Thermodynamic properties and explosion energy analysis of carbon dioxide blasting systems

ABSTRACT A carbon dioxide (CO2) blasting system is a reusable non-explosive blasting product that can be used in many engineering applications. To investigate the influences of thermodynamic properties of liquid CO2 and its explosion energy during the phase transition, the pressure within the blasting tube was measured in a laboratory for a liquid CO2 blasting system. Based on the measured pressure curve, the CO2 blasting process can be divided into three stages: pressure rising stage, pressure release stage and pressure recovery stage. The evolutions of temperature, pressure, phase transition and explosion energy of the CO2 blasting system were analysed in detail in this work. The results show that the variation rate of temperature increases as the initial density of CO2 decreases. The effect of initial CO2 density on its isochoric heat capacity is also significant as the lower the initial density, the higher the peak specific heat capacity at the critical temperature. Based on the Span and Wagner CO2 equation of state and the thermodynamics of explosions, a method is proposed to calculate the explosion energy of CO2 blasting systems. This method produces more accurate and realistic results.