heat exchanger design
DESCRIPTION
Heat Exchanger Design. ME 414- Fluid Systems Design Professor: John Toksoy Spring 2009 team Tyler Laughlin Denis Shkurapet Ethan Sneed Matt Tolentino Tyler Turk. Objective. To design a heat exchanger than meets the following criteria: Cools liquid from 45 C to 25 C - PowerPoint PPT PresentationTRANSCRIPT
ME 414- FLUID SYSTEMS DESIGNPROFESSOR: JOHN TOKSOYSPRING 2009TEAM
• Tyler Laughlin• Denis Shkurapet• Ethan Sneed• Matt Tolentino• Tyler Turk
Heat Exchanger Design
Objective
To design a heat exchanger than meets the following criteria:
Cools liquid from 45 C to 25 C Must be less than 7 meters in length Shell diameter is less than 2 meters Minimize weight of the tube and shell Minimize pressure drop Heat transfer ratio of 1
Design Parameters
# of tubes passedTube outer diameterTube inner diameterMaterialBafflesShell thicknessShell MaterialStrength factorsFluid allocationType of flow (parallel or counter)
Analysis
Use Minitab and Matlab
Minitab Use to obtain the main effects plots, Pareto charts, and
the response optimizer.
Matlab Use to run analysis of the DOE files and to give us the
outputs of total weight, calculated heat transfer, cost, and pressure drops.
DOE allows us to determine the most important variables in this design.
Results
Variable Initial value Final Value Explanations
Shell fluid Water Water Given Input
Tube fluid Chemical (water prop) Chemical (water prop) Given Input
M-dot shell 3.45 kg/s 3.9117 kg/sDOE - Optimizer suggested value
Mdot tube 61.11 kg/s 61.11 kg/sGiven value -tube selected for cleaning
T shell in 20°C 20°C Given Input
T tube in 45°C 45°C Given Input
T tube out 25°C 25°C Given Input
Rf tube in .00018 m²K/W .00018 m²K/W Reference value for water
Rf tube shell side .00018 m²K/W .00018 m²K/W Reference value for water
Flow config Parallel ParallelDOE - Optimizer suggested using parallel
# tube pass 1 1The program only allows one pass
# shell pass 1 1 For minimal weight
Results
Baffles No baffles No bafflesTo reduce weight/pressure drop
Shell ID 0.3366 0.3366DOE - Optimizer suggested no change
Shell Th 1.00E-03 1.00E-03DOE - Optimizer suggested no change
Shell Mat'l Stainless Steel 304 Stainless Steel 304Corrosion Resistant/ease of cleaning
Tube Mat'l Stainless Steel 304 Stainless Steel 304Corrosion Resistant/ease of cleaning
Nusselt Shell Dittus Boelter Dittus Boelter Most basic correlation
Nusselt Tube Gnielinski Gnielinski accounts for entrance effects
Pressure Corr Shell Default from textbook Default from textbookOnly option that was applicable
Pressure Corr Tube Default from textbook Default from textbookOnly option that was applicable
Tube OD 6.35e-3 m 6.35E-03DOE - Optimizer suggested no change
Tube Th .711e-3 m 4.57E-04DOE- Optimizer suggested value
Tube Length 2.00 1.85DOE- Optimizer suggested value
Tube Layout Angle 90 90DOE - Optimizer suggested no change
Results
Outputs Initial value Final Value Difference Units
T shell out 353.59°C 318.76°C 34.83 °C
# of tubes 1313 1313 0U (Heat Transfer
Coeff.) 828.48 W/m2.C 876.97 W/m2.C -48.49 W/m2.C
R value 1.00 0.98 0.02
Weight_He 411.21 350.88 kg 60.33 kg
DP Shell 267.89 Pa 335.11 Pa -82.99 Pa
DP Tube 45310.96 Pa 29832.58 Pa 15478.38 Pa
Analysis: 1st DOE
CounterParallel
700
500
300
4.31252.5875 2.51.5
0.0012500.000533
700
500
300
0.420750.25245 0.00128750.0007500
0.007930.00476
700
500
300
Flow
Mean
M dot Tube Length
Tube th Shewll ID Shell Th
Tube OD
ME 414 Main Effects Plot: Weight_HE
CounterParallel
1000000
500000
0
4.31252.5875 2.51.5
0.0012500.000533
1000000
500000
0
0.420750.25245 0.00128750.0007500
0.007930.00476
1000000
500000
0
Flow
Mean
M dot Tube Length
Tube th Shewll ID Shell Th
Tube OD
ME 414 Main Effects Plot: DP Tube
CounterParallel
1000
500
0
4.31252.5875 2.51.5
0.0012500.000533
1000
500
00.420750.25245 0.00128750.0007500
0.007930.00476
1000
500
0
Flow
Mean
M dot Tube Length
Tube th Shewll ID Shell Th
Tube OD
ME 414 Main Effects Plot: DP Shell
CounterParallel
10000000
7500000
5000000
4.31252.5875 2.51.5
0.0012500.000533
10000000
7500000
5000000
0.420750.25245 0.00128750.0007500
0.007930.00476
10000000
7500000
5000000
Flow
Mean
M dot Tube Length
Tube th Shewll ID Shell Th
Tube OD
ME 414 Main Effects Plot: Q Calc
Analysis: Pareto Charts 1st DOE
ABD
BD
AD
AB
D
AC
B
C
A
16000001400000120000010000008000006000004000002000000
Term
Standardized Effect
2
A FlowB M dotC Tube LengthD Tube th
Factor Name
Pareto Chart of the Standardized Effects(response is Weight, Alpha = 0.05)
AC
BC
C
AB
A
B
200150100500
Term
Standardized Effect
2.0
A FlowB M dotC Tube Length
Factor Name
Pareto Chart of the Standardized Effects(response is DP Shell, Alpha = 0.05)
Flow
Tube Length
14121086420
Term
Standardized Effect
1.98
Pareto Chart of the Standardized Effects(response is DP Tube, Alpha = 0.05)
BC
B
C
6050403020100
Term
Standardized Effect
1.98
B M dotC Tube Length
Factor Name
Pareto Chart of the Standardized Effects(response is Q Calc, Alpha = 0.05)
Analysis: 1st Optimization
Minitab solved for a local solution.
The starting values were changed multiple times until Minitab found a new, more optimal solution.
Analysis: 2nd DOE
CounterParallel
10000000
7500000
5000000
4.31252.5875 2.51.5
0.00057130.0003430
10000000
7500000
5000000
0.420750.25245 0.00128750.0007500
0.007930.00476
10000000
7500000
5000000
Flow
Mean
Mdot Tube Length
Tube Thick Shell ID Shell Thick
Tube OD
ME 414 Main Effects Plot Optimization 2: Q Calc
CounterParallel
150000
100000
50000
4.31252.5875 2.51.5
0.00057130.0003430
150000
100000
50000
0.420750.25245 0.00128750.0007500
0.007930.00476
150000
100000
50000
Flow
Mean
Mdot Tube Length
Tube Thick Shell ID Shell Thick
Tube OD
ME 414 Main Effects Plot Optimization 2: DP Tube
CounterParallel
1000
500
04.31252.5875 2.51.5
0.00057130.0003430
1000
500
00.420750.25245 0.00128750.0007500
0.007930.00476
1000
500
0
Flow
Mean
Mdot Tube Length
Tube Thick Shell ID Shell Thick
Tube OD
ME 414 Main Effects Plot Optimization 2: DP Shell
CounterParallel
700
500
300
4.31252.5875 2.51.5
0.0012500.000533
700
500
300
0.420750.25245 0.00128750.0007500
0.007930.00476
700
500
300
Flow
Mean
M dot Tube Length
Tube th Shewll ID Shell Th
Tube OD
ME 414 Main Effects Plot: Weight_HE
Analysis: 2nd Optimization
Starting values of the optimization were varied with no improvement in performance.
Conclusions: Damn near perfect!
Heat Transfer Coeff : 876.97 W/m2.C
R-value: 0.98Number of tubes: 1313Shell Pressure Loss: 335.11 PaTube Pressure Loss: 29832.58 PaWeight of Heat Exchanger: 350.88
kg
Conclusions: Recommendations
Could be further optimized if Tube Thickness was decreased
Resulting in: Lower weight - decrease of 51.93 kg Lower Tube pressure loss - decrease of 6703.1 Pa No significant loss of R-value
A smaller tube is not commercially availablePossibly achieve greater performance at a
greater price
Questions