Concentric Mixing Nozzle for Aircraft Fuel Tank Inerting

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Solution Overview

Problem

Conventional fuel tank inerting systems face challenges in achieving effective oxygen reduction in aircraft fuel tanks, necessitating improved inerting systems that can efficiently mix and vaporize fuel under arduous flight conditions while maintaining low pressure loss and contamination resistance.

Innovation Solution

The proposed solution involves a nozzle assembly with an outer gas flow path, an inner gas flow path, and a liquid flow path, featuring a core conduit and swirl vanes, which creates a mixing zone with an air-to-liquid ratio of 400:1, ensuring efficient fuel mixing and vaporization with minimal pressure drop and contamination resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional fuel tank inerting systems are used, then oxygen reduction is achieved, but mixing efficiency and vaporization performance are insufficient under arduous flight conditions

Engineering Contradiction:

Improvemixing efficiencyVSAvoidinerting performance under flight conditions

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The gas flow path is divided into outer and inner concentric pathways, allowing separate control of gas flow regions. The liquid flow path is segmented into multiple injection zones through distributors positioned at different locations, enabling staged mixing and vaporization processes that improve overall efficiency while maintaining reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the nozzle are designed with specialized functions: the outer gas flow path handles bulk gas flow, the inner gas flow path provides concentrated mixing, liquid distributors create localized vaporization zones, and the core conduit delivers precise fuel injection. This local optimization ensures high mixing efficiency while maintaining reliable inerting performance

Inventive Principle:

Principle #3Local quality

2Productivity

If fuel mixing and vaporization are enhanced, then inerting performance improves, but pressure loss increases

Engineering Contradiction:

Improvevaporization efficiencyVSAvoidpressure loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The nozzle design incorporates dynamic flow control through the interaction of gas and liquid phases in the mixing zone. The converging outer gas flow path and diverging inner gas flow path create dynamic pressure and velocity distributions that enhance vaporization without requiring excessive pressure input, thereby improving vaporization efficiency while controlling pressure loss

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system utilizes changes in pressure, temperature, and velocity parameters as gas and liquid flows interact in the mixing zone. The metering flow lip and annular openings are designed to create controlled parameter transitions that maximize vaporization efficiency while minimizing energy loss through optimized flow dynamics

Inventive Principle:

Principle #35Parameter changes

3Productivity

If mixing zone intensity is increased, then fuel vaporization improves, but contamination resistance decreases

Engineering Contradiction:

Improvemixing intensityVSAvoidcontamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The outer gas flow path acts as an intermediary that protects the inner mixing zone from external contamination. The concentric structure allows the outer pathway to handle potential contaminants while the inner pathway maintains a controlled environment for efficient mixing and vaporization, thus enabling high mixing intensity while maintaining contamination resistance

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables efficient fuel mixing and vaporization at low flow rates, maintaining low system pressure loss and contamination resistance, effectively reducing oxygen levels in the fuel tank ullage, thereby enhancing the inerting system's performance under challenging flight conditions.

Implementation Method 1

efficient fuel mixing and vaporization

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

mixing zone with an air-to-liquid ratio of 400:1

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

swirl vanes extending therefrom

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 4

efficient fuel mixing

Methodology Applied

Scientific EffectTurbulence: Turbulence

Data Source

PatentEP4206451A1Mixing nozzle for a catalytic fuel tank inerting system for an aircraft

Publication Date: 2023.07.05 COLLINS ENGINE NOZZLES INC

Figure 1~2A
Figure 2B~2C
Figure 3

AI summary

A nozzle (101) includes an outer gas flow path (128), an inner gas flow path (130) radially inward from the outer gas flow path, a liquid flow path (132) defined radially between the inner gas flow path and the outer air flow path, and a core conduit (134) defined radially inward from the inner gas flow path. An injector assembly (104) includes an outer housing (112), a nozzle (101) within the outer housing, and an outer housing gas flow path (114) defined radially outward from the nozzle between an inner surface (116) of the outer housing and an outer surface (118) of the nozzle. The nozzle includes an outer gas flow path (128), an inner gas flow path (130) radially inward from the outer gas flow path, a liquid flow path (132) defined radially between the inner gas flow path and the outer gas flow path and a core conduit (134) defined radially inward from the inner gas flow path.