Integral Heat Exchanger Mounting Arm for Thermal Expansion Relief

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Solution Overview

Problem

Heat exchangers in aircraft experience significant internal stresses and potential leakage or rupture due to operational loads causing thermal and pressure-induced growth and distortion, as existing mounting arrangements do not allow for expansion.

Innovation Solution

An additively manufactured heat exchanger design featuring a central spar and radially extending mounting arms, integrally formed via layer-by-layer additive manufacturing, which allows the heat exchanger core to grow in length and diameter while reducing strain at connection points through compliance in specific axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the mounting arrangement is rigid to maintain structural stability, then the heat exchanger experiences significant internal stresses and potential leakage during thermal expansion, but if the mounting arrangement is flexible to allow growth, then structural stability deteriorates

Engineering Contradiction:

Improveheat exchanger integrityVSAvoidinternal stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The mounting arm's geometry is modified to include compliant features that change their mechanical parameters under load. The arm transitions from a rigid structure to one that exhibits controlled flexibility through geometric design, allowing it to deform elastically under thermal expansion loads while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The mounting arm is designed as a dynamic structure that can adapt its stiffness characteristics. Through additive manufacturing, the arm incorporates varying wall thicknesses and internal geometries that allow it to be stiff under normal conditions but become more compliant during thermal expansion, enabling the system to accommodate growth without excessive stress.

Inventive Principle:

Principle #15Dynamics

2Ease of manufacture

If traditional separate-component mounting is used, then assembly is simpler, but additional components like bearings increase system weight and complexity

Engineering Contradiction:

Improveassembly simplicityVSAvoidnumber of components

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The mounting arm is integrally formed with the heat exchanger core through additive manufacturing, merging what would traditionally be separate components (heat exchanger body, mounting brackets, and fasteners) into a single monolithic structure. This eliminates the need for additional mounting components while maintaining assembly simplicity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mounting arm serves multiple functions simultaneously: it provides structural support, enables thermal expansion accommodation, and acts as an integral connection between the heat exchanger core and mounting points. This multi-functionality reduces the need for separate specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Strength

If conventional manufacturing methods are used, then production is more established, but achieving integral formation of mounting arms and heat exchanger core requires multiple assembly steps

Engineering Contradiction:

Improveintegral connection strengthVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces traditional mechanical assembly methods (separate manufacturing of components followed by assembly with fasteners or welds) with additive manufacturing technology. This enables the direct fabrication of complex integral structures that would require multiple assembly steps using conventional methods, while maintaining or improving connection strength.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The design significantly reduces stress and strain at connection points, enabling the heat exchanger to handle thermal and vibrational loads without damage, and potentially eliminates the need for additional components like bearings, reducing system weight and improving thermal performance.

Implementation Method 1

heat exchangers to grow and distort during operational loads

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

significantly reduced strain at the connection between the heat exchanger and external structure to which it is mounted

Methodology Applied

Scientific EffectStress distribution:

Data Source

PatentUS11441850B2Integral mounting arm for heat exchanger

Publication Date: 2022.09.13 HAMILTON SUNDSTRAND CORP

AI summary

A heat exchanger includes a central spar, a body, and a mounting arm. The central spar is disposed along an axial centerline of the heat exchanger. The body is disposed around the central spar. The body includes an exterior wall and heat exchanger core disposed within the exterior wall and integrally formed with the central spar. The mounting arm is integrally formed with and extends radially from the central spar. The mounting arm extends through a portion of the body and is integrally formed with the central spar via additive manufacturing.