Mild Combustion. Una lezione nell'atelier di un "nuovo" processo di combustione

Mild Combustion is a process completely different both from deflagration, detonation, explosion in a classic form, and also from the processes that generate diffusion flames. Therefore it deserves to be analyzed separately from these processes and quoted with a specific name. The name proposed by the authors and used in the recent literature is "Mild" Combustion when the process refers to maximum, frozen and auto-ignition temperatures, which are combined in such a way that the mixture can auto-ignite and yield a relatively small temperature increase comparable to the difference between the ignition and standard temperature. This is a broad definition that could be specified in several processes in homogeneous mixture named HBBIHomogeneous Burnt Backmixing Ignition HCCIHomogeneous Charge Compression Ignition HFFIHomogeneous Flow Flowing Ignition as well as in a system with separated reactants named HDDIHot Diluted Diffusion Ignition Although specification and dominions where these processes exist have to be further investigated in order to give a clearer and narrower definition of each of them, the main characteristics of Mild Combustion are well identified. -This is a process that does not yield a double state (frozen and burnt) differently from the classic combustion processes. It develops in a single possible mode, and therefore it does not produce noise coupled to ignition and extinction. -This is a process that develops in a wide temporal range for homogeneous systems and in a wide mixture fraction range for separate reactants systems. Therefore it makes the processes more homogeneously distributed. These characteristics and others are analyzed in the paper for each of the possible Mild Combustion processes. In particular the Hot Diluted Diffusion Ignition process is analyzed deeply for all possible combinations of the boundary conditions in terms of temperature and dilution on the ground of the oxidation process in counter-diffusion flows. Finally these results are used to investigate the characteristics of complex processes, where the Mild Combustion conditions are created in some parts of them, as well as the potentials of the process in different technological fields.