ME 414 Thermal Fluid System Design Heat Exchanger Project

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ME 414 Thermal / Fluid System DesignHeat
Exchanger Project
Department of Mechanical Engineering
Fall 2005 Final Projec
t

• Professor John Toksoy
• 12/13/05

Team Members Chester Bennett
Wilton Green
Scott Guttman
Nick Miller
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Project Statement Challenges

• Challenge of the project to use an oriented and
  rational process to lead to a justified final
  design.
  
• Challenge of designing and optimizing a heat
  exchanger to particular qualifications
  
• Qualifications

• Tube side fluid is available at 20 C
• Tube side Mass flow rate is 22.22 kg/s
• Maximum tube length of 7 meters

• Maximum shell diameter of 2 meters
• Cool tube side fluid from 35oC to 25oC
• Tube and Shell fluid properties Water

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Objective

• Objective Definition
• Obtain a heat transfer ratio of 1
• Minimize pressure drop
• Minimize weight
• Minimize cost
• Achieving Objective Design Plan
• Determine potential key parameters
• Reduce key parameters to as few as possible prior
  to optimization using Matlab and Minitab
  
• Optimize using the DOE in Matlab and analyzing
  the results in Minitab
  

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Potential Key Parameters

• Shell Mass Flow Rate
• Shell Inner Diameter
• Shell Thickness
• Shell Material
• Type of Flow
• Pitch Type

• Tube Length
• Tube Outer Diameter
• Tube Thickness
• Tube Material
• Tube Layout Angle
• Tube Passes

Consideration Criterion Heat Transfer, Pressure
Drops, Weight, Cost
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Non-potential Parameter Judgements

• Pitch Type
• Square Pitch
• Tube Layout
• 90 degree layout
• Flow Type
• Counter Flow
• Baffle Design
• Provides turbulence to reduce fouling

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Shell Material Selection

• Stainless Steel
• Carbon Steel
• Stainless Steel AISI 304

• Pure Bronze
• Pure Copper
• Pure Aluminum

• Material Considerations
• Weight
• Heat Transfer Rates
• Strength and Stress
• Corrosion Resistance
• Cost (Initial and Maintenance)

• Decision rational
• Aluminum is light weight
• Aluminum is a good heat conductor
• Aluminum is compatible with water
• Aluminum low yield stress not a factor
• Aluminums benefits justify the costs

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Design of Experiment

• Using 6 key parameters
• Tube OD
• Tube Length
• Shell ID
• Mass Flow Rate
• Tube Material
• Tube Thickness
• Determine 15 range of chosen parameters
• Incorporate into DOE program in MATLAB
• Export output file to Minitab
• Obtain Main Effects Plots

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Main Effects Plots
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Variable Reduction
- Aluminum

• Establish material
• Establish tube thickness
• Establish 4 key parameters
• Tube OD
• Tube Length
• Shell ID
• Mass Flow Rate
• Determine 15 range of chosen parameters
• Incorporate into DOE program in MATLAB
• Export output file to Minitab
• Obtain Main Effects Plots

- .001254 m
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Main Effects Plots for 4 Key Parameters
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Original Optimization

• Optimization Setup

• Optimization Results Chart

• Optimization Results

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Optimization Considerations

• Standardizing parameters to minimize costs
• Tube OD
• Shell ID

- .0127 meters
- .2540 meters, .3048 meters, or .3366 meters

• Varying parameters current optimum value (red
  line)
  
• Effect Increasing or decreasing Output values
  according to slope
  
• Effect Increasing or decreasing Output
  desirability value
  
• Goal To keep standardized parameters
• Goal To maintain heat transfer ratio of 1
  (desirability of .7-.8)
  
• Goal Minimize Outputs considering importance of
  Outputs
  
• Sacrificing Weight or Pressure Drop

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Optimization Results
Option 1
Option 2
Option 3
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Final Project Conclusion

• Option One Decision Criteria
• Equal heat transfer ratios among all Options
• Safe fouling velocity in tube
• Standardized tube and shell sizes
• Trade-offs in relative percentage gains and
  losses
  
• Precedence to pressure

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uide/images/pag_fig5.gif
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From Alpha to Omega
Heat Exchanger Option 1
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Questions