Turbine Clearance Control for Engine Core Speed Limits
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Solution Overview
Problem
During engine takeoff, especially on hot days, there is a challenge in controlling engine core speed within the maximum allowable threshold without reducing compressor stall margin, as opening variable stator vanes is not a desirable option.
Innovation Solution
An engine core speed reducing method and system that determines the engine's condition using sensors and controls the high pressure turbine clearance to influence the engine core speed, utilizing a processor and controller to adjust the clearance based on detected parameters such as core speed and exhaust gas temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If variable stator vanes are opened to reduce engine core speed, then engine core speed is reduced, but compressor stall margin is reduced
Solution Approach 1:
The patent changes the control parameter from variable stator vane opening to turbine clearance adjustment. By actively controlling the turbine clearance through thermal expansion mechanisms (heating or cooling turbine components), the engine core speed is reduced without affecting the compressor stall margin, as the clearance change directly impacts turbine efficiency and core speed independently of compressor airflow characteristics.
2Power
If turbine clearance is reduced to increase thrust, then thrust is increased, but engine core speed exceeds maximum allowable threshold
Solution Approach 1:
The patent implements dynamic control of turbine clearance during engine operation, particularly during takeoff. By using active clearance control systems that adjust turbine clearance in real-time based on operating conditions, the system optimizes the balance between thrust production and core speed control, allowing reduced clearance for thrust while preventing core speed from exceeding thresholds through coordinated clearance adjustment.
Data Source
AI summary
A method for reducing an engine core speed is disclosed, which includes determining a condition of an engine during operation of the engine, and controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed. An engine system comprising an engine core speed reducing system is also disclosed.