A flame produced without premixing of primary air with gas prior to ignition is referred to as what?

A flame produced without premixing of primary air with gas prior to ignition is referred to as a luminous flame. This type of flame occurs when there is insufficient air mixed with the fuel, causing incomplete combustion. As a result, the flame produces a yellowish light and emits soot, which indicates that carbon is not fully combusted. The presence of unburned particles in the flame gives it its luminous quality.

In contrast, a Bunsen flame typically involves the mixing of gas with air before combustion, which can produce a hotter and more efficient blue flame. A blue flame indicates complete combustion, where fuel is efficiently mixed with the right amount of air, producing less soot and a higher-temperature flame. Understanding these distinctions is crucial for gas technicians when adjusting burners for optimal performance.