Numerical analyses of laminar flames propagating in mono-dispersed quiescent droplet mists are addressed. Attention has been given to the evolution of combustion reactions interacting with different mists and the assessment of chemistry simplifications. In the first part, investigations are exclusively performed in a detailed description of the chemistry. Focus is concentrated on simplifications typically assumed in simulations of turbulent spray combustion. Namely, evaporative cooling and differential diffusion. These phenomena are systematically studied together with the characteristics of the observed flammability limits. In the second part, simulations conducted with the flamelet generated manifold (FGM) method are compared with detailed chemistry results. Flame propagation speed and profiles of selected quantities are used. Results demonstrate to what extent common simplifications applied to turbulent spray combustion, as well as FGM tables constructed with single-phase flamelets, are suitable for representing spray flame characteristics.
7 June 2022 in International Journal of Heat and Mass Transfer
Micro-gas turbines are a good alternative for on-site power generation, since their operation is very reliable. The possibility of operating with various fuels increases versatility and, as a result, the usage of these devices. Focusing on a performance improvement of a tri-fuel low-cost micro-gas turbine, this work presents investigations of the inner flow of its combustion chamber. The aim of this analysis was the characterization of the flame structure by the temperature field of the chamber inner flow. The chamber was fuelled with natural gas. In the current chamber, a swirler and a reversed flow configuration were utilized to provide flame stabilization. The inner flow investigations were done with numerical analysis, which were compared to experimental data. The analysis of the inner flow was done with numerical simulations, which used the RSM turbulence model. A β-PDF equilibrium model was adopted to account for the turbulent combustion process. Different models of heat transfer were compared. Thermal radiation and specially heat conduction in the liner walls played significant roles on results