Project 2: Heat Exchanger Design

Group Members:Brian Schludecker

Phillip PalmerAdam Spindler

Mike HayJoe McGuire

Presented 12/12/2006 to Dr. Toksoy and ME 414 Class, IUPUI

Project Summary

• Design and optimization of heat exchanger• Specifications & objectives• Methods• Results• Conclusions

Heat Exchanger Specifications

• Heat exchanger length must not exceed 7 m• Shell diameter must not exceed 2 m• Shell mass flow rate: 120,000 kg/hr• Water in shell must cool from 40 C to 25 C• Water in tube enters at 20 C• Ignore fouling

Objectives

• Maximize Q• Minimize Weight (cost)• Minimize heat exchanger pressure drop

Design Strategy

• Configure MATLAB files to analyze the heat exchanger

• Modify input factors until heat transfer ratio is close to 1

• Run DOE in MATLAB and Minitab to calculate optimal values for system

Design Factors

• Tube outer diameter• Shell inner diameter• Tube length• Number of tube passes• Material• Pitch• Number of Baffles• Baffle Spacing

Design Factors for DOE

• Tube outer diameter• Shell inner diameter• Tube length• Number of tube passes• Material• Pitch• Number of Baffles• Baffle Spacing

Design Decisions

• Pitch = 1.25 * Tube outer diameter• 0 baffles

Interaction & Main Effects Plots(to find Critical Factors)

Interaction & Main Effects Plots(to find Critical Factors)

Mean Effects PlotsM

ean

of w

eigh

t

0.012700.00635

1500

1250

1000

750

5000.43820.3874 52

21

1500

1250

1000

750

500213

tube_od shell_id tube_len

tube_pass tub_mat

Main Effects Plot (data means) for weight

Mea

n of

q

0.012700.00635

3000000

2500000

2000000

1500000

10000000.43820.3874 52

21

3000000

2500000

2000000

1500000

1000000213

tube_od shell_id tube_len

tube_pass tub_mat

Main Effects Plot (data means) for q

Mea

n of

dp

shel

l

0.012700.00635

2500

2000

1500

10000.43820.3874 52

21

2500

2000

1500

1000213

tube_od shell_id tube_len

tube_pass tub_mat

Main Effects Plot (data means) for dp shell

Mea

n of

dp

tube

0.012700.00635

800000

600000

400000

200000

00.43820.3874 52

21

800000

600000

400000

200000

0213

tube_od shell_id tube_len

tube_pass tub_mat

Main Effects Plot (data means) for dp tube

Pareto ChartsTe

rm

Effect

ABEABCDEBCEBCDEABDEBEBDEABCDBCDABDABCACDEBDBCCDEABADEACEBDEACDCEAECDADEACD

CA

2000000150000010000005000000

138331Factor

tube_passE tub_mat

NameA tube_odB shell_idC tube_lenD

Pareto Chart of the Effects(response is q, Alpha = .10, only 30 largest effects shown)

Lenth's PSE = 76571.9

Term

Effect

ABCDABDEABDBCDEBCDACDEBDEACDBDADECDEADCDABCEDEABCDABEABBCEACEBEBCACAEBCEA

EC

10008006004002000

8Factor

tube_passE tub_mat

NameA tube_odB shell_idC tube_lenD

Pareto Chart of the Effects(response is weight, Alpha = .10, only 30 largest effects shown)

Lenth's PSE = 4.38469

Term

Effect

ABEABDEBEBCECDEBCDEBDECEABCDEABCEDEACDEAEACEADEABCDBCDABCBCABDBDABBACDCDACC

ADDA

8000007000006000005000004000003000002000001000000

0Factor

tube_passE tub_mat

NameA tube_odB shell_idC tube_lenD

Pareto Chart of the Effects(response is dp tube, Alpha = .10, only 30 largest effects shown)

Lenth's PSE = 1.345648E-10

Term

Effect

DEABCDECEACABCBCDEBCEBDEECBCBEABECDABCDABCECDEACEACDBCDACDEAEADEABDBDADD

ABBA

16001400120010008006004002000

0Factor

tube_passE tub_mat

NameA tube_odB shell_idC tube_lenD

Pareto Chart of the Effects(response is dp shell, Alpha = .10, only 30 largest effects shown)

Lenth's PSE = 1.179762E-13

Design Decisions

• Critical factors: Length, Shell ID, Tube OD• Material: Aluminum (cost, weight)• 1 pass

Optimized Results

Hi

Lo0.62872D

Optimal

Cur

d = 0.48564

Maximumq

d = 0.68952

Minimumdp tube

d = 0.67117

Minimumdp shell

d = 0.69525

Minimumweight

y = 1.971E+06

y = 3862.8936

y = 828.8276

y = 713.3242

2.0

5.0

0.3874

0.4890

0.0064

0.0159shell_id tube_lentube_od

[0.0138] [0.4890] [3.1253]Hi

Lo0.67904D

New

Cur

d = 0.61200

Targ: 2000000.0q

d = 0.88078

Minimumdp tube

d = 0.41952

Minimumdp shell

d = 0.94020

Targ: 1100.0weight

y = 1.806E+06

y = 1357.6620

y = 416.0955

y = 1076.0802

2.50

3.750

0.3912

0.5868

0.0110

0.0166shell_id tube_lentube_od

[0.0148] [0.5861] [3.3682]

+/- 20%

Using guesses (from Matlab):

Optimized results are not standardSize ID and OD, choose close sizes:

Optimized Specifications

• Tube OD = 0.0127 mm• Shell ID = 0.5906 m• Length = 3.3682 m

Final Results

• Q maximized 2.099E6 W

• dP in shell minimized 463 Pa• dP in tube minimized 1500 Pa• Weight minimized 1108 kg

Conclusions

• Minitab optimized values for ID and OD are not standard tube/shell sizes, need to adjust Minitab results

• Objectives achieved• Further analysis possible for multiple

passes/baffles• Questions?