Helical Inner Tubes in Gas Turbine Fluid Coolers

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Solution Overview

Problem

Existing fluid coolers for gas turbine engines face challenges in increasing heat transfer efficiency while minimizing size and weight, which are critical for airborne applications, as longer tubes required for enhanced heat transfer often lead to increased size and weight, necessitating additional mounting hardware.

Innovation Solution

The design incorporates a helically extending outer tube with varying pitch and taper angles of inner tubes, which increases the effective length of the fluid cooler without increasing its overall length, enhancing heat transfer efficiency while maintaining a compact form factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the effective length of the tubes is increased to increase the surface area for heat transfer, then heat transfer efficiency is improved, but the size and weight of the fluid cooler increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidweight of fluid cooler
Core Design Contradiction:
Use of energy by moving objectVSWeight of stationary object

Solution Approach 1:

The patent transitions from straight tubes to helical coils, changing the spatial dimension of tube arrangement. This allows the tubes to extend longer in a compact volume by utilizing three-dimensional space more effectively, increasing heat transfer surface area without proportionally increasing the overall cooler size or weight.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The helical tubes are nested within the cylindrical casing of the fluid cooler, with multiple tube passes arranged concentrically. This nesting approach maximizes the use of internal volume, allowing long tube length within a compact external dimensions, thereby improving heat transfer efficiency without increasing weight.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Use of energy by moving object

If the effective length of the tubes is increased to increase the surface area for heat transfer, then heat transfer efficiency is improved, but the size of the fluid cooler increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidsize of fluid cooler
Core Design Contradiction:
Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

By configuring tubes as helical coils rather than straight lines, the patent utilizes three-dimensional rotational space within the cylindrical casing. This allows the tubes to achieve greater effective length within the same external volume, improving heat transfer surface area without increasing the overall size of the fluid cooler.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The helical curvature of the tubes allows them to wrap around the internal volume of the casing, maximizing the use of available space. This curved configuration enables longer tube length within a compact cylindrical form factor, improving heat transfer efficiency without increasing the external dimensions of the cooler.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If the weight of the fluid cooler is increased to support additional mounting hardware, then structural support is improved, but the overall weight and complexity increase

Engineering Contradiction:
Improvestructural supportVSAvoidmounting hardware requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent integrates mounting features directly into the tube structure itself, combining the structural support function with the heat transfer component. The tubes are designed with built-in mounting capabilities, eliminating the need for separate mounting hardware and reducing overall structural complexity while maintaining adequate support.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The tube structure serves multiple functions: heat transfer, structural support, and mounting. By designing the tubes to be both thermally efficient and mechanically robust, the patent eliminates the need for additional dedicated mounting components, reducing device complexity while maintaining structural integrity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances heat transfer efficiency by increasing the effective length of the inner tubes without increasing the fluid cooler's size or weight, allowing for more effective cooling with reduced mounting hardware requirements, thus addressing the need for compact and lightweight solutions in gas turbine engines.

Implementation Method 1

fluid coolers and heat exchangers are used in various locations in gas turbine engines to transfer heat between two or more fluids

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

heat transfer between the fluids may occur

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4047296B1Gas turbine engine with a fluid cooler
Publication Date: 2024.09.18 PRATT & WHITNEY CANADA CORP
  • EP4047296B1 patent drawingFigure 1
  • EP4047296B1 patent drawingFigure 2
  • EP4047296B1 patent drawingFigure 3A

AI summary

A fluid cooler (30) for a gas turbine engine (10) includes an outer tube (32) having an outer tube inlet (40) at a first end (36) of the fluid cooler and an outer tube outlet (42) at a second end (38) of the fluid cooler (30). A primary axis (48) of the fluid cooler (30) is defined within the outer tube (32) between the first and second ends (36, 38) of the fluid cooler (30). A plurality of inner tubes (34) extend within the outer tube (32) between the first second ends (36, 38) of the fluid cooler (30). The inner tubes (34) have a common inner tube inlet (50) and a common inner tube outlet (52). The inner tubes (34) extend helically about the primary axis (48). A first group of the inner tubes (34) are disposed at a first radius (R1) from the primary axis (48) and a second group of the inner tubes (34) are disposed at a second radius (R2) from the primary axis (48), the second radius (R2) different from the first radius (R1).