Heat Pipes for Space Applications - Hexag Pipes for Space Applications Presented By: ... • NCG, proof pressure, helium leak test, ... Light Weight AGHP’s Scope unchanged

© Thermacore Europe Ltd. All Rights Reserved.

Thermacore Proprietary and Confidential.

Heat Pipes for Space Applications

Presented By: Dr Xiao YangDate: 20th May 2014

Contents:

• Brief General Introduction

• Space Technology Overview

• k-Core: Encapsulated Annealed Pyrolytic Graphite

• UK R&D: Light Weight & Structural CCHP

• UK R&D: Gravity Friendly Heat Pipes



Thermacore Business Units

3

Ashington, NorthumberlandUnited Kingdom

Lancaster, Pennsylvania (Headquarters)

k Technology DivisionLanghorne, PA – HQ & MFG

PMT DivisionPittsburgh, PA Engineering & Mfg.



K-Core Assemblies

Core Thermal Technologies

Heat Pipe Assemblies

Liquid Cold Plates

UK Vacuum Brazing Capability

PV/T Furnace with 1219mm x 1016 x 2540mm Hot Zone 650oC & 10-5 Vacuum or Inert Gas

WonderWare software to support NADCAP and AWS certification.

Brazing Liquid Cooling

Advantages

CleanLarge, complex, sizes possible



Space Technology Overview

• The following two slides present an example of how Thermacore’s products from all four divisions can be incorporated into a space application.

• Several technologies are currently only designed and manufactured in the USA and may be restricted by ITAR.

Axially Grooved Aluminum Heat Pipes

Copper Water Heat Pipes and k-Core® Thermal

Doublers

Thermal Straps

Satellite Thermal Control - Electronic Payload Elements

Satellite Thermal Control Payload Products

k-Core® DoublerThermal StrapsCopper-Water

Heat Pipes

Honeycomb Panel

k-Core®

2 4 531

8

CCHP’s

7

Electronics

Chassis

Loop Heat Pipes4

6

7

3

12

8

External Thermal Bus Structure

Elements

6 7

8

5

7



k-Core: Encapsulated Annealed Pyrolytic Graphite

Encapsulation Materials: Aluminium, Copper, Kapton, Carbon Fibre +++



Conduction cooled module, F35 standard

Standard APG configuration with core personalization

Up to 250 W heat dissipation through core

Aluminum encapsulation

Permits the use of COTS parts

6061-T4 aluminium encapsulated APG composite (k-Core)

Aluminum BaselineMax Surface Temperature – 59.8°C

Max Surface Temperature – 17.5°C

k-Core® Material

k-Core F35 Jet Aircraft Card Guide

Flexible and Formable Thermal Straps

Kapton-APG Thermal StrapDensity < 2 g/cm3

Thermal conductivity up to 1000 W/mKHigh dielectric breakdown strength

Copper Foil-APG Thermal Strap

Thermal Strap with metal end terminations to improve heat input & rejection. Eases attachment to the assembly

Launched November 2009NASA Express Logistics Carrier (ELC)

Equipment Deck

Launched November 2011k-Core Formed Thermal Conductor



Light Weight & Structural Axially Grooved Heat Pipes (AGHP)

TSB Space for Growth Flagship Program:

Telecom Satellite Mechanical Platform

http://images1.wikia.nocookie.net/__cb20100918130631/logopedia/images/b/bc/Astrium_logo_2010.png




CCHP Aim & Specification

Airbus Defence & Space

Telecom Satellite Platform

Orientation: 0° to +90°Heat Flux: 10 W/cm2

Heat Transport 100 to 200 W.mDifferent Groove Geometries availableContainer Material: AluminiumWorking Fluid = AmmoniaTemperature Range = -50 °C to +80 °C Length: 1 m to 5 m is typical

Aim to match performance of current CCHP’s:

Structural & Light Weight CCHP

Facilities• 2 x Ammonia charging rigs, 3rd rig under construction• NCG, proof pressure, helium leak test, thermal test



WP4100 Structural & Light Weight AGHP - Scope:Scope unchanged:• Very high-strength alloy (> 400 MPa)• Exceptional high-fatigue properties• Similar thermal properties to Al-6061• Replace structural elements • Potentially eliminate mass of AGHP

Structural Alloy AGHP’s

Light Weight AGHP’s Scope unchanged • 30% Lower mass than AL-6063• Comparable thermal performance to

current aluminium AGHP’s.• Large potential mass reduction• Thermal conductivity = 120 W/mK



Light Weight Materials Compatibility with Ammonia

• Light weight metal Prototypes passed NCG Test 1 in Reflux Mode (Vertical Orientation, -40°C)• Pipes progressed to Ageing (burn-in)• Specification requires 30 days at 105 °C with only trace NCG generation

- Rapid NCG generation caused heat pipe to fail.• Currently 3 x candidate light weight alloys are under investigation• Material composition analysis is being carried out to help identify reactive elements• Residual Gas Analyser to be procured to analyse NCG.

Burn-In Set-Up – Insulation Removed(without Refrigeration Flow)

NCG Test Set-Up

Refrigeration Supply lines Thermosyphon in Reflux Mode

Burn-In Thermocouple Positions

Technology Transfer Activities:• 2011-12: Charging Rig Upgrade and development of NCG test equipment & thermal

testing:

Thermal Test / NCG Rig

Ageing & Survival Temperature Test Rig

• Extrusion profile cleaning processes / equipment brought in-house

• Hardness test subcontractor developed

Upgraded Charging Rig

ESA comments noted regarding vertical (Reflow) ageing test



ARTES 5.1: 370-400 K Gravity-Friendly Heat Pipe with Low Freezing Temperature



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ARTES 5.1: 370-400 K Gravity-Friendly Heat Pipe with Low Freezing Temperature

• Heat pipe to function up to 200mm against gravity• >7 W/cm2 heat flux over evaporator region• Functionality up to 400 K (127 °C)

Aluminium Screen Mesh:

• Aluminium–Ammonia• Functionality with

gravity up to 90°

Sintered Steel Heat Pipe:

• Technology Transfer from TCI• Aluminium–Ammonia• Functionality against gravity

+90° to -90°

New HP Working Fluids:

• Compatibility investigation Extended temperature range (-40 to +250°C)



Proposed Prototypes:

• Proposed compatibility test pipes: straight, round pipes x 200 mm long• Mesh pipes: 200 mm long x 6mm outside diameter• Sintered pipes, initially straight, however end pipe may be bent as shown

below.

• L-Shaped Heat pipe / SLM Heat Pipe assembly• 40mm wide evaporator and condenser• Total power target = 30 W / assembly• Design selected based on standard dimensions

of an electronics box (suggested by Astrium)



Aluminium Sintered-Style Heat Pipes (SSHP)

SLM Manufacture of Complex 3D Geometries

• ALM manufacturing technique enables very complex component design• Create next generation tailored, sintered style aluminium capillary structures



Entire HP including end caps, wall, wick and fill tube can be made in a single process

Schematic of HP production process by SLM



SLM porous bits are made using a lattice structure which can be

regular or random

SLM porous structures

SLM porous structures

development

SLM heat pipe samples

SLM heat pipe samples and fill tube

SLM Development Samples

Arterial wick heat pipe made by SLM (14mm OD diameter and 70mm length)

SLM heat pipe samples porous grooved wick SLM heat pipe samples porous grooved wick

SLM porous sample - regular SLM porous sample - regular SLM porous sample - random

Two sample heat pipes were charged with ACETONE.

SLM functional heat pipes -Acetone

Thermal testing showed the prototypes to function against gravity, however further pore diameter reduction is required

• Prototype heat pipes welded to fill tubes• Protoypes passed both helium leak test

(<1x10-8 mBar l/s) and proof pressure test at 70 bar.



Thermacore Europe Ltd.

Thank you

Documents

Heat Pipes for Space Applications - Hexag Pipes for Space Applications Presented By: ... • NCG, proof pressure, helium leak test, ... Light Weight AGHP’s Scope unchanged