thermo mechanical behavior of heat exchangers
TRANSCRIPT
Thermo Mechanical Behavior of Heat Exchangers
A. Chidley, F. Roger, A. Traidia
ENSTA Paristech, France
COMSOL Conference 2010 Boston Presented at the
Thermo Mechanical Behavior of Heat Exchangers
• Aim of the study
• Thermal loading
• Mechanical behavior law
• ThM modeling of inlet critical zone
• Conclusion
Study
Thermal
Behavior
Results
Conclusion
Introduction
Study
Thermal
Behavior
Results
Conclusion
Radiator
Expansion tank
Engine
Water pump
Thermostatic valve
Thermoswitch
Heater core
Fan system
Ther
mal
sh
ock
Sketch of an automotive cooling system
Stress/Nb cycles curve
Introduction
Study
Thermal
Behavior
Results
Conclusion Study a tube with a periodic thermal shock loading
Usual automotive heat exchanger
Thermal loading
Real thermal field Study
Thermal
Behavior
Results
Conclusion
Fatigue experimental design
IR capture of selected points
Study
Thermal
Behavior
Results
Conclusion
Thermal loading
Time (s)
T/Tmax
Thermal field in a U-shaped heat exchanger
Dimensionless temperature at the inlet
Study
Thermal
Behavior
Results
Conclusion
Thermal loading
2 ways in Comsol Multiphysics
As a function, entered as a table
As a trigonometric function, time dependant
Mechanical behavior law
Study
Thermal
Behavior
Results
Conclusion
Follow damage
Fit cyclic tensile tests
Plasticity
Choice of hardening model
Cyclic tensile test
Mechanical behavior law Study
Thermal
Behavior
Results
Conclusion
Chaboche Elastoplastic behavior law
Thermoelasticity with plastic strain
02 3 2 .1p ptrace T T
plastic strain time evolution
Mechanical behavior law Study
Thermal
Behavior
Results
Conclusion
How to implement Chaboche Elastoplastic behavior law in Comsol Multiphysics
PDE General form module Solve hardening tensors
Use thermal structure module T, elastic
ThM modeling of the inlet critical zone
Study
Thermal
Behavior
Results
Conclusion
Quarter tube + collector
Thermal loading
Chaboche behavior
ThM modeling of the inlet critical zone
Study
Thermal
Behavior
Results
Conclusion
Thermal loading at the critical zone
ThM modeling of the inlet critical zone
Study
Thermal
Behavior
Results
Conclusion
Residual stresses at the end of the 10th cycle
ThM modeling of the inlet critical zone
Study
Thermal
Behavior
Results
Conclusion
Cumulated plastic strain
ThM modeling of the inlet critical zone
Study
Thermal
Behavior
Results
Conclusion
Cyclic stress vs strain
Study
Thermal
Behavior
Results
Conclusion
Energy based fatigue criterion
ThM modeling of the inlet critical zone
Conclusion
• Save time by entering thermal field
• Combined hardening model
• Good predictability
• Fatigue oriented design
Study
Thermal
Behavior
Results
Conclusion
Thankyou! Any questions…