Cold Chassis Cooling Ribs With Microchannels For High-Power Electronics

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Solution Overview

Problem

Existing edge cooling technologies for high-power electronic systems face challenges in scaling thermal management due to constrained geometries, clogged microchannels during brazing, and high costs associated with large-scale manufacturing, limiting their effectiveness in cooling large electronic assemblies.

Innovation Solution

The use of cooling ribs with microchannels and phase change coolants, combined with friction stir welding to secure the ribs to a frame member, allows for increased heat transfer coefficients and isothermal cooling, enabling scalable and cost-effective high-performance edge cooling solutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If microchannel heat sinks are used for high-performance cooling, then heat transfer efficiency is improved, but manufacturing complexity and cost increase due to brazing requirements and limited autoclave availability

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling system is divided into modular rib sections that can be manufactured separately using brazing and then assembled together using friction stir welding. This segmentation allows microchannels to be fabricated in manageable segments without requiring large brazing autoclaves, reducing manufacturing complexity while maintaining heat transfer efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from traditional brazing alone to a hybrid joining approach combining brazing with friction stir welding. This parameter change in the joining process enables modular assembly of microchannel ribs, overcoming the limitation of brazing autoclave size while preserving the thermal performance benefits of microchannels.

Inventive Principle:

Principle #35Parameter changes

2Strength

If brazing is used to secure fins in microchannel heat sinks, then structural integrity is improved, but microchannels become clogged resulting in low yields

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing yield

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The cooling ribs are fabricated as separate modular sections that are brazed independently, then joined to the frame using friction stir welding. This segmentation isolates the brazing process to smaller components, reducing the risk of microchannel clogging during brazing while maintaining structural integrity through the combination of brazing and friction stir welding.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Friction stir welding acts as an intermediary joining method between the brazed rib sections and the frame. This intermediary process provides an alternative joining path that does not involve brazing the entire assembly, thereby reducing the risk of microchannel clogging while still achieving secure attachment and maintaining structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If traditional cooling schemes are used for existing chassis, then system architecture changes are minimized, but cooling performance is insufficient for high-power electronic modules

Engineering Contradiction:

Improvesystem architecture compatibilityVSAvoidcooling performance

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The invention provides a flexible, modular cooling rib system that can be adapted to existing chassis architectures. The ribs can be configured in various patterns and sizes to fit different chassis geometries, allowing high-performance cooling to be integrated into existing systems without requiring complete architectural redesign, while still achieving the necessary cooling performance for high-power modules.

Inventive Principle:

Principle #15Dynamics

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 approach provides enhanced cooling capabilities for large-scale electronic assemblies by maintaining a constant rib temperature, increasing power density without raising the cold plate temperature, and reducing manufacturing costs through modular design and supplier accessibility.

Implementation Method 1

The invention, in one aspect, features the use of cooling ribs with microchannels therein in combination with a phase change coolant to provide an increased heat transfer coefficient and also isothermal cooling.

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

welding, (e.g., friction stir welding) techniques are used to secure the ribs to a frame member constructed to supply the phase change coolant to the individual cooling ribs

Methodology Applied

Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentUS9526192B2Cold chassis for electronic modules and method of making same

Publication Date: 2016.12.20 RAYTHEON CO

AI summary

A cold chassis and method of making a cold chassis for electronic modules featuring the fabrication of individual brazed cooling ribs each including microchannels along the length thereof and a peripheral flange. A set of adjacent ribs are secured together and assembled onto at least one face of a frame member. The rib flanges are sealed (e.g., friction stir welded) with respect to the frame member.