Large eddy simulation of spray combustion using the spray flamelet/progress variable model: Further extension and validation

Abstract

The classical flamelet combustion model assumes that the combustion system consists of two homogeneous inlet streams for oxidizer and fuel. It usually requires extension and validation for configurations with different types of inlet streams. In the current work, the recently developed two-phase spray flamelet/progress variable (TSFPV) model is further extended and validated on the configurations of Delft spray flame AII and Sydney piloted ethanol spray flame EtF2, representing the systems with a single inlet and three inlets, respectively. The strategies for generating the spray flamelet library are adjusted, and an extended model is developed for modeling flame AII. Large eddy simulations of these two flames are conducted to evaluate the accuracy of the TSFPV model. The results of flame AII show that some droplets penetrate into the flame zone, and significant droplets/flame interactions occur. The flame exhibits a typical double flame structure. The predictions of gas phase temperature are in good agreement with the experimental measurements, which indicates that the current model can better consider the influence of droplet evaporation and the temperature reduction caused by interphase heat loss. The results of flame EtF2 also achieve good agreement with experimental data according to radial profiles of axial droplet velocities and gas phase temperature. Overall, the TSFPV model is well validated and exhibits sound performance on different flame configurations, indicating its widespread applicability and generalizability.