Ragsdale, William C. | Search NASA

NASA NTRS1990

Condensation in hypersonic nitrogen wind tunnels

Experimental observations and a theoretical model for the onset and disappearance of condensation are given for hypersonic flows of pure nitrogen at M = 10, 14 and 18. Measurements include Pitot pressures, static pressures and laser light scattering experiments. These measurements coupled with a theoretical model indicate a substantial non-equilibrium supercooling of the vapor phase beyond the saturation line. Typical results are presented with implications for the design of hypersonic wind tunnel nozzles.

Lederer, Melissa A.↗

NASA NTRS1990

Condensation shocks in hypersonic nitrogen tunnels

Experimental observations and a theoretical model for the onset and disappearance of condensation are provided for hypersonic flows of pure nitrogen at M = 10, 14, and 18. A method for analyzing the thermodynamic and flow properties of a partially condensed mixture from known supply conditions and measured Pitot pressure yields the local static pressure and temperature, mass fraction of the nitrogen condensed, and the Mach number of the partially condensed flow based on frozen sound speed. The transition between partially condensed-supercooled flow is found to occur at 22-25 K isobaric supercooling with the corresponding mass fraction condensed being 12-14 percent over a range of two orders of magnitude in local static pressure. The heat released and vapor mass removed during condensation ultimately raise the local pressure and temperature and reduce the flow Mach number.

Hudson, Susan T.↗