Abstract: The aerodynamic characteristics of airfoil are significantly influenced by non-equilibrium condensation of moist air. Based on the Fluent software, a new algorithm is developed to simulate the moist air flow with non-equilibrium condensation. Numerical simulation is implemented to investigate the condensing flow of moist air around the NACA0012 airfoil at 0° and 1.5° angles of attack respectively. Results show that compared with the dry air flow, the lift coefficient decreases obviously whereas the drag coefficient may increase or decrease at the relative humidity of 30%-70%. At 0° angle of attack, a maximum drag increase of 68.3% is observed. At 1.5° angle of attack, a maximum lift decrease of 39.8% and a maximum drag decrease of 34.8% are found out. The mechanism leading to the significant change of aerodynamic characteristics of airfoil is analyzed. With the condensation of water vapor in moist air, latent heat is released and added to the surrounding transonic air flow. As a result, the velocity, pressure and flow field structure of the moist air flow are significantly changed.

Key words: airfoils, moist air, condensation, aerodynamic characteristics, numerical investigation