental data. However, with that available experimental data, the developed anisole mechanism shows a good agreement predicting LBS and IDT results. The chemical kinetics of this fuel is also analyzed through reaction path flux and sensitivity analyses. Although, detail mechanisms have higher accuracy, they would be very expensive when using in multiscale computational fluid dynamics (CFD) modeling. Therefore, different mechanism reduction schemes are considered to reduce the mechanism size. Initially direct relation graph (DRG), direct relation graph with error propagation (DRGEP) and sensitivity analysis is implemented to generate a skeleton mechanism for PCRL-Mech1, which successfully reduced its size. In addition, the rate-controlled constraint equilibrium (RCCE) analysis is considered as a reduction scheme. The constraints for RCCE calculation are selected through approximate singular value decomposition of actual degree of disequilibrium (ASVDADD) analysis. A good comparison of temperature profile of RCCE simulation proves the success of ASVDADD method.

Available for download on Monday, May 16, 2022

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