CFD modelling of gas-turbine: Fuel droplet heating, evaporation and combustion

In this study, we have conducted a detailed analysis of kerosene fuel droplet heating and evaporation, using the previously developed discrete component model (DCM). Kerosene fuel composition (approximated by 44 components of the full composition) is replaced with 2 surrogate components to reduce the computational time. In contrast to the classical industrial analyses of aviation fuel (e.g. the single-component, or distillation curve methods), the DCM takes into account gradients of species mass fractions in droplets. It is based on the analytical solutions to the heat transfer and species diffusion equations subject to appropriate boundary and initial conditions. Numerical codes using these solutions were extensively verified and validated in our previous work. The effective thermal conductivity and effective diffusivity approaches for moving droplets are used in the model.
The DCM was implemented in the commercial CFD software of ANSYS-Fluent. This opens opportunities for the simulation of the full combustion cycle. The influence of droplet evaporation on the combustion process has been investigated. The preliminary results show that the fuel composition and temperature gradient inside droplet, which are ignored in the original version of ANSYS Fluent, lead to noticeable impact on the spray formation and combustion processes. The new results have been compared with those reported in the literature, a general agreement between these results has been demonstrated. Finally, the combustion of the blended fuel droplets has been simulated, and the influence of fuel evaporation and species diffusion on flame properties have been investigated.