1. Purdue School of Engineering and Technology
Heat Exchanger Design Project Department of Mechanical Engineering ME 414 Thermal / Fluid System Design Final Project December 13, Group Members: David Langenderfer Rishi Govalakrishnan Dan Langenderfer Vincent Liaw Professor: Mr. John Toksoy
Purdue School of Engineering and Technology

2. Purdue School of Engineering and Technology
Problem Statement
Design a heat exchanger flowing a chemical at 80,000 kg/hr to drop the fluid temperature from 35°C to 25°C
Cooling chemical is city water flowing at 20°C
The shell may not exceed 2 meters in diameter and 7 meters in length
Weight, pressure drop, and cost should be minimized
Purdue School of Engineering and Technology

3. Purdue School of Engineering and Technology
Assumptions
Process and cooling fluid have minimal corrosive properties
Properties of fluid are similar to water
Counter flow to improve effectiveness
Tube pitch set at 90 degrees
Pitch ratio of 1.25 (rule of thumb)
Shell side mass velocity set to 140,000 kg/hr
Purdue School of Engineering and Technology

4. Matlab Implementation
Initially used to determine possible dimensions of an acceptable heat exchanger
Output from Matlab was inputted into Minitab for optimization
Compared results from Matlab output and Minitab optimization
Purdue School of Engineering and Technology

5. Purdue School of Engineering and Technology
Funneling Effect
Tube OD, Shell ID, Length, Number of Passes, Tube Material, Baffles, Baffle Spacing
7 Factors
3 Factors
Tube OD, Shell ID, Length
Purdue School of Engineering and Technology

6. Purdue School of Engineering and Technology
Optimization
Obtained results with 7 parameters from Matlab
Using DOE Factorial Response in Minitab we reduced the parameters by utilizing Main Effects plots
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7. Purdue School of Engineering and Technology

8. Determining Effects on Heat Exchanger
Key variables for an effective heat exchanger
Tube OD
Shell ID
Tube Length
Purdue School of Engineering and Technology

9. Decisions from Main Effects
Two pass on tube side:
Minimal foot print on shop floor
Minimize leak points
Increases pressure drop
Allows for independent expansion of tubes
and shell1
Purdue School of Engineering and Technology

10. Purdue School of Engineering and Technology
Decisions Cont’d
Counter flow is desirable for a two tube pass exchanger to increase effective temperature difference1
Aluminum minimized weight with no effect on heat transfer
No baffles due to large increase in pressure drop on shell side
Purdue School of Engineering and Technology

11. Purdue School of Engineering and Technology
Optimization Plots
Purdue School of Engineering and Technology

12. Purdue School of Engineering and Technology
Results
Tube OD: m
Shell ID: m
Length: 3.0 m
Tube velocity: 1.54 m/s (Range m/s)
Turbulent flow promoting high heat exchange on shell and tube
Heat transfer is 6% over desired heat transfer to accommodate for future fouling
Purdue School of Engineering and Technology

13. Purdue School of Engineering and Technology
Results (cont’d)
ΔP Shell: 2,513 Pa ( PSI)
ΔP Tube: 38,450 Pa (5.577 PSI)
Weight: 496 kg (1094 lbs)
Number of Tubes: 750
Purdue School of Engineering and Technology

14. Purdue School of Engineering and Technology
Lessons Learned
Optimization using interaction between Minitab and Matlab
How to work as a team
Lots of decisions to make when given an open ended question
Many solutions to a simple problem
Finish projects early (12/4/2005)
Purdue School of Engineering and Technology

15. Purdue School of Engineering and Technology
References
Heat Exchangers Selection, Rating, and
Thermal Design
Kakaç and Liu
CRC Press, 2nd Edition, 2002
ME 414 Lecture Notes
Professor John Toksoy, 2005
Purdue School of Engineering and Technology

16. Purdue School of Engineering and Technology
Questions
Purdue School of Engineering and Technology