What is the phenomenon called when a flame unexpectedly goes out while creating a popping sound?

The phenomenon where a flame unexpectedly goes out while making a popping sound is referred to as a flameout. A flameout occurs when the combustion process in a flame is disrupted, leading to the combustion ceasing abruptly. This can happen due to several factors, such as a reduction in fuel supply, interruption in the air supply, or a sudden change in temperature or pressure within the combustor. The popping sound associated with a flameout is often a result of unburned fuel igniting rapidly when the conditions stabilize, causing a sudden release of energy.

In contrast, a backfire typically refers to a situation where combustion occurs in the intake or exhaust system of an engine, which does not directly correspond to the scenario described. A flashback is when a flame travels back into the fuel supply line, which is also not aligned with the characteristics of a flameout. Fireback is not a commonly recognized term in fire science or safety contexts. Therefore, flameout is the most accurate term for the phenomenon described.