http://fluxtrol.com

1. Computer Assisted Induction
Aluminum Brazing
R. C. Goldstein, V. S. Nemkov, R. T. Ruffini
Centre for Induction Technology, Inc.
www.induction.org
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2. Overview
• Automotive Heat Exchangers
• Pipe to Tube Brazing
• Computer Simulation of Induction Brazing
of Pipe to Tube Joints
• Optimization of Induction Coil
• Conclusions
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3. Automotive Heat Exchangers
• Used for thermal
management in many
areas of the car
– Oil Coolers
– Powertrain
– Air Conditioning
– Dehumidifiers
– etc.
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4. Heat Exchanger Manufacturing
• Assembling of heat exchanger bodies
• Brazing of body in a controlled atmosphere
furnace
• Attachment of various components for
connection to different cars
– Nylon tanks
– Aluminum pipes with connection blocks (most
common)
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5. Pipe to Tube Brazing
• Clamshell Inductors
– Problems with electrical
contacts
– Complicated mechanical design
• “Horseshoe-Hairpin”
Inductors
– Non-uniform heating in
circumference
– Complicated magnetic field
distribution
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6. Pipe to Tube Induction Brazing Installation
using “Horseshoe-Hairpin” Coil
Connection Block
Pipe
Joint
Fluxtrol A Magnetic
Flux Controller
Copper Coil
Tube
Header
Body
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7. Computer Simulation of Pipe to
Tube Brazing
• Not possible to simulate all processes due to
process complexity
• 2-D approach can not be used for
Horseshoe-Hairpin inductors
• 3-D electromagnetic simulation used to
study heat sources (most controllable factor)
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8. 1/4 of a Heat Exchanger Brazing
Coil
Pipe
Tube
Fluxtrol A Magnetic
Flux Controller
Copper Coil
Heat Exchanger
Header
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9. Main Variables in this System
• Coil and Concentrator Dimensions
• Coil Position
• Contact in the Brazing Joint
• Coil Crossover
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10. Different Crossovers
+ + + .
. . . +
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11. Existing Induction Coil with
Diagonal Crossover
No Contact Good Contact
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12. Existing Induction Coil with
Horizontal Crossover
No Contact Good Contact
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13. Current Density Distribution for
Optimized Induction Coil
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14. New Induction Coil
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15. Conclusions
• Induction aluminum brazing of heat exchanger
joints can be a very complicated process
• 3-D computer electromagnetic simulation
provided good information regarding the heating
process
• Optimized induction coil and process was more
robust and produced higher quality joints
• Further study should be made using 3-D coupled
electromagnetic plus thermal simulation
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