Pulsating Diffusion Flames Fed With Biomass Particles In Counter-Flow Arrangement: Zeldovich And Lewis Numbers Effects

Natural and forced instabilities have a significant influence on the performance and efficiency of biomass-fueled combustion systems, where oscillatory behaviors cannot be ignored. This work concentrated on the analytical modeling of pulsating biomass-fueled diffusion flames in the non-premixed counter-flow arrangement, accounting for the effects of Lewis and Zeldovich numbers. Preheating, post-vaporization, reaction, and oxidizer zones were considered in the model derivation. In order to model the oscillatory characteristics, oscillations were mathematically modeled using a sinusoidal function. Transient mass and energy balance equations were formulated and analytically solved considering different Lewis and Zeldovich numbers. To preserve continuity and obtain the flame front position, jump conditions were given. After validating the derived analytical model, transient characteristics of flame temperature and position and time-varying distributions of reactants temperature and mass fraction were presented under pulsating conditions. Results show that Lewis number is the main parameter controlling the oscillatory and pulsating behaviors of the flame. Furthermore, Zeldovich number seems to escalate the effects of Lewis number.