Flow Conditioner Screen Holes Dampen Combustion Pressure Fluctuations

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Solution Overview

Problem

Acoustic pressure fluctuations in combustion systems, such as industrial gas turbines, can cause structural damage by exciting natural frequencies, and existing solutions like redesigning hardware or adding external resonators are costly and reduce combustion efficiency.

Innovation Solution

A flow conditioner with screen holes tuned to specific frequencies is placed in the air path of the combustor to dampen pressure fluctuations, using existing hardware and avoiding the need for external resonators by leveraging friction and pressure drops to suppress acoustic pressure fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If external resonators are added to dampen pressure fluctuations, then acoustic pressure fluctuations are reduced, but combustion efficiency decreases due to air diversion

Engineering Contradiction:

Improveacoustic pressure fluctuationsVSAvoidcombustion efficiency

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The flow conditioner merges the damping function with the existing air path structure by installing screen holes directly in the air path, eliminating the need for separate external resonators. This integration allows the same air flow to serve both combustion and damping purposes without air diversion, resolving the contradiction between reducing acoustic pressure fluctuations and maintaining combustion efficiency

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The screen holes act as an intermediary element in the air path that dissipates acoustic energy through friction and pressure drops without requiring separate damping air supplies. This intermediary structure enables pressure fluctuation reduction while maintaining the primary air flow for combustion, avoiding the efficiency loss associated with external resonators

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If hardware is redesigned to prevent natural frequency excitation, then acoustic pressure fluctuations are reduced, but system cost increases due to extensive testing and modifications

Engineering Contradiction:

Improveacoustic pressure fluctuationsVSAvoidsystem cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

Rather than redesigning the entire hardware system, the invention segments the problem by adding a specific damping component (flow conditioner with screen holes) to the air path. This localized modification targets the acoustic pressure fluctuation issue without requiring extensive hardware redesign and testing, reducing development costs while effectively reducing acoustic pressure fluctuations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the physical parameters of the air path by introducing screen holes with specific hole sizes, densities, and configurations. These parameter modifications enable acoustic damping without requiring fundamental hardware redesign, avoiding the extensive testing and modification costs associated with complete system redesign

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If air is diverted to external resonators for damping, then pressure fluctuations are reduced, but combustion performance decreases due to reduced air availability

Engineering Contradiction:

Improvepressure fluctuationsVSAvoidcombustion performance

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The air path itself serves the dual function of supplying combustion air and providing acoustic damping through the screen holes. The air flow that would otherwise only serve combustion now also performs the damping function self-service style, eliminating the need for separate damping air supplies and maintaining combustion performance

Inventive Principle:

Principle #25Self-service

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 acoustic pressure fluctuations across a wide range of frequencies, extending the life and performance of the combustion system without diverting air or altering hardware design, thus maintaining efficiency and reducing costs.

Implementation Method 1

leveraging friction and pressure drops to suppress acoustic pressure fluctuations

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

leveraging friction and pressure drops to suppress acoustic pressure fluctuations

Methodology Applied

Scientific EffectPressure Drop: Pressure Drop

Implementation Method 3

dampen pressure fluctuation caused by combustion dynamics

Methodology Applied

Scientific EffectAcoustic Absorption: Acoustic Absorption

Data Source

PatentUS10663170B2Flow conditioner to reduce combustion dynamics in a combustion system

Publication Date: 2020.05.26 DOOSAN HEAVY IND & CONSTR CO LTD

AI summary

A flow conditioner in a combustor of a gas turbine comprises a body and a flow conditioning portion configured to be placed in an air path providing air flow to a combustion chamber, the flow conditioning portion including a plurality of holes tuned to a damping frequency to dampen a pressure fluctuation caused by combustion dynamics from the combustion chamber.