Turbomachine Diffuser Flow Mixing Lobes

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional turbomachine exhaust diffusers face inefficiencies in kinetic energy reduction and static pressure recovery due to flow separation and boundary layer growth, particularly when handling high momentum exhaust gases.

Innovation Solution

The integration of flow mixing lobes arranged in an annular array on the inner surface of the diffuser, which guide high momentum flows toward the inner surface, forming flow vortices that reduce boundary layer growth and enhance pressure recovery by directing a portion of the exhaust gases radially outward.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional diffuser geometry is used, then structural simplicity is maintained, but flow separation and boundary layer growth occur reducing pressure recovery

Engineering Contradiction:

Improvediffuser structureVSAvoidpressure recovery

Core Design Contradiction:

Device complexityVSEase of manufacture

Solution Approach 1:

The diffuser inner surface is segmented into multiple discrete flow mixing lobes arranged in an annular array, rather than using a conventional smooth surface. Each lobe acts as an independent flow control element that redirects high momentum fluid toward the surface, preventing boundary layer growth and flow separation while maintaining overall diffuser functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flow mixing lobes create localized regions of enhanced flow mixing and momentum transfer at specific positions along the diffuser inner surface. By concentrating flow control actions at these discrete locations rather than uniformly across the entire surface, the design achieves improved pressure recovery without requiring complete redesign of the entire diffuser geometry.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If high momentum exhaust gases are handled, then kinetic energy reduction is achieved, but flow separation increases reducing efficiency

Engineering Contradiction:

Improvekinetic energy reductionVSAvoidflow efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The high momentum exhaust gases, which normally cause flow separation and reduce efficiency, are redirected by the flow mixing lobes to interact with the boundary layer near the diffuser surface. This converts the harmful high momentum flow into a beneficial effect that enhances mixing, prevents separation, and improves overall flow efficiency while maintaining kinetic energy reduction.

Inventive Principle:

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

3Ease of manufacture

If flow mixing lobes are added, then pressure recovery is improved, but device complexity increases

Engineering Contradiction:

Improvepressure recoveryVSAvoiddiffuser structure

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Rather than attempting to control the entire flow field uniformly, the design applies flow mixing lobes at specific strategic positions along the diffuser. This partial action approach achieves sufficient pressure recovery improvement without requiring complete redesign of the entire diffuser structure, balancing complexity and performance.

Inventive Principle:

Principle #16Partial or excessive 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 improves pressure recovery in the exhaust diffuser, leading to enhanced system efficiency by reducing flow separation and increasing kinetic energy reduction.

Implementation Method 1

guide a substantially high momentum flow toward the inner surface of the body... forming flow vortices

Methodology Applied

Scientific EffectFlow vortex formation: Vortex Ring

Implementation Method 2

mixing the substantially high momentum flow with a boundary layer flow passing along the inner surface

Methodology Applied

Scientific EffectBoundary layer mixing: Turbulence

Implementation Method 3

The exhaust diffuser is geometrically configured to rapidly decrease the kinetic energy of flow and increase static pressure recovery within the exhaust diffuser

Methodology Applied

Scientific EffectKinetic energy to pressure conversion: Bernoulli Effect

Data Source

PatentUS10344604B2Turbomachine diffuser including flow mixing lobes and method

Publication Date: 2019.07.09 GE INFRASTRUCTURE TECH LLC

AI summary

A turbomachine diffuser includes a body having an inner surface defining a diffuser flow path, a plurality of stationary struts extending from the inner surface, and a plurality of flow mixing lobes arranged in an annular array on the inner surface. The plurality of flow mixing lobes is configured and disposed to guide a substantially high momentum flow toward the inner surface of the body.