Gas turbine swirl angle || Combustion Spread

The swirl angle in gas turbines is a critical parameter for identifying and analyzing the fuel spray characteristics and combustion performance. It plays a significant role in controlling the air-fuel mixing process, combustion efficiency, and emissions in a gas turbine system. Below is a detailed overview of its relevance.
The swirl angle refers to the angular velocity or rotational motion imparted to the airflow in the combustion chamber of a gas turbine. This rotational motion is introduced by swirl vanes, nozzles, or other flow manipulation devices upstream of the combustion zone.
Importance in Spray Spread Identification

Air-Fuel Mixing:

The swirl angle significantly influences the air-fuel mixing process. A higher swirl angle increases the mixing intensity, leading to finer atomization and better combustion efficiency. Lower swirl angles, on the other hand, result in less turbulence and potentially poorer mixing.
Spray Spread and Distribution:

The angle directly affects the cone-shaped spray pattern of the fuel as it exits the nozzle. A high swirl angle produces a wider cone, while a low swirl angle creates a narrower spread.
This helps engineers determine the fuel distribution pattern and whether it meets the design requirements for efficient combustion.
Flame Stabilization:

A controlled swirl ensures the flame remains anchored within the combustion zone, promoting stable combustion. If the swirl angle is inappropriate, it can lead to flame blowout or combustion instability.
Emission Control:

Proper swirl management minimizes the formation of unburnt hydrocarbons (UHC), carbon monoxide (CO), and nitrogen oxides (NOx). Excessive or insufficient swirl can lead to incomplete combustion, increasing emissions.