Liquid fuel spray atomisation, ignition and combustion dynamics
File(s)
Author(s)
Gallot Lavallee, Simon
Type
Thesis
Abstract
Turbulent spray
ames are increasingly found in industrial combustion devices due to greater
demand for fuel
exibility. However, a comprehensive model of the underlying physics involved
into this is still lacking due to the great complexity of the problem. The importance of numerical
studies in this context is related to the possible savings in experimental testing both in terms
of time and resources. A detailed yet a ordable numerical tool is therefore required to the
development of less polluting and more e cient devices.
This work aims at the validation of existing models and developing methods focusing on the
atomisation, evaporation, ignition, and combustion dynamics of spray fuelled burners. Here,
extensive simulations are performed in the context of Large Eddy Simulation (LES) where the
scalar elds are modelled using a transported pdf approach. The solution of the latter is obtained
by means of the Eulerian stochastic eld method, a
exible and comprehensive combustion
model. The liquid phase is treated in a discrete Lagrangian fashion, where the sub-grid-scale
uctuations from the LES are accounted for by the stochastic parcel method for dispersion,
break-up and evaporation.
Di erent atomisation and evaporation models of increasing complexity are tested and greater
insight on the e ect of this choice is provided. This is achieved while exploring the applicability of
the method to various state of the art techniques for pollutants reduction. Several test cases have
been simulated: the Sandia constant volume chamber, the DELFT hot co-
ow burner and two of
the burners from CORIA laboratories. For all cases good reproduction of the aerodynamic elds
as well as the qualitative
ame shapes is acheived. Three evaporation model have been tested,
and three break-up models used for the simulations and the e ects of this choice are explored
in this work. The stochastic break-up model tested allows for reduced a priori assumption on
the calculation providing results comparable with other methods. The Abramzon-Sirignano
evaporation model appears to be a valid evaporation model to be employed in dilute spray LES
calculations. Validation is achieved by comparing both gas and liquid phase properties with the
available experimental data. An important dependency of the quality of the predictions on the
choice of the chemical mechanism describing the oxidation process is observed. As a conclusion
of the study, future directions are suggested together with some preliminary illustrative results.
ames are increasingly found in industrial combustion devices due to greater
demand for fuel
exibility. However, a comprehensive model of the underlying physics involved
into this is still lacking due to the great complexity of the problem. The importance of numerical
studies in this context is related to the possible savings in experimental testing both in terms
of time and resources. A detailed yet a ordable numerical tool is therefore required to the
development of less polluting and more e cient devices.
This work aims at the validation of existing models and developing methods focusing on the
atomisation, evaporation, ignition, and combustion dynamics of spray fuelled burners. Here,
extensive simulations are performed in the context of Large Eddy Simulation (LES) where the
scalar elds are modelled using a transported pdf approach. The solution of the latter is obtained
by means of the Eulerian stochastic eld method, a
exible and comprehensive combustion
model. The liquid phase is treated in a discrete Lagrangian fashion, where the sub-grid-scale
uctuations from the LES are accounted for by the stochastic parcel method for dispersion,
break-up and evaporation.
Di erent atomisation and evaporation models of increasing complexity are tested and greater
insight on the e ect of this choice is provided. This is achieved while exploring the applicability of
the method to various state of the art techniques for pollutants reduction. Several test cases have
been simulated: the Sandia constant volume chamber, the DELFT hot co-
ow burner and two of
the burners from CORIA laboratories. For all cases good reproduction of the aerodynamic elds
as well as the qualitative
ame shapes is acheived. Three evaporation model have been tested,
and three break-up models used for the simulations and the e ects of this choice are explored
in this work. The stochastic break-up model tested allows for reduced a priori assumption on
the calculation providing results comparable with other methods. The Abramzon-Sirignano
evaporation model appears to be a valid evaporation model to be employed in dilute spray LES
calculations. Validation is achieved by comparing both gas and liquid phase properties with the
available experimental data. An important dependency of the quality of the predictions on the
choice of the chemical mechanism describing the oxidation process is observed. As a conclusion
of the study, future directions are suggested together with some preliminary illustrative results.
Version
Open Access
Date Issued
2017-09
Date Awarded
2018-04
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Jones, William P
Navarro-Martinez, Salvador
Sponsor
General Electric Power
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)