Dispersed Mixtures Ignition and Combustion

Paper number

IAC-07-A2.4.07

Author

Prof. Nickolay N. Smirnov, Moscow Lomonosov State University, Russia

Coauthor

Dr. Valeriy Nikitin, Moscow Lomonosov State University, Russia

Coauthor

Mr. A.V. Kulchitsky, Moscow Lomonosov State University, Russia

Coauthor

Mrs. Valentina Nerchenko, Moscow Lomonosov State University, Russia

Coauthor

Dr. Javad Khadem, Iran

Coauthor

Dr. Shaban Alyari Shourekhdeli, Iran

Year

2007

Abstract

The problems of combustible mixtures formation and detonation initiation in pulverized in air fuels are the key aspects providing different limitations for operation of rocket and aviation engines. Onset of detonation being very dangerous for conventional engines could, however, serve the basis for creating new generation of engines - pulse detonating engines (PDE). Dispersed mixtures once having been formed under low gravity conditions could preserve their state due to absence of gravity separation.
Sensitivity of detonation onset to mixture parameters variation (size distribution function, spatial non-uniformity of dispersed phase, etc.) could be studied experimentally with a limited precision, because various modes of detonation onset depend on stochastic flow pattern created by accelerating turbulent flames thus making the transition processes non-reproducible in its detailed sequence of events. That increases the importance of numerical modeling. 
The paper presents the results of theoretical investigations of combustion and detonation initiation in heterogeneous monodisperse and polydispersed mixtures. The unsteady-state laminar flame propagation under no-gravity conditions in a mono-disperse mixture of a gaseous oxidizer with droplets of a liquid fuel was investigated. The results obtained during our theoretical study of the model were compared with experiments made in microgravity. 
The problems of fuel droplets atomization, evaporation and combustion being the key factors for ignition delays and shock waves attenuation evaluation in heterogeneous mixtures and the non-equilibrium effects in droplets atomization and phase transitions were taken into account. The effects of droplets size non-uniformity and spatial distribution non-uniformity on mixture ignition and flame acceleration were investigated. Russian Foundation for Basic Research (Project code 06-08-00029) and ISTC (2992) are acknowledged for financial support.

Abstract document

IAC-07-A2.4.07.pdf

Manuscript document

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