Backdraft violence is increased by which condition of the air/fuel mixture?

Backdraft violence is increased by which condition of the air/fuel mixture?

• A. The more confined the air/fuel mixture, the more violent the backdraft.
• B. The more dispersed the air/fuel mixture, the more violent the backdraft.
• C. The more confined the air/fuel mixture, the less violent the backdraft.
• D. The more starved the air/fuel mixture, the more violent the backdraft.

Answer: (A)

Backdraft violence comes from a buildup of hot, unburned fuel gases in a closed or tightly sealed space. When air finally enters, those gases burn rapidly. The tighter the space, the less room there is for the gases to expand, so the pressure spike when ignition happens is much stronger. In a more dispersed mixture, the fuel is spread out and the ignition front isn’t as concentrated, so the blast isn’t as violent. If the mixture is starved of air, there’s not enough oxygen to drive a fast, explosive burn, also reducing the violence.

Backdraft violence comes from a buildup of hot, unburned fuel gases in a closed or tightly sealed space. When air finally enters, those gases burn rapidly. The tighter the space, the less room there is for the gases to expand, so the pressure spike when ignition happens is much stronger. In a more dispersed mixture, the fuel is spread out and the ignition front isn’t as concentrated, so the blast isn’t as violent. If the mixture is starved of air, there’s not enough oxygen to drive a fast, explosive burn, also reducing the violence.