Atomizing Fuel Nozzle with Segmented Air and Fuel Passages

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Solution Overview

Problem

Designing and manufacturing fuel nozzles for small gas turbine engines is challenging due to space constraints, especially for hybrid nozzles where air and fuel conduits must cross each other at the nozzle tip to achieve the desired spray angle, requiring precise alignment and minimal wall thicknesses and conduit sizes.

Innovation Solution

The fuel nozzle design features an annular body with radially oriented air passages and axially oriented fuel passages, where air passages are circumferentially spaced apart and fuel passages are positioned between them, allowing for efficient mixing and combustion while easing manufacturing and maintenance by positioning the crossing passages at the upstream end rather than the tip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If air and fuel conduits cross at the nozzle tip to achieve desired spray angle, then spray performance is improved, but manufacturing precision and assembly difficulty increase due to minimal wall thickness requirements

Engineering Contradiction:

Improvespray performanceVSAvoidconduit alignment precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The nozzle is divided into distinct functional sections: the body with air passages, the insert with fuel passages, and the tip. This segmentation allows each component to be manufactured and assembled separately, reducing the precision requirements for the entire assembly while maintaining spray performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insert component is introduced as an intermediary element between the body and tip. This insert contains the fuel passages and provides a mounting surface for the tip, serving as a mediator that simplifies the overall structure and reduces manufacturing complexity while enabling the necessary conduit crossings.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If conduit sizes and wall thicknesses are minimized to fit space constraints, then space utilization is improved, but structural strength and heat insulation deteriorate

Engineering Contradiction:

Improvenozzle volumeVSAvoidconduit wall strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

By segmenting the nozzle into body, insert, and tip components, each with optimized wall thicknesses for their specific functions, the design achieves both compact volume and adequate structural strength without requiring excessive wall thickness throughout the entire nozzle.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the nozzle have different wall thicknesses optimized for their local requirements: the body has sufficient thickness for structural support, while the insert and tip are minimized for space constraints, achieving local optimization of both strength and volume.

Inventive Principle:

Principle #3Local quality

3Device complexity

If air and fuel passages are closely grouped to achieve compact design, then device complexity is reduced, but heat insulation between passages deteriorates

Engineering Contradiction:

Improvepassage arrangement complexityVSAvoidheat transfer between passages

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The insert acts as a thermal barrier and intermediary structure between the air passages in the body and the fuel passages in the tip, providing heat insulation while maintaining the compact grouped arrangement of passages.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insert provides localized heat insulation at the interface between air and fuel passages, allowing the passages to be closely grouped for compactness while preventing harmful heat transfer through the insert material.

Inventive Principle:

Principle #3Local quality

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 design ensures efficient combustion by creating a fine mist of air and fuel, improves manufacturing and maintenance ease by providing greater tolerance and heat insulation, and reduces the complexity of designing within constrained spaces.

Implementation Method 1

Atomizing fuel nozzle... an airblast nozzle... conveying air through the body toward the nozzle center axis and into the central air passageway... conveying fuel through the nozzle via fuel passages... the fuel and air mixing together to produce the air and fuel mixture

Methodology Applied

Scientific EffectAtomization:

Implementation Method 2

the fuel exiting the fuel passage outlets downstream of the air exiting the air passage outlets, the fuel and air mixing together to produce the air and fuel mixture

Methodology Applied

Scientific EffectFluid mixing:

Data Source

PatentUS10184403B2Atomizing fuel nozzle

Publication Date: 2019.01.22 PRATT & WHITNEY CANADA CORP

AI summary

A fuel nozzle for a gas turbine engine. The nozzle has a body and a center axis. The body has an inner circumferential surface circumscribing a central passageway which is coaxial with the center axis. The nozzle also has air passages which extend predominantly radially inward through the body. The air passage outlets of each air passage are circumferentially spaced apart from one another along the inner circumferential surface. Each air passage conveys air through the body toward the nozzle center axis and into the central passageway. The nozzle also has fuel passages which extend through the body. Each fuel passage is disposed within the body between adjacent circumferentially spaced apart air passages and is transverse to the direction of extension of its neighboring air passages.