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Aerospace, Vol. 11, Pages 1032: Numerical Investigation of Non-Equilibrium Condensation in a Supersonic Nozzle Based on Spontaneous Nucleation
Aerospace doi: 10.3390/aerospace11121032
Authors: Saman Javadi Kouchaksaraei Mohammad Akrami
Non-equilibrium condensation involves intricate physics, making it crucial to thoroughly investigate the factors that influence it. Understanding these factors is essential for optimizing the system performance and minimizing the negative effects associated with non-equilibrium condensation. This study focused on examining the impact of various operational conditions in a saturated mode on non-equilibrium condensation within a supersonic nozzle. The operation conditions under investigation involved pressures of 25 kPa, 50 kPa, 75 kPa, and 100 kPa. Each saturation state was examined to assess its effect on various parameters, such as temperature, pressure, liquid mass fraction, droplet radius, nucleation rate, Mach number, and droplet count. A consistent pattern emerged across all samples. As the gas accelerated through the converging section of the nozzle, both pressure and temperature gradually decreased. However, upon reaching the throat and entering the divergent section, a phenomenon known as condensation shock occurred. This shock wave caused a sudden and significant spike in both pressure and temperature. Following the shock, both parameters resumed their downward trend along the remaining length of the nozzle. Interestingly, increasing the initial pressure of the gas led to a less intense condensation shock. Additionally, raising the saturation pressure at the nozzle inlet resulted in larger droplets and a higher concentration of liquid within the gas flow. By quadrupling the inlet saturation pressure from 25 to 100 kPa, a substantial 106.9% increase in droplet radius and a 9.65% increase in liquid mass fraction were observed at the nozzle outlet.
