Effect of Initial Conditions and Numerical Investigation of Instability Developed during Synthesis of TiC via Vortex Combustion at Moderate Temperatures. Model of Vortex Combustion

Despite the fact that the classical theory of combustion (CTC) operates with the simplest, elementary objects and concepts, such as: flat or slightly curved combustion fronts, elementary combustion models and potential flows. there are some problems that the CTC is only facing with a sufficiently strong curvature of the front. For example, Markstein's solution in the problem of hydrodynamic instability of a plane combustion front. In the work presented by the authors, the problem of stabilizing the titanium carbide synthesis front at moderate temperatures, which cannot be plane due to the thermo physical features of the system under consideration (Le<<1, Ze=6.03 at Тad=3300К), is similarly solved. A model of vortex combustion with a spirally curved front is proposed, the numerical analysis of which showed the stability of similar front of the TiC synthesis in the field of vortex hydrodynamic currents. The resulting solution can serve as a complete alternative to the mode of spiral spin combustion (or rather, to its branch with a low orbital speed and a low combustion temperature) of such systems, not only considered conditionally unstable in CTC, but also actually manifesting this instability during numerical calculations of the area of the existence of a spinal spot with a small radius and great curvature.

Excess Enthalpy Flames

Combustion processes with excess enthalpy are described with examples given. It is shown that different processes, such as heat and mass transfer, phase and chemical changes are involved. Moreover, flames with excess enthalpy can be encountered in a variety of forms such as laminar or turbulent, within homogeneous or heterogeneous systems involving stationary or unsteady processes, with pulse or spin combustion and as cellular flames. It is to be shown that mainly due to the increase in the chemical reaction rates within the combustion zone, the excess enthalpy state can lead to substantial increases in the burning rates, widening the associated flammability limits and modifying the preignition processes. Some applications that can benefit from the use of such flames are outlined.