Prediction of supersonic condensation process of methane gas considering real gas effects

To clarify the condensation characteristics of natural gas under a high pressure and obtain accurate nucleation parameters, traditional Internal Consistent Classical Nucleation Theory (ICCT) model for single-component gas was improved. A mathematical model for the supersonic condensation flow of methane gas was established based on the improved ICCT model, and the supersonic condensation process was experimentally verified. The field characteristics of condensation flow and isentropic flow were compared, and the low-temperature liquefaction characteristics of methane gas in the Laval nozzle were studied. The results show that the calculation results of improved model considering the real gas effect are more accurate than the results of original ICCT model. When methane gas is condensed, a weak condensation shock wave propagates in the nozzle; compared with the isentropic expansion process, the pressure and temperature at nozzle outlet increase. In a very short distance, the nucleation rate of methane gas sharply increased from 0 to a maximum value of 4.834 x 10(21) m(-3) s(-1) (approximately at x = 0.367 m). The maximum droplet radius, droplet number, and liquid mass fraction are 2.112 x 10(-7) m, 4.128 x 10(14) kg(-1), and 5.437%, respectively.