ME 414 Thermal / Fluid System Design Heat Exchanger Project

1. Department of Mechanical Engineering ME 414 Thermal / Fluid System DesignHeat Exchanger Project Professor: John Toksoy 12/13/05 Fall 2005 Final Project Team Members: Chester Bennett Wilton Green Scott Guttman Nick Miller

2. 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

3. 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

4. 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 Potential Key Parameters Consideration Criterion: Heat Transfer, Pressure Drops, Weight, Cost

5. Non-potential Parameter Judgements • Pitch Type • Square Pitch • Tube Layout • 90 degree layout • Flow Type • Counter Flow • Baffle Design • Provides turbulence to reduce fouling

6. Shell Material Selection • Material Considerations • Weight • Heat Transfer Rates • Strength and Stress • Corrosion Resistance • Cost (Initial and Maintenance) • Stainless Steel • Carbon Steel • Stainless Steel AISI 304 • Pure Bronze • Pure Copper • Pure Aluminum Decision rational: • Aluminum is light weight • Aluminum is a good heat conductor • Aluminum is compatible with water • Aluminum low yield stress not a factor • Aluminum’s benefits justify the costs

7. 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

8. Main Effects Plots

9. Variable Reduction • 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 - Aluminum - .001254 m

10. Main Effects Plots for 4 Key Parameters

11. Original Optimization • Optimization Setup • Optimization Results • Optimization Results Chart

12. Optimization Considerations • Standardizing parameters to minimize costs • Tube OD • Shell ID - .0127 meters - .2540 meters, .3048 meters, or .3366 meters • Varying parameter’s 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

13. Optimization Results Option 1 Option 2 Option 3

14. 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 http://www.greenheck.com/technical/files/Product_guide/images/pag_fig5.gif

15. From Alpha to Omega Heat Exchanger Option 1

16. Questions