Mechanical Behavior of Copper Multi-Channel Tube for HVACR Systems

by Lin Qi

Institution: Ohio University
Department: Mechanical Engineering (Engineering and Technology)
Degree: MS
Year: 2013
Keywords: Mechanical Engineering; Materials Science; Metallurgy; Analytical Model; CDA-122 DHP Copper; Constitutive Equation; Failure Pressure
Record ID: 2017982
Full text PDF: http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1381328798


The purpose of this research was to evaluate the mechanical behavior of extruded (UNS-C12200) copper multi-channel tube for HVACR (heating, ventilation, air conditioning and refrigeration) systems. A model was developed to predict the burst pressure of the copper tube. The assumption for the model is based on plane strain plastic deformation to an instant of instability where differential internal pressure is equal to zero. Physical simulations were used to develop a relevant microstructure that is representative of the tube in a manufactured heat-exchanger. To this end, cold rolling was used to simulate post-extrusion straightening and sizing of the tube. A subsequent thermal treatment was performed in a tube furnace to simulate a brazing thermal cycle. Tensile tests were conducted to obtain material data, and to determine material constants for a Voce type constitutive equation. Burst tests were conducted to validate the predictive model. Burst pressures were predicted to within 6% of measured values. The effects from cold working and the simulated brazing cycle were also evaluated in this research.