HAM Explosion in Semi-confined Duct

HAM combustion behavior greatly depends on the configuration of a volume filled with a combustible mixture. Let us analyze the experimental data obtained in a semi-confined U-shaped duct [11-13], the general view is shown in Fig. 9.22. The HAM contained 37 1% H2 at normal temperature and pressure conditions in these experiments. Three typical cases were distinguished  

In the first case, the flame acceleration to 170 m/s was recorded only when the flame reached the open part of the duct as a result of the mixture jet pushed out by the combustion front. The recorded pressure perturbation level was up to 15 kPa. 

In the second case the 1.5 m fan installed near the initiator significantly changed the blast dynamics. The fan maximum efficiency (24,000 m /h) was rarely used in the experiments. 

When the flame advanced in the vicinity of the fan (3) the deflagration (2) accelerated to 200 m/s and a pressure wave up to 40 kPa amplitude was radiated 

In the third case the explosion exited from a pre-combustion chamber HAM with 19.9-22.5% H2 content was studied. The DDT process was recorded in experiments with more than 20.8% H2 content independently on the control port square area. As a rule, the DDT processes are initiated in areas of the pressure wave focusing ahead of the combustion zone. 

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