What causes flames to lift off of a burner and maintain their shape?

The phenomenon of flames lifting off a burner and maintaining their shape is primarily caused by excessive gas pressure or an imbalance in the primary air supply. When there is too much gas pressure, the fuel-air mixture becomes more turbulent, which can cause the flames to be projected upward away from the burner. This can also lead to a richer mixture of gas and air burning at the burner itself, creating a larger, more defined flame pattern.

Primary air plays a crucial role in the combustion process. If the air-to-fuel ratio is not optimal—namely, if there's an excess of gas relative to the amount of air—that can lead to incomplete combustion, creating a lift in the flames. Additionally, proper combustion requires a certain balance; too little air leads to issues such as poor burning efficiency, but too much gas with insufficient air can create instability in flame shape and position.

This understanding of flame behavior is critical for diagnosing and adjusting commercial gas equipment to ensure safe and efficient operation. In contrast, lower gas pressure, insufficient fuel supply, or high humidity do not contribute to lifting flames in the same way. Low gas pressure would typically lead to weak flames, insufficient fuel supply could extinguish flames or reduce their intensity, and high humidity primarily affects the combustion efficiency and