9th international phoenics user conference moscow, september 2002 a presentation by dr. paddy phelps...

9th International 9th International PHOENICS User PHOENICS User

ConferenceConferenceMoscow, September 2002Moscow, September 2002

A presentation by A presentation by

Dr. Paddy PhelpsDr. Paddy Phelps

on behalf of on behalf of

Flowsolve and IAC LtdFlowsolve and IAC Ltd

September 2002

Predicting air flow and heat transfer Predicting air flow and heat transfer in an anechoic test chamber in an anechoic test chamber

for industrial chillersfor industrial chillers

Outline of PresentationOutline of Presentation

Industrial ContextIndustrial Context Objectives of StudyObjectives of Study Benefits of using CFDBenefits of using CFD Description of CFD ModelDescription of CFD Model Simulations performed to dateSimulations performed to date Presentation of ResultsPresentation of Results ConclusionsConclusions

Chiller Test Chamber Chiller Test Chamber Ventilation studyVentilation study


Industrial ContextIndustrial Context

IAC LtdIAC Ltd design and construct a range design and construct a range of bespoke anechoic test chambers.of bespoke anechoic test chambers.

Their client in this instance was Their client in this instance was York York LtdLtd, manufacturers of air chiller , manufacturers of air chiller units for building HVAC systems. units for building HVAC systems.

York wish to improve the design of York wish to improve the design of their products by testing them at the their products by testing them at the limits of their performance envelopelimits of their performance envelope

Industrial ContextIndustrial Context

Test chamber design brief calls for air Test chamber design brief calls for air supply temperatures at chiller intakes supply temperatures at chiller intakes to be to be uniform to within 1uniform to within 100CC . .

Chiller unit intakes are located along Chiller unit intakes are located along upper body sides and ends. upper body sides and ends.

Up to 12 ducted fans on top of unit Up to 12 ducted fans on top of unit emit highly swirling air extract flow, emit highly swirling air extract flow, several degrees different from ambient several degrees different from ambient

Test Chamber Geometry - Test Chamber Geometry - 1 1

IAC Ltd Chiller Test IAC Ltd Chiller Test Chamber ventilation studyChamber ventilation study


Objectives of StudyObjectives of Study

Use simulation tools to predict mixing of Use simulation tools to predict mixing of hot swirling extract flow with ambient hot swirling extract flow with ambient airflow inside test facility airflow inside test facility

Provide input to design of chamber air Provide input to design of chamber air supply / extract arrangements, by supply / extract arrangements, by predicting likely effect on airflow patternspredicting likely effect on airflow patterns

Confirm client criteria for uniformity of Confirm client criteria for uniformity of temperature at chiller intakes can be mettemperature at chiller intakes can be met

Simulation Tool OptionsSimulation Tool Options

Direct ExperimentDirect Experiment• not applicable - building not yet constructednot applicable - building not yet constructed• use to confirm other predictive toolsuse to confirm other predictive tools

Wind-Tunnel ModellingWind-Tunnel Modelling• scale-up and thermal representation difficultscale-up and thermal representation difficult• problem with interpretation of resultsproblem with interpretation of results

Numerical SimulationNumerical Simulation• passive (Gaussian) dispersion modelspassive (Gaussian) dispersion models• Computational Fluid DynamicsComputational Fluid Dynamics


Industrial ContextIndustrial Context Objectives of StudyObjectives of Study Benefits of using CFDBenefits of using CFD Description of CFD Model Description of CFD Model Simulations performed to dateSimulations performed to date Presentation of ResultsPresentation of Results ConclusionsConclusions

Benefits of CFD ApproachBenefits of CFD Approach

No scale-up problemNo scale-up problem Three-dimensional, steady or transientThree-dimensional, steady or transient Interrogatable predictionsInterrogatable predictions Handles effect of Handles effect of

• blockages in domainblockages in domain• recirculating flowrecirculating flow• multiple inlets and outletsmultiple inlets and outlets• multiple interacting heat sourcesmultiple interacting heat sources

Solution Domain(s)Solution Domain(s)

CHAMBER MODELCHAMBER MODEL Solution domain encompasses the test Solution domain encompasses the test

chamber up to, but not including, the chamber up to, but not including, the outlet plenumoutlet plenum• Domain 15.22m by 18.88m by 8m highDomain 15.22m by 18.88m by 8m high

PLENUM MODELPLENUM MODEL Solution domain encompasses the outlet Solution domain encompasses the outlet

plenum onlyplenum only• Domain 12.2m by 17.08m by 1.3m highDomain 12.2m by 17.08m by 1.3m high

CFD Model Description - CFD Model Description - 11

Representation of the effects ofRepresentation of the effects of• blockage due to the presence of an blockage due to the presence of an

internal obstacle (chiller unit)internal obstacle (chiller unit)• multiple inlets and outlets for chamber air multiple inlets and outlets for chamber air • resistance and mixing in extract resistance and mixing in extract

silencerssilencers• distributed intakes on chiller sides & endsdistributed intakes on chiller sides & ends• discrete, swirling outlets on chiller topdiscrete, swirling outlets on chiller top

[ Flow inside chiller not solved for ][ Flow inside chiller not solved for ]


Dependent variables solved for :Dependent variables solved for :• pressure (total mass conservation)pressure (total mass conservation)• axial, lateral and vertical velocity componentsaxial, lateral and vertical velocity components• air/chiller effluent mixture temperatureair/chiller effluent mixture temperature• air residence time in chamber air residence time in chamber • turbulence kinetic energyturbulence kinetic energy• turbulence energy dissipation rateturbulence energy dissipation rate

Independent Variables:Independent Variables:• 3 spatial co-ordinates (x,y,z) and time3 spatial co-ordinates (x,y,z) and time


Iterative “guess and correct” solution Iterative “guess and correct” solution procedure to convergence of schemeprocedure to convergence of scheme

Typical domain size - 15x8x19 m. Typical domain size - 15x8x19 m. Around 1500 “sweeps” of domain Around 1500 “sweeps” of domain

required for convergencerequired for convergence Typical nodalisation level - 207,000Typical nodalisation level - 207,000 Convergence involves solution of around Convergence involves solution of around

2,500 million simultaneous linked 2,500 million simultaneous linked differential equationsdifferential equations


The set of partial differential equations The set of partial differential equations is solved within the defined solution is solved within the defined solution domain and on a prescribed numerical domain and on a prescribed numerical gridgrid

The equations represent conservation The equations represent conservation of mass, energy and momentum of mass, energy and momentum

The momentum equations are the The momentum equations are the familiar Navier-Stokes Equations which familiar Navier-Stokes Equations which govern fluid flowgovern fluid flow


The equations may each be written in The equations may each be written in the formthe form

D( ) /Dt + div ( U - grad ) = S{

Terms cover transience, convection, Terms cover transience, convection, diffusion and sources respectivelydiffusion and sources respectively

Equation is cast into finite volume form Equation is cast into finite volume form by integrating it over the volume of by integrating it over the volume of each celleach cell

IAC Ltd Chiller Test IAC Ltd Chiller Test Chamber Ventilation StudyChamber Ventilation Study

Industrial ContextIndustrial Context Objectives of StudyObjectives of Study Benefits of using CFDBenefits of using CFD Description of CFD ModelDescription of CFD Model Simulations performed Simulations performed Results ObtainedResults Obtained ConclusionsConclusions

Supply / Extract Supply / Extract Arrangements StudiedArrangements Studied

Chamber air supply arrangementChamber air supply arrangement• Straight supply ductsStraight supply ducts• Angling of supply end regionsAngling of supply end regions• Blocking middle regionBlocking middle region

Chamber air extract arrangementChamber air extract arrangement• Long side outlet ductsLong side outlet ducts• Small additional centre outletSmall additional centre outlet• Large centre outletLarge centre outlet• Small vestigial side outletsSmall vestigial side outlets

Chamber Geometry Chamber Geometry Arrangements StudiedArrangements Studied

Effect on chiller intake temperatures of:Effect on chiller intake temperatures of:

• Friction on walls & ceilingFriction on walls & ceiling• Silencer pressure losses at inlet & Silencer pressure losses at inlet &

outlet outlet • Mid-height wall “lip” Mid-height wall “lip” • End “hood” on chillerEnd “hood” on chiller• Baffles along chiller sidesBaffles along chiller sides• ““Lip” around centre ceiling extractLip” around centre ceiling extract• ““Swirl breaker” above chillerSwirl breaker” above chiller

Chiller Operating Conditions Chiller Operating Conditions StudiedStudied

Chamber dimensionsChamber dimensions• Dimensions 2.2 x 8..7 x 2.44 m. highDimensions 2.2 x 8..7 x 2.44 m. high• 12 outlet fans, swirl angle = 30 degrees 12 outlet fans, swirl angle = 30 degrees

Chiller “Hot” Operating ConditionChiller “Hot” Operating Condition• Inlet temperature ~ 35 deg.C Inlet temperature ~ 35 deg.C • Heat input = 951kW or 1019 kWHeat input = 951kW or 1019 kW• Air flowrate = 75 or 67 mAir flowrate = 75 or 67 m33/s/s

Chiller “Cold” Operating ConditionChiller “Cold” Operating Condition• Inlet temperature ~ 7 deg.CInlet temperature ~ 7 deg.C• Heat input = -363kW Heat input = -363kW

Chamber Operating Chamber Operating Conditions StudiedConditions Studied

Chamber Air supply RateChamber Air supply Rate• Initially 110% of chiller throughput Initially 110% of chiller throughput

( i.e. 1.1*75 = 82.5 m( i.e. 1.1*75 = 82.5 m33/s]/s]• Subsequently increased to 90 mSubsequently increased to 90 m33/s/s

Hot Operating ConditionHot Operating Condition• Inlet supply temperature = 35 deg.C Inlet supply temperature = 35 deg.C

Cold Operating ConditionCold Operating Condition• Inlet supply temperature = 7 deg.CInlet supply temperature = 7 deg.C

Overview of WorkscopeOverview of Workscope

34 simulations performed in 7 “stages”34 simulations performed in 7 “stages”• Stage 1Stage 1 - Original design concept; effect of - Original design concept; effect of

swirl; add small central outlet; remove swirl; add small central outlet; remove lateral offset; longer central outlet; add wall lateral offset; longer central outlet; add wall friction; hot & cold runsfriction; hot & cold runs

• Stage 2Stage 2 - chamber outflow partitioning - chamber outflow partitioning sensitivity; effect of inclining and part-sensitivity; effect of inclining and part-blocking some of supply inlets blocking some of supply inlets

• Stage 3Stage 3 - revised chiller inflow partitioning; - revised chiller inflow partitioning; Central outlet lip and vestigial side outletsCentral outlet lip and vestigial side outlets

Overview of WorkscopeOverview of Workscope

34 simulations performed in 7 “stages”34 simulations performed in 7 “stages”• Stage 4Stage 4 - chiller swirl level; outlet silencer - chiller swirl level; outlet silencer

resistance; central outlet lip. resistance; central outlet lip. • Stage 5Stage 5 - Increase chamber air rate; chiller - Increase chamber air rate; chiller

end and side baffles; increase chiller heat end and side baffles; increase chiller heat rate and reduce throughput for “worst rate and reduce throughput for “worst case”.case”.

• Stage 6Stage 6 - Worst case run with “swirl - Worst case run with “swirl breaker”breaker”

• Stage 7Stage 7 - Air loading run with chiller off. - Air loading run with chiller off.

IAC Ltd Chiller Test IAC Ltd Chiller Test Chamber Ventilation StudyChamber Ventilation Study

Industrial ContextIndustrial Context Objectives of StudyObjectives of Study Benefits of using CFDBenefits of using CFD Description of CFD ModelDescription of CFD Model Simulations performed Simulations performed Results ObtainedResults Obtained ConclusionsConclusions

Original Design ConceptOriginal Design Concept

ConfigurationConfiguration• Two long low-resistance side outletsTwo long low-resistance side outlets• No central outlet No central outlet

SupplySupply• Chamber supply rate = 82.5 mChamber supply rate = 82.5 m33/s/s• Chamber supply temp = 35 deg. CChamber supply temp = 35 deg. C

““Hot” Chiller Operating ConditionHot” Chiller Operating Condition• Chiller throughtput = 75 mChiller throughtput = 75 m33/s/s• Temperature rise through chiller = 11.17 Temperature rise through chiller = 11.17

deg C deg C

Original Design Concept:Original Design Concept:Predictions - 1Predictions - 1

Max temperature difference across Max temperature difference across chiller intake ports = 7.99 chiller intake ports = 7.99 ooCC

Min intake temperature = 35.1 Min intake temperature = 35.1 ooCC Max intake temperature = 43.1 Max intake temperature = 43.1 ooC C Mean intake temperature = 36.65 Mean intake temperature = 36.65 ooCC

Mean intake residence time = 7.46 Mean intake residence time = 7.46

secsec Max chamber residence time = 72.1 secMax chamber residence time = 72.1 sec

Original Design Concept:Original Design Concept: Predictions - 2 Predictions - 2

Original Design Concept:Original Design Concept: Initial Findings Initial Findings

Hot, highly swirling flow from chiller Hot, highly swirling flow from chiller outlet creates non-symmetric flow outlet creates non-symmetric flow patterns in chamber, despite symmetry patterns in chamber, despite symmetry of inlet, outlet and chiller locationsof inlet, outlet and chiller locations

Hot recirculating flow re-entrained into Hot recirculating flow re-entrained into chiller end intakes, creating a “hot end” chiller end intakes, creating a “hot end” and a “cold” endand a “cold” end

Intake temperature differences are Intake temperature differences are eight times desired criterion …...eight times desired criterion …...

Stage 1 SimulationsStage 1 Simulations

Effect of chiller outlet swirl levelEffect of chiller outlet swirl level• reducing swirl improves matters …reducing swirl improves matters …

(but this is not an option)(but this is not an option) add small central outletadd small central outlet

T reduced to 4.35 T reduced to 4.35 ooCC lengthen central outletlengthen central outlet

T increases slightly to 4.85 T increases slightly to 4.85 ooCC

Stage 1 SimulationsStage 1 Simulations

Chamber wall frictionChamber wall frictionT reduced slightly to 4.52 T reduced slightly to 4.52 ooCC

Hot and Cold OperationHot and Cold OperationT for cold operation about half that when T for cold operation about half that when

hothot

Hot operating condition will thus be the Hot operating condition will thus be the worst case for achieving the chiller worst case for achieving the chiller intake temperature uniformity criterionintake temperature uniformity criterion

Stage 2 SimulationsStage 2 SimulationsSupply/Extract geometry Supply/Extract geometry

sensitivitysensitivity

Chamber outflow partitioning sensitivityChamber outflow partitioning sensitivity• Tinkering with outlet resistance does not Tinkering with outlet resistance does not

improve matters. improve matters. T in range 4.5 to 6T in range 4.5 to 6ooCC Inclining the outer supply inlets Inclining the outer supply inlets

• Directing outer inlet jets towards chiller Directing outer inlet jets towards chiller ends, to sweep away descending hot fluid ends, to sweep away descending hot fluid from intakes, does hot have desired effect.from intakes, does hot have desired effect.

T in range 4.5 to 5T in range 4.5 to 5ooCC

Stage 2 SimulationsStage 2 SimulationsSupply/Extract geometry Supply/Extract geometry

sensitivitysensitivity

Blocking the lower centre supply Blocking the lower centre supply inlets inlets • Blocking the central lower inlet Blocking the central lower inlet

increases the incoming momentum of increases the incoming momentum of supply jets towards chiller sides . supply jets towards chiller sides . Does hot have very dramatic effect, Does hot have very dramatic effect, reducing reducing T by about 0.1T by about 0.1ooCC

Stage 3 SimulationsStage 3 SimulationsSensitivity to Chiller Inflow Sensitivity to Chiller Inflow

specificationspecification

Chiller inflow partitioning (ends, Chiller inflow partitioning (ends, sides, base) derived from :sides, base) derived from :

Manufacturers EstimatesManufacturers Estimates• For hot operation, For hot operation, T is about 5.3T is about 5.3ooCC

IAC Experimental MeasurementsIAC Experimental Measurements• For comparable run, For comparable run, T is about 3.1T is about 3.1ooCC• these more reliable data used for these more reliable data used for

subsequent simulationssubsequent simulations

Stage 3 SimulationsStage 3 SimulationsExtract geometry sensitivity Extract geometry sensitivity

Central outlet lipCentral outlet lip • Adding a deep lip around periphery of Adding a deep lip around periphery of

central roof outlet central roof outlet shouldshould allow capture allow capture of more of swirling flow from chiller top. of more of swirling flow from chiller top.

• Unfortunately, it also provides a shortcut Unfortunately, it also provides a shortcut for hot air to the ends, leading to a for hot air to the ends, leading to a dramatic increase in dramatic increase in T !T !

Moral: Not all intuitive aids work as one Moral: Not all intuitive aids work as one might expect . . .might expect . . .

Unexpected Outcomes . . .Unexpected Outcomes . . .

Stage 3 SimulationsStage 3 SimulationsExtract geometry sensitivityExtract geometry sensitivity

Further enlarged central outlet Further enlarged central outlet with vestigial side extract ductswith vestigial side extract ducts• Long extract ducts on each side Long extract ducts on each side

replaced by four smaller apertures at replaced by four smaller apertures at intervals; central outlet further intervals; central outlet further enlarged, but no lip. enlarged, but no lip. T falls to about T falls to about 2.72.7ooCC

Stage 4 SimulationsStage 4 Simulations SensitivitySensitivity to chiller outlet swirl to chiller outlet swirl

levellevel

For a reference geometry & “hot” For a reference geometry & “hot” operationoperation

effect is dramatic . . . . .effect is dramatic . . . . .• for 0% swirl, for 0% swirl, T is about 0.6T is about 0.6ooCC• for 30% swirl, for 30% swirl, T is about 1.3T is about 1.3ooCC• for 100% swirl, for 100% swirl, T is about 6.0T is about 6.0ooC C

Stage 4 SimulationsStage 4 SimulationsFurther i/o geometry sensitivityFurther i/o geometry sensitivity

Outlet silencer resistanceOutlet silencer resistance• Specification of high and low resistance Specification of high and low resistance

zones in inner and outer regions of zones in inner and outer regions of central outlet has small (~10% reduction) central outlet has small (~10% reduction) effect on effect on T T

Increase airflow from 82.5 mIncrease airflow from 82.5 m33 to 90 m to 90 m33

• Increasing ventilation rate has a greater Increasing ventilation rate has a greater effect, reducing effect, reducing T by about 25%T by about 25%

Stage 5 SimulationsStage 5 SimulationsSensitivity to internal “baffles”Sensitivity to internal “baffles”

Side and end baffles added, to Side and end baffles added, to • channel supply air to intakes at chiller channel supply air to intakes at chiller

ends;ends;• prevent descending hot air plume being re-prevent descending hot air plume being re-

entrained into end inlets’entrained into end inlets’

Baffles and shrouds do not perform quite as Baffles and shrouds do not perform quite as envisaged . . . envisaged . . .

• Dead zones form in end shrouds, negating Dead zones form in end shrouds, negating some of supply-air channelling benefit .some of supply-air channelling benefit .

• However, However, T reduced by about two thirds T reduced by about two thirds

Baffled and ShroudedBaffled and Shrouded- - - - Tried and rejected - - Tried and rejected - -

Baffled and ShroudedBaffled and Shrouded- - - - Tried and rejected - -Tried and rejected - -

Final SimulationsFinal SimulationsWorst case Operating ScenarioWorst case Operating Scenario

Chamber air flow increased to 90 Chamber air flow increased to 90 mm33/s/s

Chiller air flow reduced to 67 mChiller air flow reduced to 67 m33/s/s

Chiller heat input increased to 1051 Chiller heat input increased to 1051 kWkW

Final Design ConceptFinal Design Concept

Geometry :Geometry :• No baffles or end hoodsNo baffles or end hoods• Normally-directed air supplyNormally-directed air supply• Side-wall ridge at mid-height Side-wall ridge at mid-height • Enlarged central extract with four small Enlarged central extract with four small

extracts along each sideextracts along each side• Shallow centre outlet “lip”Shallow centre outlet “lip”• ““Swirl Breaker” fitted between chiller Swirl Breaker” fitted between chiller

top and air extract ducttop and air extract duct

Final Design Concept :Final Design Concept :[ wall & roof tiles removed for clarity][ wall & roof tiles removed for clarity]

Final Design Concept :Final Design Concept : [ wall & roof tiles removed for clarity][ wall & roof tiles removed for clarity]

Final Design Concept:Final Design Concept:Predictions - 1Predictions - 1

Max temperature difference across Max temperature difference across chiller intake ports = 0.96 chiller intake ports = 0.96 ooCC

Min intake temperature = 35.01 Min intake temperature = 35.01 ooCC Max intake temperature = 35.97 Max intake temperature = 35.97 ooC C Mean intake temperature = 35.13 Mean intake temperature = 35.13 ooCC

Mean intake residence time = 4.27 Mean intake residence time = 4.27

secsec Max chamber residence time = 128 secMax chamber residence time = 128 sec

Final Design Concept :Final Design Concept :Predictions - 2Predictions - 2

Final Design Concept :Final Design Concept :Air flow predictionsAir flow predictions - axial plane- axial plane

Final Design Concept :Final Design Concept :Air flow predictions - transverse planeAir flow predictions - transverse plane

Final Design Concept :Final Design Concept :Air flow predictions - plan viewAir flow predictions - plan view

Final Design Concept :Final Design Concept :Residence time ConsiderationsResidence time Considerations

Flow-averaged residence time of air Flow-averaged residence time of air in chamber is ~19 secs. Maximum in chamber is ~19 secs. Maximum predicted is 128 seconds.predicted is 128 seconds.

Region located below mid-wall lip, Region located below mid-wall lip, at non-control panel end and side, at non-control panel end and side, is the slowest clearing dead zone.is the slowest clearing dead zone.

Times contoured depict “time Times contoured depict “time following injection” into domainfollowing injection” into domain

Final Design Concept :Final Design Concept :Residence time predictionsResidence time predictions

Final Design Concept :Final Design Concept :Residence time predictions atResidence time predictions at

axial section through centre of chilleraxial section through centre of chiller

Final Design Concept :Final Design Concept :Residence time predictions at Residence time predictions at

transverse section through centre of transverse section through centre of

chillerchiller

Final Design Concept :Final Design Concept :Residence time predictions at Residence time predictions at

transverse section through far end of transverse section through far end of

chillerchiller

Conclusions - 1Conclusions - 1

Attainment of 1-degree or less Attainment of 1-degree or less variance in chiller intake variance in chiller intake temperatures is thwarted by the re-temperatures is thwarted by the re-entrainment of the hot swirling plume entrainment of the hot swirling plume issuing from the top.issuing from the top.

Attempts to modify air flow patterns Attempts to modify air flow patterns to rectify matters by tinkering with to rectify matters by tinkering with inlets, outlets, baffles etc. only met inlets, outlets, baffles etc. only met with partial successwith partial success


Breakthrough came in controlling the Breakthrough came in controlling the influence of the highly swirling chiller influence of the highly swirling chiller -outlet flow, by use of a “waffle-iron” -outlet flow, by use of a “waffle-iron” type of swirl-breaker device.type of swirl-breaker device.

This was more effective than using This was more effective than using measures to try to divert the flow measures to try to divert the flow further downstream.further downstream.


Final design concept can meet the Final design concept can meet the

client’s design criterion for client’s design criterion for

acceptable variance in chiller intake acceptable variance in chiller intake

temperatures.temperatures.

Some “fine-tuning” may be required Some “fine-tuning” may be required

upon final installationupon final installation

ClosureClosure

Final ConceptFinal ConceptInitial ConceptInitial Concept

P.S. . . . . . .P.S. . . . . . .

And so they went ahead and built And so they went ahead and built the test chamber . . . . .the test chamber . . . . .

The fanfare of trumpetsThe fanfare of trumpets

P.S. . . . . . .P.S. . . . . . .

But the bean counters saidBut the bean counters said

“ “ let’s try to do without the swirl breaker “let’s try to do without the swirl breaker “

and verily the measured results fell shortand verily the measured results fell short

of the client’s design specification .of the client’s design specification .

and so they put the swirl breaker back, and so they put the swirl breaker back,

and came back for more modelling , and came back for more modelling ,

to “ fine tune ” the designto “ fine tune ” the design

The Test Chamber The Test Chamber “ as built ”“ as built ”

Changes to model for Changes to model for “ as built “ test cell “ as built “ test cell

geometrygeometry

Smaller 10-fan unit, located symmetricallySmaller 10-fan unit, located symmetrically

and reversedand reversed Chiller intakes: uniform flux along sides Chiller intakes: uniform flux along sides

and bases of units, but not at endsand bases of units, but not at ends Anti-clockwise swirl at chiller fan outletsAnti-clockwise swirl at chiller fan outlets Prescribed, non-uniform fan outlet Prescribed, non-uniform fan outlet

temperatures; intake values computedtemperatures; intake values computed Non-uniform fan swirl profileNon-uniform fan swirl profile


geometrygeometry

Domain extended upwards to Domain extended upwards to include representation of outlet include representation of outlet plenumplenum

Non-uniform inlet flow distribution, Non-uniform inlet flow distribution, based on measured valuesbased on measured values

Triangular-section wall protrusionsTriangular-section wall protrusions “ “ Fine mesh ” swirl breakerFine mesh ” swirl breaker

Model for “ as built “ Model for “ as built “ test cell geometrytest cell geometry


geometrygeometry

Chamber air flow up to Chamber air flow up to 92.592.5 m m33/s/s

Chiller throughflow up to Chiller throughflow up to 7272mm33/s/s

Chiller heat input down to Chiller heat input down to 869869 kW kW

Grid nodalisation up to Grid nodalisation up to 276,000276,000

cellscells

“ “ As Built “ Test Cell As Built “ Test Cell Geometry :Geometry :

“ Fine tuning ” simulations“ Fine tuning ” simulations

Effect on intake temperature profile Effect on intake temperature profile

ofof

Uniform and non-uniform TUniform and non-uniform Tfanfan

distributionsdistributions

Swirl breaker fitmentSwirl breaker fitment

Fan swirl angleFan swirl angle


geometrygeometry

Run SpecificationRun Specification Non-uniform fan outlet Non-uniform fan outlet

temperatures, based on temperatures, based on experimental measurements. experimental measurements. Maximum temperature = 54.4Maximum temperature = 54.4ooCC

Minimum temperature = 42.6Minimum temperature = 42.6ooCC Fan swirl angle 45Fan swirl angle 45oo

“ “ As built ” swirl breaker designAs built ” swirl breaker design

“ “ As built ” test cell As built ” test cell geometry:geometry:Flow pattern at chiller Flow pattern at chiller intakesintakes

“ “ As built ” test cell As built ” test cell geometry:geometry:Temperatures at intake Temperatures at intake levellevel

“ “ As built ” test cell As built ” test cell geometry:geometry:Flow patterns at fan outlet Flow patterns at fan outlet levellevel

“ “ As built ” test cell As built ” test cell geometry:geometry:Temperatures at fan outlet Temperatures at fan outlet levellevel

“ “ As built ” test cell: Flow As built ” test cell: Flow patterns patterns below swirl-breaker levelbelow swirl-breaker level

“ “ As built ” cell: As built ” cell: Temperatures Temperatures

below swirl-breaker levelbelow swirl-breaker level

“ “ As built ” test cell: Flow As built ” test cell: Flow patterns patterns at central outlet lip levelat central outlet lip level

“ “ As built ” cell: As built ” cell: Temperatures Temperatures at central outlet lip levelat central outlet lip level

“ “ As built ” cell : Flow As built ” cell : Flow patterns at section patterns at section through fans 3 & 4through fans 3 & 4

“ “ As built ” cell : As built ” cell : Temperatures at section Temperatures at section through fans 3 & 4through fans 3 & 4

“ “ As built ” cell : Flow As built ” cell : Flow patterns at section patterns at section through fans 7 & 8through fans 7 & 8

“ “ As built ” cell : As built ” cell : Temperatures at section Temperatures at section through fans 7 & 8through fans 7 & 8

“ “ As built ” cell : Flow As built ” cell : Flow patterns at section patterns at section through near-side fans through near-side fans

“ “ As built ” cell : As built ” cell : Temperatures at section Temperatures at section through near-side fansthrough near-side fans

“ “ As built ” cell : Flow As built ” cell : Flow patterns at section patterns at section through far-side fansthrough far-side fans

“ “ As built ” cell : As built ” cell : Temperatures at section Temperatures at section through far-side fansthrough far-side fans

“ “ As built ” test cell : As built ” test cell : Chiller intake temperature Chiller intake temperature profileprofile

ConclusionsConclusions

Highly non-uniform fan discharge Highly non-uniform fan discharge temperatures lead to inlet temperature temperatures lead to inlet temperature variations along length of unitvariations along length of unit

Local fluctuations can exceed 1 degree, Local fluctuations can exceed 1 degree, especially close to top of unitespecially close to top of unit

However, mixed-mean values for each However, mixed-mean values for each unit remain well below this criterionunit remain well below this criterion

THANK YOU FOR YOUR THANK YOU FOR YOUR ATTENTIONATTENTION

Points of ContactPoints of Contactfor further informationfor further information

Flowsolve LtdFlowsolve Ltd

Dr. Paddy PhelpsDr. Paddy Phelps

Dr. David GlynnDr. David Glynn

130 Arthur Rd.130 Arthur Rd.

Wimbledon ParkWimbledon Park

SW19 8AASW19 8AA

0208 944 09400208 944 0940

[email protected]@flowsolve.com

IAC LtdIAC Ltd

Mr. Geoff HowseMr. Geoff Howse

Mr. Greg SmithMr. Greg Smith

IAC HouseIAC House

Moorside RoadMoorside Road

WinchesterWinchester

Hants SO23 7USHants SO23 7US

01962 87300001962 873000

9th international phoenics user conference moscow, september 2002 a presentation by dr. paddy phelps...

Documents

b convergence

b representation

b york

test facility b

b dependent variables

airflow patterns b

problem b threedimensional

b iterative guess