Compressor Bleed Air Slot for Gas Turbine Efficiency

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Solution Overview

Problem

Gas turbine engines face inefficiencies due to the increased demand for cooling airflow from the compressor section, which reduces overall engine efficiency and compressor performance, particularly because of restrictions in existing cooling airflow passages.

Innovation Solution

The design incorporates a bleed air slot within the compressor section with a radially increasing inlet and outlet area, optimized for efficient airflow diffusion and reduced aerodynamic losses, allowing for improved communication of cooling airflow to the turbine section, thereby minimizing the need for additional cooling air from the compressor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling airflow passages are restricted, then turbine section cooling is maintained, but compressor efficiency and overall engine efficiency decrease due to increased cooling air demand

Engineering Contradiction:
Improveturbine cooling effectivenessVSAvoidengine efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the geometric parameters of the cooling airflow passages, specifically increasing the passage cross-sectional area and optimizing the bleed air slot dimensions (inlet area A1, outlet area A2, and length L). These parameter changes reduce flow restrictions while maintaining cooling effectiveness, thereby resolving the contradiction between reliable turbine cooling and engine efficiency.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If cooling airflow passages are expanded to reduce restrictions, then engine efficiency improves, but turbine section cooling effectiveness may be compromised

Engineering Contradiction:
Improveengine efficiencyVSAvoidturbine cooling effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by creating non-uniform distribution of cooling airflow through strategically positioned bleed air slots with specific area ratios (A2/A1) at different locations in the compressor section. This allows optimized cooling delivery to the turbine section while minimizing overall air extraction from the compressor, thus improving efficiency without compromising cooling reliability.

Inventive Principle:
Principle #3Local quality

3Reliability

If more cooling air is drawn from the compressor, then turbine section cooling is enhanced, but compressor efficiency decreases

Engineering Contradiction:
Improveturbine coolingVSAvoidcompressor efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements preliminary action by pre-cooling the compressor discharge air through the optimized cooling passages before it enters the turbine section. This preliminary cooling action reduces the temperature of the air requiring to be extracted from the compressor, thereby reducing the total amount of cooling air needed and preserving compressor efficiency while ensuring adequate turbine cooling.

Inventive Principle:
Principle #10Preliminary action

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

This configuration enhances compressor efficiency and overall engine efficiency by reducing the amount of cooling air required, leading to improved power transfer and reduced thermal losses.

Implementation Method 1

Air flow drawn from the compressor increases the efficiency of the compressor section

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

optimized for efficient airflow diffusion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2917508B1Gas turbine engine with a compressor bleed air slot
Publication Date: 2019.11.27 UNITED TECH CORP
  • EP2917508B1 patent drawingFigure 1
  • EP2917508B1 patent drawingFigure 2
  • EP2917508B1 patent drawingFigure 3~4

AI summary

A disclosed gas turbine engine includes a case for a case for a compressor section including a bleed air slot. The bleed air slot includes an inlet having a first area radially inward of an outlet having a second area with the second area being greater than the first area. The bleed air slot further includes a center portion disposed along a radial line extending from an axis of the engine and an elongated portion extending from the opening at an angle relative to a line normal to the radial line.