Numerical modelling of natural gas combustion

Hu, M 2013, Numerical modelling of natural gas combustion, Masters by Research, Aerospace, Mechanical and Manufacturing Engineering, RMIT University.


Document type: Thesis
Collection: Theses

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Title Numerical modelling of natural gas combustion
Author(s) Hu, M
Year 2013
Abstract A numerical model with detailed reaction mechanism which is tailored for studying the behaviour of combustion of natural gas has been introduced and validated with available experimental data. The numerical model attempts to comprehensively simulate the physical conditions (temperature and pressure), equivalent ratio, fuel dilution and strain rate effect in the laminar flames. Studies on different kinds of reaction mechanism were also performed. Detailed mechanisms with hundreds of elementary reactions and species are available for the combustion of alkanes as a result of the consistent pursuit of mechanism development over several decades. The mechanism consists 325 elementary chemical reactions and 53 species for natural gas combustion. The optimized conditions for the mechanism is 1000 to 2500 K and 10 Torr to 10 atm. The experimental data of laminar flame speed and species concentration profiles are used to validate this kinetic mechanism for natural gas combustion. Numerical study on premixed burner models has been carried out. The general theory of its embedded thermo-physical behaviour is discussed. In addition, experimental literatures are reviewed; methods of experiments and their associated advantages and limitation were also presented. Experimental measurements of laminar flame speed of methane and ethane had been presented at standard and elevated pressure and temperature over wide range of fuel-air equivalence ratio. In general, premixed laminar flame model by CHEMKIN produced the best agreement with experimental data. The model is considered as a suitable candidate for considering. Finally numerical study of laminar diffusion flame is presented by non-premixed burner models. The model was applied to simulate the effects of fuel dilution and strain rate on the laminar flames. The computed results compared well with the measured data. Laminar diffusion flamelet approach is introduced to predict highly non-equilibrium flame. By using this approach, chemical kinetic effects can be incorporated into turbulent flames with significantly reducing the required computing time to solve the fire problems. The detailed kinetic mechanism and numerical models (premixed and non-premixed) have been introduced to simulate the oxidation of hydrocarbons up to C2 species under various conditions. The computed laminar flame speed and structure are in a good agreement with experimental data.
Degree Masters by Research
Institution RMIT University
School, Department or Centre Aerospace, Mechanical and Manufacturing Engineering
Keyword(s) Modelling
Natural Gas
Combustion
Premixed
Diffusion
Laminar Flamelet
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Created: Wed, 29 Jan 2014, 14:04:36 EST by Brett Fenton
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