Relative Fuel Ratio Unit Limiter for Gas Turbine Surge Recovery

A non-transitory machine-readable medium including instructions that when executed cause at least one processor to:

• monitor a fuel ratio unit (RU) of a gas turbine engine over time, wherein the RU is a ratio of a fuel flow to a compressor discharge pressure during operation of the gas turbine engine;
• store the RU in a memory;
• in response to identifying a surge detection time at which an engine surge is detected, retrieve, from the memory, a pre-surge RU before the surge detection time, wherein the pre-surge RU corresponds to a pre-surge time;
• determine a relative RU limit based on the pre-surge RU such that the relative RU limit is less than the pre-surge RU by at least a bias value;
• and
• limit the fuel flow to the relative RU limit for a duration of the detected engine surge.

An electronic device comprising:

• a memory;
• and
• at least one processor configured to:
• monitor a fuel ratio unit (RU) of a gas turbine engine over time, wherein the RU is a ratio of a fuel flow to a compressor discharge pressure during operation of the gas turbine engine;
• store the RU in the memory;
• in response to identifying a surge detection time at which an engine surge is detected, retrieve, from the memory, a pre-surge RU before the surge detection time, wherein the pre-surge RU corresponds to a pre-surge time;
• determine a relative RU limit based on the pre-surge RU such that the relative RU limit is less than the pre-surge RU by at least a bias value;
• and
• limit the fuel flow to the relative RU limit for a duration of the detected engine surge.