NUMERICAL METHOD FOR DESIGNING A TWO-DIMENSIONAL DE LAVAL NOZZLE FOR OPTIMIZATION IN ASSISTED MACHINING WITH SUPERCRITICAL CO2

The purpose of this work is to present a quick method for designing the divergent section of planar Laval micro-nozzles in order to predict the properties of the CO2 jet at the nozzle and better control the cooling effect in the context of cryogenic machining with supercritical CO2 (ScCO2). The Method of Characteristics (MOC) and a real gas model have been implemented to obtain 2D nozzles divergent part adapted for single-phase gas expansion. CO2 inlet pressure, inlet temperature, and pressure distribution along the nozzle axis are set as input parameters. A 2D nozzle facility has been developed to allow visualization of the CO2 jet and its expansion in ambient air. Preliminary results are presented to demonstrate the potential of the facility.