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Numerical Study of The Effect of Chemical Mechanism and Dynamic EDC Combustion Model on The Modeling of Kerosene Spray Flame of Sharif MILD Test Rig (SMSTR)

Torkanlou, Ali | 2025

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 58038 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Mardani, Amir
  7. Abstract:
  8. In this study, the numerical simulation of MILD spray combustion of kerosene in preheated and oxygen-diluted air is conducted in the SMSTR combustion test rig at Sharif University of Technology. Considering the importance of understanding various aspects of this combustion regime, a numerical model has been developed, and using the EDC combustion model, the effects of parameters such as inlet oxygen concentration, inlet air temperature, chemical kinetics, and volume fraction/time scale constants on functional parameters like flame structure, flame lift-off height, temperature field distribution, and mass fraction ratio of combustion species in the reaction zone have been investigated. To develop the numerical model, physical flow parameters such as turbulence intensity, DPM time step, and volume fraction/time scale constants of EDC model are determined. Additionally, the investigation of the chemical mechanism shows that the ignition delay time phenomenon is significant in the results of the kerosene spray combustion domain. Subsequently, by applying the obtained results to a dynamic EDC model developed by Moradani and Nazari at the Aerospace Department of Sharif University for methane gas fuel—in which volume fraction and time scale constants are calculated based on the Kolmogorov time scale and a specific reaction rate—we attempt to examine and develop this model for liquid kerosene fuel and the SMSTR under MILD combustion conditions. This model has shown significantly higher accuracy in the studied cases compared to the default EDC model. In the zonal coefficient method, it is demonstrated that selecting a base reaction is crucial for reducing simulation error compared to the default state, and the importance of the ignition delay time phenomenon on flame lift-off height is also shown in this method. Finally, physical flow parameters such as turbulence intensity with a value of 10% at the inlet boundary, DPM time step with a value of 5×〖10〗^(-6) s, and the constants of EDC model with values of C_γ=5 and C_τ=0.2, show the best performance in simulating the kerosene flame. The choice of fuel type can also affect the selection of EDC constants, as applying suggested values for a gaseous fuel does not necessarily guarantee flame formation for a liquid fuel
  9. Keywords:
  10. Moderate or Intense Low Axygen Dilution (MILD) ; Numerical Simulation ; Kerosene ; Eddy Dissipation Concept (EDC)Model ; Pressure-Swirl Injectors ; Chemical Mechanism

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