Turbine Exit Vane Water Injection for Cooler Exhaust Thrust

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Solution Overview

Problem

The increase in climb thrust and exhaust temperature during operation can be detrimental to the efficiency and operating life of gas turbine engines.

Innovation Solution

A fluid injection system is implemented to inject fluid, such as water, into the exhaust of a gas turbine engine, specifically at the turbine exit guide vanes, to reduce exhaust gas temperature and increase airflow, thereby enhancing thrust and efficiency without increasing fuel input or temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fluid is injected into the exhaust to reduce exhaust temperature, then exhaust temperature decreases and operating life increases, but thrust and efficiency may decrease due to reduced exhaust energy

Engineering Contradiction:
Improveexhaust temperatureVSAvoidthrust
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The patent utilizes the phase transition of water from liquid to vapor when injected into the hot exhaust stream. This phase change absorbs heat from the exhaust gases, effectively reducing exhaust temperature without requiring large volumes of fluid. The evaporative cooling process transforms thermal energy into phase change energy, achieving temperature reduction while maintaining exhaust flow velocity and thrust characteristics.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The system dynamically adjusts the flow rate and injection timing of the fluid based on operating conditions to optimize the balance between temperature reduction and thrust maintenance. By controlling injection parameters such as fluid quantity, injection pressure, and injection timing, the system achieves effective exhaust temperature control while minimizing negative impacts on engine performance and thrust output.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If fluid is injected into the exhaust to increase airflow, then thrust and efficiency increase, but exhaust temperature may increase due to added energy

Engineering Contradiction:
ImproveairflowVSAvoidexhaust temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The injection of fluid into the exhaust stream utilizes evaporative phase change to absorb excess thermal energy from the hot exhaust gases. This process converts thermal energy into latent heat of vaporization, effectively cooling the exhaust while simultaneously increasing the total gas volume and mass flow rate through the added fluid, thereby achieving both higher airflow and lower temperature.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The system employs hydraulic or pneumatic injection mechanisms to deliver the fluid into the exhaust stream at controlled rates and pressures. The fluid injection system utilizes pressure differentials and flow control mechanisms to ensure proper mixing and distribution of the injected fluid with the exhaust gases, maximizing cooling efficiency and airflow enhancement while minimizing temperature increase.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Power

If climb thrust is increased, then engine performance improves, but exhaust temperature increases which reduces efficiency and operating life

Engineering Contradiction:
Improveclimb thrustVSAvoidexhaust temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent converts the harmful effect of high exhaust temperature during high-power climb operations into a beneficial cooling mechanism by injecting fluid into the exhaust stream. The excess thermal energy that would otherwise damage engine components and reduce efficiency is instead utilized to drive the phase change of injected fluid, transforming a harmful thermal condition into a useful cooling process that protects the engine while maintaining high climb thrust performance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

During high-power climb operations, the system injects fluid into the hot exhaust stream where it undergoes rapid phase change from liquid to vapor. This phase transition absorbs large amounts of thermal energy from the exhaust gases, effectively reducing exhaust temperature and protecting engine components from thermal damage while allowing the engine to operate at high climb thrust levels with improved efficiency and extended operating life.

Inventive Principle:
Principle #36Phase transitions

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

The fluid injection system increases thrust and efficiency while reducing exhaust temperature, prolonging the operating life of the engine by allowing greater airflow through a constant exhaust outlet area.

Implementation Method 1

A fluid injection system is implemented to inject fluid, such as water, into the exhaust of a gas turbine engine... to reduce exhaust gas temperature and increase airflow

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3667043B1Gas turbine engine
Publication Date: 2026.03.18 RTX CORP
  • EP3667043B1 patent drawingFigure 1A
  • EP3667043B1 patent drawingFigure 1B
  • EP3667043B1 patent drawingFigure 2

AI summary

A fluid injection system (200; 300; 400) for a gas turbine engine (110) may comprise a fluid injector (160) configured to inject a fluid into an exhaust flow exiting a turbine section (28) of the gas turbine engine (110). The fluid injector (160) may be coupled to a turbine exit guide vane (150) located at a forward end of an exhaust system of the gas turbine engine (110). The fluid may decrease a temperature of the exhaust flow exiting the turbine section (28) and/or increase a thrust of the gas turbine engine (110).