High-Pressure Turbine Clearance Control for Takeoff Core Speed

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Solution Overview

Problem

During engine takeoff, especially on hot days, the engine core speed often exceeds the maximum allowable threshold, leading to a thrust shortfall, and reducing engine core speed by opening variable stator vanes compromises compressor stall margin, making it an undesirable 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, employing a processor and controller to adjust the clearance based on engine parameters such as core speed and exhaust gas temperature to maintain optimal performance.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:

Improveengine core speedVSAvoidcompressor stall margin

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The invention changes the control parameter from variable stator vane opening to turbine clearance control. By actively controlling the turbine clearance (a different parameter), the system achieves engine core speed reduction while avoiding the negative effects of VSV opening on compressor stall margin

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces turbine clearance as an intermediary control mechanism. Instead of directly controlling engine core speed through VSV (which has harmful side effects), the system uses turbine clearance as an intermediate variable that indirectly influences engine core speed while maintaining compressor stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Effectively reduces engine core speed by nearly 1% during takeoff without compromising compressor stall margin, ensuring safe and efficient operation by dynamically adjusting turbine clearance in response to varying conditions.

Implementation Method 1

controlling an engine turbine clearance based on the condition of the engine so as to influence the engine core speed

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11225915B2Engine core speed reducing method and system

Publication Date: 2022.01.18 GENERAL ELECTRIC CO

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.