CUMMINS CONFIDENTIAL HE Design Optimization ME414 – Thermal Fluid System Design Professor John Toksoy Final Project Team Members: Kaela Hlaulani Prince Bedell William Broaddus Derek Vleck Trever Zike Seth Simonson
Jan 07, 2016
CUMMINS CONFIDENTIAL
HE Design Optimization
ME414 – Thermal Fluid System DesignProfessor John Toksoy
Final Project
Team Members:Kaela HlaulaniPrince Bedell
William BroaddusDerek VleckTrever Zike
Seth Simonson
CUMMINS CONFIDENTIAL
Project Definition
Design heat exchanger to reduce fluid by 20 degrees Celsius.
Mass flow rate at the inlet of tube side is fixed at 220,000 kg/hr.
Inlet flow rate of shell is a design parameter. Inlet temperature of shell fluid is 20 degrees
Celsius. Both fluids are considered as water.
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Design Optimization Goals
System must cool fluid from 45 C to 25 C Length of Heat Exchanger cannot
exceed 7 m Shell Diameter cannot exceed 2 m Shell and Tube weight must be
minimized Pressure drop of Shell and Tube must
also be minimized
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Introduction
MATLAB is used to perform DOE runs. Minitab is used to evaluate the importance of the
variables according to the DOE runs (Main Effect Plots).
Relatively unimportant variables are selected and eliminated (fixed).
Most important variables are optimized using Minitab.
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Design – Funneling Process
Single Factor Runs:
I_Counter Flow
Mdot shell
Tube Length
Baffle Space
Tube Thickness
# Tube Passes
Baffle Cut
Shell ID
Shell Thickness
Shell Material
Tube OD
11stst Step: Analyze all 11 variables Step: Analyze all 11 variables 22ndnd Step: Two Factor DOE’s Step: Two Factor DOE’s 33rdrd Step: Critical Variables Optimization Step: Critical Variables Optimization
2 Factor DOE Runs:2 Factor DOE Runs:
Tube LengthTube Length
Baffle SpaceBaffle Space
# Tube Passes# Tube Passes
Shell ID Shell ID
Shell MaterialShell Material
Tube ODTube OD
4 Critical Variables:4 Critical Variables:
Tube LengthTube Length
Baffle SpaceBaffle Space
Shell ID Shell ID
Tube ODTube OD
Opt
imiz
atio
Opt
imiz
atio
nn
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Each design variable is analyzed while everything else is kept constant
Variable Analysis
q_calc (W) Mass (kg) DP_Shell (Pa) DP_Tube (Pa)
variable Name 20% ↓ 20%↑ 20% ↓ 20% ↑ 20% ↓ 20% ↑ 20% ↓ 20% ↑
I_counter_flow 1.83E+07 5.22E+06 711.06 711.06 2.38E+08 2.38E+08 1.31E+05 1.31E+05
mdot_shell 2.43E+06 6.69E+06 710.77 711.24 1.58E+08 3.32E+08 1.31E+05 1.31E+05
Tube_length 4.17E+06 6.26E+06 568.85 853.28 1.89E+08 2.86E+08 1.07E+05 1.55E+05
Baffle_space 5.36E+06 5.09E+06 711.06 711.06 4.45E+08 1.44E+08 1.31E+05 1.31E+05
Tube_Thickness 5.17E+06 5.28E+06 684.28 748.57 2.38E+08 2.38E+08 1.05E+05 1.88E+05
N_tube_pass 2.59E+06 705.87 2.38E+08 9.48E+05
baffle_cut 5.22E+06 5.22E+06 711.06 711.06 2.38E+08 2.38E+08 1.31E+05 1.31E+05
Shell_id 4.05E+06 6.23E+06 456.96 1020.2 2.87E+08 2.04E+08 2.89E+05 6.95E+04
Shell_thickness 5.22E+06 5.22E+06 707.63 714.5 2.38E+08 2.38E+08 1.31E+05 1.31E+05
Shell_material 5.22E+06 5.22E+06 743.8 750.66 2.38E+08 2.38E+08 1.31E+05 1.31E+05
Tube_OD 6.75E+06 4.22E+06 745.51 686.69 3.08E+08 1.92E+08 2.37E+05 8.67E+04
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Effect of each variable on q_calc
1st run Main Effect Plots (11 Variables)
20
16000000
12000000
8000000
4000000
076.851.2 7.24.8
0.1615680.107712
16000000
12000000
8000000
4000000
00.00067080.0004472 10
I_counte_flow
Mean
mdot_shell Tube_length
Baffle_space Tube_Thickness N_tube_pass
Main Effects Plot for qCalcData Means
0.100980.06732
5200000
5150000
5100000
5050000
5000000
0.403920.26928 0.00120.0008
4121
5200000
5150000
5100000
5050000
5000000
0.00627840.0041856
baffle_cut
Mean
Shell_id Shell_thickness
Shell_material Tube_OD
Main Effects Plot for qCalcData Means
CUMMINS CONFIDENTIAL
Effect of each variable on DP_tube
1st run Main Effect Plots (11 Variables)
20
1000000
800000
600000
400000
200000
76.851.2 7.24.8
0.1615680.107712
1000000
800000
600000
400000
200000
0.00067080.0004472 10
I_counte_flow
Mean
mdot_shell Tube_length
Baffle_space Tube_Thickness N_tube_pass
Main Effects Plot for DPTubeData Means
0.100980.06732
480000
360000
240000
120000
00.403920.26928 0.00120.0008
4121
480000
360000
240000
120000
00.00627840.0041856
baffle_cut
Mean
Shell_id Shell_thickness
Shell_material Tube_OD
Main Effects Plot for DPTubeData Means
CUMMINS CONFIDENTIAL
Effect of each variable on DP_shell
1st run Main Effect Plots (11 Variables)
20
400000000
300000000
200000000
10000000076.851.2 7.24.8
0.1615680.107712
400000000
300000000
200000000
1000000000.00067080.0004472 10
I_counte_flow
Mean
mdot_shell Tube_length
Baffle_space Tube_Thickness N_tube_pass
Main Effects Plot for DPShellData Means
0.100980.06732
320000000
280000000
240000000
200000000
0.403920.26928 0.00120.0008
4121
320000000
280000000
240000000
200000000
0.00627840.0041856
baffle_cut
Mean
Shell_id Shell_thickness
Shell_material Tube_OD
Main Effects Plot for DPShellData Means
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Effect of each variable on weight_HE
1st run Main Effect Plots (11 Variables)
20
800
750
700
650
600
76.851.2 7.24.8
0.1615680.107712
800
750
700
650
600
0.00067080.0004472 10
I_counte_flow
Mean
mdot_shell Tube_length
Baffle_space Tube_Thickness N_tube_pass
Main Effects Plot for Weight_HEData Means
0.100980.06732
900
800
700
600
5000.403920.26928 0.00120.0008
4121
900
800
700
600
5000.00627840.0041856
baffle_cut
Mean
Shell_id Shell_thickness
Shell_material Tube_OD
Main Effects Plot for Weight_HEData Means
CUMMINS CONFIDENTIAL
Following variables were eliminated as a result of 1st DOE
I counter flow (We chose counter flow to Increase LMTD correction factor and heat exchanger effectiveness)
Baffle cut (We chose 84.15 mm)
Shell thickness (Only affects the weight, so we chose a reasonably thin shell)
Tube thickness (We chose a thickness of 0.559 mm)
mdot _shell (We chose a value of 64 Kg/m3 to minimize Dp_Shell.)
1st run Main Effect Plots (11 Variables)
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Effect of each variable on q_calc
2nd run Main Effect Plots (6 Variables)
7.24.8
4500000
4000000
3500000
3000000
2500000
0.1615680.107712 10
0.403920.26928
4500000
4000000
3500000
3000000
2500000
4121 0.00627840.0041856
Tube_length
Mean
Baffle_space N_tube_pass
Shell_id Shell_material Tube_OD
Main Effects Plot for qCalcData Means
CUMMINS CONFIDENTIAL
Effect of each variable on DP_tube
2nd run Main Effect Plots (6 Variables)
7.24.8
2000000
1500000
1000000
500000
00.1615680.107712 10
0.403920.26928
2000000
1500000
1000000
500000
04121 0.00627840.0041856
Tube_length
Mean
Baffle_space N_tube_pass
Shell_id Shell_material Tube_OD
Main Effects Plot for DPTubeData Means
CUMMINS CONFIDENTIAL
Effect of each variable on DP_shell
2nd run Main Effect Plots (6 Variables)
7.24.8
50000000
40000000
30000000
20000000
0.1615680.107712 10
0.403920.26928
50000000
40000000
30000000
20000000
4121 0.00627840.0041856
Tube_length
Mean
Baffle_space N_tube_pass
Shell_id Shell_material Tube_OD
Main Effects Plot for DPShellData Means
CUMMINS CONFIDENTIAL
Effect of each variable on weight_HE
2nd run Main Effect Plots (6 Variables)
7.24.8
900
800
700
600
5000.1615680.107712 10
0.403920.26928
900
800
700
600
5004121 0.00627840.0041856
Tube_length
Mean
Baffle_space N_tube_pass
Shell_id Shell_material Tube_OD
Main Effects Plot for Weight_HEData Means
CUMMINS CONFIDENTIAL
Variables Eliminated:Number of tube passes
We sacrificed some amount of heat transfer, however, we minimized the pressure drop, which implies that we can use less powerful pump.
Shell material We chose pure aluminum because:
It has a high thermal heat coefficient low weight. Fluid has same properties as water, therefore there is no
corrosion hazard.
2nd run Main Effect Plots (6 Variables)
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Effect of each variable on q_calc
3rd run Main Effect Plots (4 Variables)
7.24.8
6000000
5500000
5000000
4500000
40000000.1615680.107712
0.403920.26928
6000000
5500000
5000000
4500000
40000000.00627840.0041856
Tube_length
Mean
Baffle_space
Shell_id Tube_OD
Main Effects Plot for qCalcData Means
Tube_OD
Baffle_space
Shell_id
Tube_length
80706050403020100
Term
Standardized Effect
2.20
Pareto Chart of the Standardized Effects(response is qCalc, Alpha = 0.05)
CUMMINS CONFIDENTIAL
Effect of each variable on DP_tube
3rd run Main Effect Plots (4 Variables)
7.24.8
480000
360000
240000
120000
00.1615680.107712
0.403920.26928
480000
360000
240000
120000
00.00627840.0041856
Tube_length
Mean
Baffle_space
Shell_id Tube_OD
Main Effects Plot for DPTubeData Means
AD
A
D
5000004000003000002000001000000
Term
Effect
A Tube_lengthD Tube_OD
Factor Name
Pareto Chart of the Effects(response is DPTube, Alpha = 0.05)
CUMMINS CONFIDENTIAL
Effect of each variable on DP_shell
3rd run Main Effect Plots (4 Variables)
7.24.8
500000000
400000000
300000000
200000000
0.1615680.107712
0.403920.26928
500000000
400000000
300000000
200000000
0.00627840.0041856
Tube_length
Mean
Baffle_space
Shell_id Tube_OD
Main Effects Plot for DPShellData Means
BC
AB
BD
C
A
D
B
20151050
Term
Standardized Effect
2.31
A Tube_lengthB Baffle_spaceC Shell_idD Tube_OD
Factor Name
Pareto Chart of the Standardized Effects(response is DPShell, Alpha = 0.05)
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Effect of each variable on weight_HE
3rd run Main Effect Plots (4 Variables)
7.24.8
900
800
700
600
5000.1615680.107712
0.403920.26928
900
800
700
600
5000.00627840.0041856
Tube_length
Mean
Baffle_space
Shell_id Tube_OD
Main Effects Plot for Weight_HEData Means
D
AC
A
C
120100806040200
Term
Standardized Effect
2.2
A Tube_lengthC Shell_idD Tube_OD
Factor Name
Pareto Chart of the Standardized Effects(response is Weight_HE, Alpha = 0.05)
CUMMINS CONFIDENTIAL
Minitab Optimization
Critical Variables:
Tube Length Baffle Space Shell ID Tube OD
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Final Design Specifications
Tube Length = 6.06 m Baffle Space = 0.1616 m Shell ID = 0.2693 m Tube OD = 6.3 E-3 m Weight = 547.9 kg DP Shell = 238 MPa DP Tube = 45.44 KPa Q_Calc = 5,227 KW
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Conclusion
The Shell Pressure is high because we selected baffles
• Baffles induce turbulence which increases heat loss.
We chose a low Fouling factor of 3E-5: • The chemical has water like properties which
minimizes the likelihood of fouling.
We chose a 90° square pitch:• makes cleaning of the tubes easier
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Questions ?