1. Kakutkina N.A., Korzhavin A.A., Rychkov A.D. Ignition of the waves of filtration gas combustion with open flame Institute of chemical kinetics and combustion SB RAS, Novosibirsk, Russia Institute of computational technologies SB RAS, Novosibirsk, Russia

2. FILTRATION GAS COMBUSTION (FGC) Steady-state FGC waves are well known: Steady-state FGC regimes Mechanisms of wave propagation at different regimes Parametric dependencies of u and T Nature of combustion limits Mathematical models of FGC

3. Nonsteady-state regimes of FGC FGC wave ignition FGC wave quenching FGC wave propagation in nonsteady-state parametric condition The object of the work is numerical study of FGC wave ignition with open flame

4. Experimental set up 1 2 3 4 5 6 8 9 10 11 7

5. Modeling system u0u0 Fresh gas Combustion products u0u0 Fresh gas Combustion products u0u0 Свежий газ Combustion products a c b

6. Mathematical model

7. Modeling results

8. Trajectory of combustion wave propagation Evolution of temperature profiles of porous medium under filtration combustion Modeling results

9. Ignition of FGC wave Temperature profiles of gas (thin lines) and porous medium (thick lines) in the stage of combustion wave formation in porous body. Time from ignition moment: 0.1 s (1), 5 s (2), then in minutes 0.5 (3), 1.5 (4), 4.5 (5),5 (6), 5.5 (7), 6 (8). Velocity of gas flow 0.24 m/s. Dashed line shows right boundary of porous body.

10. Effect of thermal conductivity of porous body on time of FGC wave ignition

11. Dependencies of time of FGC wave ignition on gas velocity h=75 mm, s=70 W/(m  К), d, mm: 3.3 (1), 2.7 (2), 2 (3).

12. Dependencies of time of FGC wave ignition in porous body on body length s, W/(m  К): 1 (1), 20 (2), 100 (3).

13. Dependencies of critical length (1) and maximum heating up of porous body (2) on channel diameter s=70 W/(m  К), v 0 =22 cm/s

14. Trajectories of flame entering and propagation in porous body with different layers at right boundary of porous body 1 – without layer, 2 – metal grid with  g =0.8, 3 – the same, but with  g =0.7, 4 – perforated metal plate with  g =0.2. Gas velocity 0.3 m/s. Dashed lines show layer position.

15. Conclusions 1.Mathematical modeling of FGC wave ignition in porous body with open flame was carried out. Mechanisms acting at FGC wave formation was revealed. 2.Dependencies of ignition time were established on thermal conductivity of porous body, filtration gas velocity, porous body length. Existence of critical conditions for FGC wave ignition was shown. 3.Methods of influence on the time of FGC wave ignition are considered.