Practical Application of Investigation Data for Self-Ignition Processes

13 Practical Application of Investigation Data for Self-Ignition Processes 

The diagram of critical conditions for blast generation at shock wave focusing (see Fig. 6.28) can be considered as a practical result of the investigations. 

In a space without reflectors, the minimum Mach number of a shock wave capable of triggering self-ignition is about M 2. Non-planar surfaces significantly 

For the case of a duct with a combustible mixture 1 with a cone end reflector 2 (Fig. 6.29) and an obstructed area 3 creating conditions for flame acceleration, three scenarios of blast development can be anticipated (Fig. 6.30). In the first regime, at more than 20% H2 concentration in air, the igniter 4 triggers a self sustained detonation wave QS in area 3. The cone end does not affect the load on the duct. 

At less than 11 % H2 concentration in air, the flame FFl decelerates when leaving area 3, and the emitted pressure wave intensity goes to the first parameter zone (i) in Fig. 6.28 (regime III, Fig. 6.29). Again, the shaped end of the duct does not affect the blast load values. 

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