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Using FLUENT inDesign &

OptimizationDevendra Ghate, Amitay Isaacs,

!"dha#ar, A G $arathe, % $ $""mdar

Centre for Aerospace Systems Design and Engineering

Department of Aerospace Engineering, IIT Bombay

http://www.casde.iitb.ac.in/

http://www.casde.iitb.ac.in/http://www.casde.iitb.ac.in/http://www.casde.iitb.ac.in/http://www.casde.iitb.ac.in/http://www.casde.iitb.ac.in/http://www.casde.iitb.ac.in/

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FLUENT CFD Conference 2003 2

O"t'ine

(FD in design

%ro)'em statement

D"ct parametrization

F'o* so'"tion

+es"'ts

(onc'"sion

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FLUENT CFD Conference 2003 3

Using (FD in Design

!im"'ation Time (FD is ta#es h"ge amo"nts o time or rea' 'ie pro)'ems Design re-"ires repetitive r"ns o discip'inary ana'yses

Integration .ith optimizer .ith other discip'inary ana'yses /e0g0 grid generator1

A"tomation No "ser interaction sho"'d )e re-"ired or sim"'ation

Gradient Inormation No commercia' (FD so'vers provide gradient inormation (omp"tationa''y e2pensive and pro)'ematic / 1

to get gradient inormation or (FD so'vers /3nitedi4erence, a"tomatic di4erentiation1

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FLUENT CFD Conference 2003 4

$ethodo'ogy

Problem Specification

Parametrization

New parameters

eometr! eneration

ri" eneration

CFD problem set#p

Flow Sol#tion

$ptimization #sin%

S#rro%ate &o"els

'(S&) D*CE+

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FLUENT CFD Conference 2003 ,

$ethodo'ogy

Problem Specification

Parametrization

New parameters

eometr! eneration

ri" eneration

CFD problem set#p

Flow Sol#tion

$ptimization #sin%

S#rro%ate &o"els

'(S&) D*CE+

FLUENT

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FLUENT CFD Conference 2003 -

56D D"ct Design %ro)'em

Entry E2it

Location and shape #no*n

Geometry o d"ct rom Entry to E2it 7

%ress"re +ecovery8 Distortion8 !*ir'

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FLUENT CFD Conference 2003 .

%arametrization

Y

X

Z

XDuct

Centerline

A

X

(ontro' 9 Design

:aria)'es

8 ;m,

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FLUENT CFD Conference 2003 /

%arametrization/contd01

Y

X

Z

XDuct

Centerline

A

X

(ontro' 9 Design

:aria)'es

8 ;m,

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FLUENT CFD Conference 2003

Typica' 5D6D"cts

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FLUENT CFD Conference 2003 10

Grid Generation

eneration of entr! an" eit

sections #sin% *&T

Cl#sterin% Parameters

Con5ersion of file format to

CNS #sin% FLUENT

&es6 file

eneration of str#ct#re" 5ol#me

%ri" #sin% parametrizationri" parameters

Entr! 7 Eit sections

Con5ersion of str#ct#re" %ri"

to #nstr#ct#re" format

Complete %ri" %eneration process is

a#tomate" an" "oes not re8#ire

6#man inter5ention

Complete control o5er

9 Distance of t6e first cell from t6e wall

9 Cl#sterin%

9 N#mber of %ri" points

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FLUENT CFD Conference 2003 11

T"r)"'ence $ode'ing+e'evance> Time per !o'"tion

Fo''o*ing aspects o the ?o* *ere o interest> @o"ndary 'ayer deve'opment F'o* !eparation /i any1 T"r)"'ence Deve'opment

Literat"re !"rvey Doy'e night, !mith, ar'o4, Loe4er

(irc"'ar cross6section

!6shaped d"ct

@a'd*in6Loma2 mode' /A'ge)raic mode'1 (omp"tationa''y ine2pensive than more sophisticated mode's

no*n to give non6acc"rate res"'ts or )o"ndary 'ayer separation etc0

#6rea'iza)'e t"r)"'ence mode' T*o e-"ation mode' !t"dy )y Deva#i +avi "mar & !"ata @andyopadhyay /FLUENT

Inc01

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FLUENT CFD Conference 2003 12

T"r)"'ence $ode'ing /contd01

!tandard #6mode' T"r)"'ence :iscosity +atio

e2ceeding B,CC,CCC in =95ce''s

+ea'iza)'e #6mode' !hih et0 a'0 /B1 ( is not ass"med to )e

constant

A orm"'ation s"ggestedor ca'c"'ating va'"es o(B & (

(omp"tationa''y 'itt'emore e2pensive than thestandard #6mode'

Total Press#re profile at t6e

eit section 'Stan"ar" :; mo"el+

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FLUENT CFD Conference 2003 13

Distortion Ana'ysisD(CH /%AC %Cmin1 9-

*here,

%AC 6 average tota' press"re at the section,

%Cmin

6 minim"m tota' press"re in a CCsector, - 6 dynamic press"re at the crosssection0

User De3ned F"nctions /UDF1 and scheme 3'es*ere "sed to generate this inormation rom the

FLUENT case and data 3'e0Iterations may )e stopped *hen the distortionva'"es sta)i'ize at the e2it section *ithreasona)'e convergence 'eve's0

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FLUENT CFD Conference 2003 14

%ara''e' E2ec"tion

%ara''e' mode o operation in FLUENT

B6noded Lin"2 c'"ster

%orta)'e @atch !ystems orsched"'ing

@atch mode operation o FLUENT /6

g1!ca'e "p depends on grid size

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FLUENT CFD Conference 2003 1,

+es"'ts> Tota' %ress"re

%ro3'e

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FLUENT CFD Conference 2003 1-

+es"'ts /contd01

$ass im)a'ance> C0BJKEnergy im)a'ance>C0CK

Tota' press"re drop> B0=K:ario"s t"r)"'ence re'ated -"antities o interest at entryand e2it sections>

Entry E2it

T"r)"'ent ineticEnergy

B=0= 0

T"r)"'ent :iscosity

+atio =CB0 5=MM0

!

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FLUENT CFD Conference 2003 1.

!'apping

These are huge benefits as compared to the efforts involved.

$ethodo'ogy !tore the so'"tion in case & data 3'es

Open the ne* case /ne* grid1 *ith the o'd data 3'e

!et"p the pro)'em

!o'"tion o /C0B C05B B B1 d"ct s'apped on /C0B C05B C0B C0B1

3;"eca"e;fall -;"eca"e;fall

.itho"t s'apping =

.ith s'apping B5 MM%ercentage timesaving

JCK 5CK

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FLUENT CFD Conference 2003 1/

(onc'"sion

Time for sim#lation 6as been

re"#ce" to aro#n" 20? #sin%

parallel comp#tation an"

slappin%>

0 20 40 -0 /0 100

Time (hrs)

Time per CFD Run

Serial Run

Parallel Run

Slapping

Process of %eometr! 7 %ri" %eneration 6as been a#tomate" re8#irin%

no interacti5e #ser inp#t FLUENT 6as been c#stomize" for eas! inte%ration into an optimization

c!cle

CFD anal!sis mo"#le rea"! for incl#sion in optimization for a real life

problem

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FLUENT CFD Conference 2003 1

F"t"re .or#

F"rther e2p'oration andimprovement o s'apping

methodo'ogyIdenti3cation and assessment ooptim"m optimization a'gorithm

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Than# ;o"

http>99***0casde0iit)0ac0in9mdo95d6d"ct9

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FLUENT CFD Conference 2003 21

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FLUENT CFD Conference 2003 22

%ro)'em !tatement

9* "iff#sin% S;s6ape" "#ct9*mbient con"itions@ 11Am altit#"e9nlet o#n"ar! Con"itions

9Total Press#re@ 34,00 Pa9Total Temperat#re@ 2-1>4o A9B!"ra#lic Diameter@ 0>34m9T#rb#lence ntensit!@ ,?

9$#tlet o#n"ar! Con"itions9Static Press#re@ 310,1 Pa 'Calc#late" for t6e "esire" mass flow rate+9B!"ra#lic Diameter@ 0>4.02m9T#rb#lence ntensit!@ ,?

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FLUENT CFD Conference 2003 23

D"ct %arameterizationGeometry o the d"ct is derivedrom the $ean F'o* Line /$FL1 $FL is the 'ine oining centroids o

cross6sections a'ong the d"ct Any cross6section a'ong 'ength o the

d"ct is norma' to $FL

(ross6section area is varied

parametrica''y(ross6section shape in mergingarea is same as the e2it section

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FLUENT CFD Conference 2003 24

$FL Design :aria)'es 6 B

$ean ?o* 'ine /$FL1 is considered asa piece*ise c")ic c"rve a'ong the'ength o the d"ct )et*een the entry

section and merging section

y!", #!"

$ %m%m/&

y!%m/&", #!%m/&" specified

Centry

Cmerger

y', #'

y&, #&

%m : (distance between the entry and merger section

y', y&, #', #& : c)bic po*ynomia*s for y!" and #!"

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FLUENT CFD Conference 2003 2,

$FL Design :aria)'es 6 =+ y'!" A$- A' - A&

&- A, y&!" B$- B' - B&

&- B

+ #'!" C$- C' - C&&- C

, #&!" D$- D' - D&&- D

+ y'!%m" y& !%m", y'!%m" y&!%m", y'0!%m" y&0!%m"

+ #'!%m" #& !%m", #'!%m" #&!%m", #'0!%m" #&0!%m"

+ y'!Centry" y&!Cmerger" #' !Centry" #&!Cmerger" $

+ The shape of the 12% is contro**ed by & parameters whichcontro* the y and # coordinate of centroid at %m/&

+ y!%m/&" y!$" - !y!%" 3 y!$"" 4y $ 5 4y5 '

+ #!%m/&" #!$" - !#!%" 3 #!$"" 4

#$ 5 4

#5 '

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FLUENT CFD Conference 2003 2-

Area Design :aria)'es B

(ross6section area at any station is interpo'atedrom the entry and e2it cross6sections

+A!" A!$" - !A!%m"3A!$"" 6 7!"

+corresponding points on entry and

eit sections are *inear*y interpo*ated

to obtain the shape of the intermediatesections and sca*ed appropriate*y

+8section 8entry -!8eit( 8entry" 6 7

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FLUENT CFD Conference 2003 2.

Area Design :aria)'es 6 =

A$- A' - A&&- A

$ 7 5 7'

B$- B' - B&&- B

7'7 7&

C$- C' - C&&- C

7&5 7 '

7

7!"

$ %m

%m

/

$

'

&%m

/

7'

7&

7!%m/" and 7!&%m/" is specified

7 9ariation is gi9en by piecewise c)bic c)r9e as f)nction of