What causes the condition known as 'hot streaking' in turbine engines?

Hot streaking in turbine engines is primarily caused by a partially clogged fuel nozzle. When the fuel nozzle is not delivering the correct amount of fuel consistently, it can lead to uneven combustion. This results in specific areas of the combustion chamber where the combustion temperature is significantly higher than in others. These hotter areas are what we refer to as "hot streaks."

As fuel is introduced unevenly, some regions may experience more fuel than others, leading to increased temperatures where the fuel is being more effectively combusted. The proper functioning of the fuel nozzles is vital for maintaining uniform combustion and minimizing the potential for hot streaks, which can cause damage to engine components and reduce efficiency.

In contrast, other factors such as blocked air filters, inadequate cooling, or excessive airflow do not directly lead to hot streaking the same way a clogged fuel nozzle does. A blocked air filter primarily hampers airflow into the engine, which can affect performance but not necessarily cause localized hot streaks. Inadequate cooling can lead to overall overheating but does not create hot spots in the combustion process. Excessive airflow can dilute the air-fuel mixture, but it is the flow and distribution of fuel that most directly influences the occurrence of hot streaking.