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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?CCooling chemical is city water flowing at 20?CThe shell may not exceed 2 meters in diameter and 7 meters in lengthWeight, pressure drop, and cost should be minimized.
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1. Purdue School of Engineering and Technology Heat Exchanger Design ProjectDepartment of Mechanical EngineeringME 414 Thermal / Fluid System DesignFinal ProjectDecember 13, 2005Group Members:David LangenderferRishi GovalakrishnanDan LangenderferVincent LiawProfessor: Mr. John Toksoy
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
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
4. Purdue School of Engineering and Technology 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
5. Purdue School of Engineering and Technology Funneling Effect
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
7. Purdue School of Engineering and Technology
8. Purdue School of Engineering and Technology Determining Effects on Heat Exchanger
9. Purdue School of Engineering and Technology 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
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
11. Purdue School of Engineering and Technology Optimization Plots
12. Purdue School of Engineering and Technology Results Tube OD: 0.0095 m
Shell ID: 0.3874 m
Length: 3.0 m
Tube velocity: 1.54 m/s (Range 0.9 - 2.4 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
13. Purdue School of Engineering and Technology Results (cont’d) ?P Shell: 2,513 Pa ( 0.365 PSI)
?P Tube: 38,450 Pa (5.577 PSI)
Weight: 496 kg (1094 lbs)
Number of Tubes: 750
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)
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
16. Purdue School of Engineering and Technology Questions