aluminium heat exchangers

7/31/2019 Aluminium Heat Exchangers

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Mechanical modelling for enhanced durability

Our modelling team can create a header plate and t ube model of your product which will allow you to identif y regions of high stressfor diff erent types of deformation. For example, the model can illustrate the effect of deformation due to pressurisation and thermaltube expansion. It can then be used to explore how gauge, fin location, braze dimensions, etc. affect regions of st ress. By using ourmechanical models in your product design, in-service failures can be avoided.

The modelling group is supported within Innoval by metallurgists and surface scientists who are t hemselves experts in the productionand processing of aluminium. For heat exchanger mater ials, there really is nowhere better than Innoval Technology for your modelling

requirements!

Innoval Technology Your Technical Partner for HeatExchanger Development

Residual carbon measurement how clean is your aluminium surface?

Brazing sheet suppliers the cleanliness of the aluminium surface you supply to your customerscan impact on t heir first time t hrough rates. Therefore, ensuring your residual carbon levels arethe lowest in the business could lead to significant competitive advantage.

At Innoval we can help you achieve this by firstly monitoring your residual carbon levels,and then using our thermal modelling techniques to opt imise your annealing process to

ensure all traces of lubricant are removed from the st rip before in-situoxidation occurs.

Header Plate Header Plate M odel C ontours show ing stresses upon

1mm tube displacement (1/ 4 model)

We are committed to providing world class expertise in aluminium alloys and brazing technology. Ourexperts have unique knowledge in materials characterisation and performance, coupled with extensiveproduct and process experience.

Innoval Technology is an independent company active in all stages of the Heat Exchanger supplychain. We have a unique view of the industry, and we can supply information on market t rends,new materials and processes, and new techniques to keepyou up to date with the latest developments.

Together w e can ensure you stay at the forefront

of your industr y.


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Thermal modelling for effective down-gauging

Our thermal modelling expertise will enable you to make your products smaller and lighter without reducing their perf ormance. We willuse our sophisticated thermal models to explore the relationship between key dimensions of your product and heat t ransfer performance.Specifically we will focus on:

Fin gauge and conductivity

Fin heightFillet width

Furthermore, we will explore each of t he above with dif ferent f in chemistries t o obtain a perf ect balance between mechanical properties,thermal conductivity and corrosion resistance.

We are confident t hat our modelling tools, coupled with our extensive product and process knowledge, will reduce the development timeand cost of your new products.

Is your system galvanically compatible?

Mo delling the braze fillet

Heat flow assumed

Fp

Fin

Fillet

TubeW

fill

t0

Mo del results: effect of fin thickness

As tube st ock continues to be down-gauged, it is becoming increasingly important to ensure yourfinstock remains sacrificial t o your t ube alloy, t hereby maximising the durability of your heatexchanger. Furthermore, your finstock must remain sacrificial irrespect ive of supplier. Thisis an important point to consider because it is the process route at your supplier whichinfluences galvanic compat ibilit y. Two alloys with the same composition can behave verydifferently when in a heat exchanger system.

We can ensure you have the best combination of finstock, tube-stock and header plate.We use a ZRA (zero resistance ammeter) to measure the galvanic compatibility of your

whole system in accordance with ASTM G71. We will t est all suppliers of each componentto ensure that there isnt one combination which could let you down.

Total galvanic charge of fin alloys against extruded tube

for 6 hours coupling in SW AAT solution

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-0.8

-0.3

0.2

0.7

1.2

GalvanicCurrent

Fin sacrificial

Tube sacrificial

Fin Alloy 1 Fin Alloy 2 Fin Alloy 3 Fin Alloy 4 Fin Alloy 5 Fin Alloy 6

Schematic of a the ZRA co nfiguration

Fin Alloy(WE II)

Tube Alloy(WE I)

Referenceelectrode

CE(Pt)

Air

5 wt% NaClsolution

Potentiostat


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Silicon part icle size analysis

The shape and distribution of the silicon particlesin your cladding affect its fluidity once molten.

Generally, large silicon part icles and those witha plate-like morphology inhibit the movement

of liquid into the joint. The silicon part icles cantherefore have a significant effect on brazeability.There are oft en variations in silicon compositionwithin the brazing sheet itself, as well as betweensuppliers.

At Innoval we can analyse the silicon part icles insamples from each of your suppliers so you canbe confident you are selecting the best materialfor your products. We use optical metallography,together with image analysis, to give you criticalinformation such as Feret ratio, size distribution

and equivalent circle diameter of the siliconparticles.

The Data-Map (D-MapTM) the tool for eff icient data capture and dissemination

When you embark on a mat erial characterisation programme either in-house or wit h Innoval Technology, a large quantit y of datais generated which gives you invaluable information about your products. However, this information is almost useless unless it isaccessible at all times to all parts of your business, irrespective of location. To help you manage this data, and to allow effectivedissemination, we have developed the Data-Map, or D-MapTM.

The D-M apTM is a software tool consist ing of a matrix with the axes defined as product tests vs products. Behind each intersection in

the matr ix there is a table of results for each test, together with any relevant charts or photographs. It is also possible to display theresults graphically.

The D-M apTM is designed to be held on your intranet so the results can be viewed by anyone with appropriate access. As morecharacterisation programmes are completed, your D-MapTM provides a user-friendly results archive to t rack changes in your materialsover time. Furthermore, it is very easy to add new products or new tests to the D-MapTM as your product portfolio increases.

Good s il icon part ic le s ize and dist r ibution Poor si licon part ic le s ize dist r ibut ion

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2.00

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0.00 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00

F min / F max

%o

fparticles

0.1 = Long and thin. 1.0 = Circle.

Supplier ASupplier BSupplier C

Feret ratios of Si particles (longitudinal)

Level 1 map Level 2 results table Level 3 result chart


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Innoval TechnologyBeaumont CloseBanburyOxonUK OX 16 1TQ

Tel: + 44 (0) 1295 702800Fax: + 44 (0) 1295 702898/ 9Email: [email protected]:/ / www.innovaltec.com

For more information contact:

Innovals range of servicesMaterials science

Process DevelopmentSimulation & Software DevelopmentKnowledge ManagementMaterials Characterisation & AnalysisTraining

Who are Innoval?Innoval Technology is an independentmaterials technology providerspecialising in aluminium and otherlight metals. We provide technicalexpertise, contract research,analytical and testing services.

The Innoval team has extensive industryexperience. We are equipped with themulti-disciplinary skills, knowledge andlatest technology to solve your materialsproblems and process development needs.

CapabilitiesMetallographic laboratory, sample preparationetching and anodising techniquesDigital image capture for microstructure andgrain structure characterisationMicro-hardness measurement

SEM/ EDX - imaging, analysis and elementmappingMicroprobe imaging, analysis and elementmappingTransmission electron microscope (external)Microtome sample preparation (TEM)FTIR (ATR, FT80, drifts, microscope andtransmission modes)Surface propert ies microbalance andgoniometerThermal analysis (TMA/ DSC)Heat treatment furnaces (up to 10000C)Gas chromatography

Paint and lacquer testing adhesion, hardnessand degree of cure, etc.Electrochemical and salt spay corrosion testingMechanical testing static and fat igue

A recent selection of our papersThe Development of Corrosion Resistant Extrusion Alloys for Heat Exchanger ApplicationsAFC Holcroft 9th Brazing Seminar October 2004

Magnesium Diffusion and Flux Interactions During Controlled Atmosphere Brazing (with Solvay Fluor)AFC Holcroft 9th Brazing Seminar October 2004

Low Temperature Brazing for Aluminium Heat Exchangers - Fact or Fiction?AFC Holcroft 10th Brazing Seminar October 2005

The Growth of Aluminium in Automotive Heat ExchangersAluminium, vol. 81, March 2005

The influence of silicon part icle morphology on the melt ing mechanism of aluminium brazing sheet (with Dana, Oakville)VTMS 7, M ay 2005, Toronto

aluminium heat exchangers

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