Electrothermal discharge by exploding of copper wires with different diameters

Abstract

Abstract This paper explores the explosion behavior of copper wires with diameters between 0.16 mm and 0.50 mm, using an electrothermal discharge system comprising capacitors of total energy up to 1.11 kJ. To improve accuracy, this study incorporates the effects of thermal expansion, resistivity, specific heat capacity, and phase transformation. The variations of the different electrical properties of the copper wires were calculated as a function of the discharge time, wire temperature, and wire diameter. The temperature profile for copper was based on the melting point (1357 K) and boiling point (2835 K). The Shomate equation was used to calculate the specific heat capacity of the copper wires as a function of temperature; while the wire resistivity was determined using a fitting equation based on previous published data. The results indicate that the time needed for wire explosion decreases for the higher charging voltage, while it increases with larger wire diameter. The thermal expansion shows a 9.95% increase in length and a 19.9% increase in cross sectional area. Additionally, as the discharge occurs, the wire temperature rises, causing an increase in both of the specific heat and the wire resistivity. Furthermore, the specific action integral converges to a constant value of approximately 2.1 × 10 9 A 2  s/cm 4 for all diameters.