Theoretical and experimental investigation of the condensation zone in a supersonic nozzle flow

The process of homogeneous condensation and the resulting formation of condensation nuclei is investigated analytically and experimentally, considering the supersonic nozzle flow of a gas/steam mixture with a high steam content. The flow and condensation equations are joined in a system of coupled differential equations permitting the determination of the density gradient and other experimentally measurable parameters from given nozzle configuration and initial conditions. The experimental setup includes a closed Ludwieg-tube wind tunnel with a membrane separating the supply tube from the nozzle (until initiation of the run) and a laser differential interferometer to measure density gradients by means of Mie scattering. The results are presented graphically, and factors affecting the degree of agreement between calculated and measured flow and condensation parameters are analyzed.