Heat Exchanger Design Optimization

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Heat Exchanger Design Optimization
ME 414 Thermal / Fluid System Design
Final Project Department of Mechanical
Engineering
Fall 2005
December 13, 2005
Team Members Kris Miller
Matt Obras Andrew Wall Ben
Warner
Professor John Toksoy
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Problem Statement

• Design a heat exchanger to reduce the temperature
  of a chemical by 10º Celsius with the following
  parameters
• Mass flow rate is 80,000 kg/hr.
• Fluid enters the heat exchanger at 35º C and
  should leave at 25º C.
• Material properties are approximated as water.
• Cooling of the chemical will be achieved by using
  treated water.
• City water is available at 20º C.
• Mass flow rate is adjustable.

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Goals

• Cool hot fluid by 10º Celsius
• Minimize costs by
• Minimizing weight
• Minimizing pressure drops
• Optimizing tube material

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Funnel Effect
7 Effecting Variables
3 Critical Variables

• Tube Outer Diameter
• Tube Thickness
• Shell Inner Diameter
• Shell Thickness
• Tube Length
• Tube Pitch
• Number of Tubes
• Number of Tube Passes
• Shell and Tube Material
• Use of Baffles
• Baffle Spacing
• Baffle Cut
• Shell Flow Rate
• Fluid Allocation
• Type of Flow
• Number of Passes

• Tube OD
• Shell ID
• Tube Length
• Number Passes
• Shell Mass Flow
• Rate
• Use of Baffles
• Baffle Space

• Tube OD
• Shell ID
• Tube Length

1 Factor Runs Engineering Judgment
2 Factor DOEs
Optimization
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Starting Point for Optimization Process
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Matlab DOE Minitab DOE Main Effects Plots7
Variables
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Matlab DOE Minitab DOE Main Effects Plots3
Variables
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Pareto Charts
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Minitab Design Optimization

• Key Parameter Changes
• Pressure Drop (Shell and Tube)
• Number of Tubes
• Weight

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Final Heat Exchanger Parameters
Results using nominal values based on Minitab
Optimization Fouling was taken into
consideration
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Conclusion

• Chemical was successfully cooled 10 C and met
  all specifications
• Cost minimized
• Low weight low material cost
• Low pressure drop lower operational cost

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Questions