Title: Heat Exchanger Design Project Department of Mechanical Engineering ME 414 Thermal / Fluid System Design Final Project December 13, 2005 Group Members: David Langenderfer Rishi Govalakrishnan Dan Langenderfer Vincent Liaw Professor: Mr. John Toksoy
1Heat Exchanger Design ProjectDepartment of
Mechanical EngineeringME 414 Thermal / Fluid
System DesignFinal ProjectDecember 13,
2005Group MembersDavid LangenderferRishi
GovalakrishnanDan LangenderferVincent
LiawProfessor Mr. John Toksoy
2Problem Statement
- Design a heat exchanger flowing a chemical at
80,000 kg/hr to drop the fluid temperature from
35C to 25C - Cooling chemical is city water flowing at 20C
- The shell may not exceed 2 meters in diameter and
7 meters in length - Weight, pressure drop, and cost should be
minimized
3Assumptions
- 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
4Matlab 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
5Funneling Effect
Tube OD, Shell ID, Length, Number of Passes, Tube
Material, Baffles, Baffle Spacing
7 Factors
3 Factors
Tube OD, Shell ID, Length
6Optimization
- 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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8Determining Effects on Heat Exchanger
- Key variables for an effective heat exchanger
- Tube OD
- Shell ID
- Tube Length
9Decisions 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
10Decisions Contd
- 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
11Optimization Plots
12Results
- 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
13Results (contd)
- ?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
14Lessons 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)
15References
- Heat Exchangers Selection, Rating, and
- Thermal Design
- KakaƧ and Liu
- CRC Press, 2nd Edition, 2002
- ME 414 Lecture Notes
- Professor John Toksoy, 2005
16Questions