The influence of condensation phenomena in expansion, with the action of a gas/vapor mixture on a piston

The expansion of a gas/vapor mixture acting on a piston is investigated analytically and experimentally, with a focus on the condensation process in the unsteady case. The fundamental equations are presented with the corresponding boundary conditions and reduced to a dimensional form prior to application of characteristic and finite-difference methods of solution. Experiments are performed in an apparatus comprising a high-pressure chamber filled with various gases or gas/water-vapor mixtures which is joined suddenly (by membrane rupture) to a tube containing a free piston. The results of theoretical calculations and experiments are compared in graphs, and good agreement is found. The applications to problems in astrophysics, particle physics, aerosols, energy production, aerodynamics, ballistics, and propulsion are indicated.