Compressible flow of saturated moist air with condensation phenomena

Compressible flow of saturated moist air with various condensation processes around thin airfoils is investigated. The study uses an extended transonic small-disturbance (TSD) model of Rusak and Lee [11] which includes effects of heat addition to the flow due to condensation. Two possible limit types of condensation processes are considered. In the nonequilibrium and homogeneous process, the condensate mass fraction is calculated according to classical nucleation and droplet growth rate models. In the equilibrium process, the condensate mass fraction is calculated by assuming an isentropic process. The flow and condensation equations are solved numerically by iterative computations. Results under same upstream conditions describe the flow structure, field of condensate, and pressure distribution on airfoils' surfaces. It is found that flow characteristics, such as position and strength of shock waves and airfoils' pressure distribution, are different for the two condensation processes. Yet, in each case, heat addition as a result of condensation causes significant changes in flow behavior and affects the aerodynamic performance of airfoils.