Gas Turbine Combustor Pilot Nozzle Cooling Control

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Solution Overview

Problem

In conventional gas turbine combustors, the circulating flow of high-temperature gas becomes unstable due to varying fuel injection amounts from main and pilot nozzles, leading to increased NOx generation, flame instability, and potential nozzle tip damage.

Innovation Solution

A gas turbine combustor with an injection nozzle that injects fuel and cooling air, an air flow-rate adjustment unit, and a detection unit to control the cooling air flow rate based on combustion state detection, ensuring a stable circulating flow and reducing NOx generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the circulating flow approaches the pilot nozzle, then the flame holding property is improved, but the temperature around the pilot nozzle increases causing burn damage and increased NOx generation

Engineering Contradiction:

Improveflame holding propertyVSAvoidburn damage and NOx generation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Cooling air is supplied to the pilot nozzle in advance before the circulating flow reaches it, creating a protective cooling effect that prevents burn damage and NOx generation while allowing the circulating flow to maintain its position for good flame holding

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Cooling air acts as an intermediary substance between the high-temperature circulating flow and the pilot nozzle, absorbing heat and preventing direct thermal contact that would cause burn damage and excessive NOx formation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the circulating flow moves away from the pilot nozzle, then the temperature around the pilot nozzle decreases, but the flame holding property deteriorates and combustion becomes unstable

Engineering Contradiction:

Improvetemperature around pilot nozzleVSAvoidcombustion stability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Cooling air is supplied in advance to establish a protective thermal barrier before the circulating flow moves away, ensuring that even at reduced flow rates, the flame holding property is maintained while keeping temperatures controlled

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the fuel injection amount changes, then the gas turbine output is adjusted, but the forming position of the circulating flow becomes unstable

Engineering Contradiction:

Improvegas turbine outputVSAvoidcirculating flow position

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The cooling air supply amount is adjusted based on the fuel injection amount, creating a feedback control system that maintains stable circulating flow position while allowing gas turbine output to vary according to demand

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

By changing the cooling air flow rate parameter in response to fuel injection changes, the system compensates for disturbances and maintains stable circulating flow formation position while adjusting overall output

Inventive Principle:

Principle #35Parameter changes

4Object-affected harmful factors

If cooling air is injected from the pilot nozzle, then the temperature around the pilot nozzle is reduced, but the circulating flow position becomes unstable

Engineering Contradiction:

Improvetemperature around pilot nozzleVSAvoidcirculating flow position

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The cooling air flow rate is dynamically adjusted as a controllable parameter to achieve optimal balance between temperature reduction and circulating flow stability, preventing both burn damage and position instability

Inventive Principle:

Principle #35Parameter changes

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 solution stabilizes the circulating flow, maintains flame holding properties, and prevents nozzle tip damage by adjusting cooling air flow rates, thereby improving combustion stability and reducing NOx and CO emissions.

Implementation Method 1

Cooling air is injected to the circulating flow from the pilot nozzle... the temperature around the pilot nozzle including the pilot nozzle increases

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

circulating flow of high-temperature gas flows into a space opposite to a nozzle tip... high-temperature and high-pressure combustion gas

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

The combustor supplies fuel to the compressed air to burn the fuel, thereby acquiring high-temperature and high-pressure combustion gas

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10718522B2Gas turbine combustor, gas turbine, control device, and control method

Publication Date: 2020.07.21 MITSUBISHI POWER LTD

AI summary

To provide a gas turbine combustor that can suppress a generation amount of NOx and maintain a flame holding property, while suppressing burn damage around a pilot nozzle including the pilot nozzle. A gas turbine combustor includes a pilot nozzle that can inject fuel F and cooling air A for cooling a nozzle tip, a flow regulating valve that can adjust a flow rate of cooling air to be supplied to the pilot nozzle, a detection sensor that detects a combustion state of fuel, and a control device that controls the flow regulating valve based on a detection result of the detection sensor.