An Experimental Method for Locating Streamtubes in a Free Jet Expansion to Near Vacuum
Final rept. Jan-Nov 1968
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
Experimental investigations of free jet expansions into near vacuum conditions have in the past been generally limited to pressure, temperature, and force measurements. This investigation concerned a method of experimentally defining the streamtubes in a free jet expansion by splitting the flow along streamtubes with a series of diffusers operating in a cryogenically pumped vacuum chamber. Conditions necessary for shock attachment at the diffuser inlet were analyzed and streamtubes in a CO2 free jet expansion were experimentally determined. The procedure was found to be applicable for up to 98 percent of the plume mass flow if suitable diffuser inlet design is used. The method is ideally suited for streamtube definition in flows with entrained solids, for condensing flows, or for gaseous mixtures. For the free jet expansion investigated, qualitative information was derived concerning the effect of nozzle boundary layer on the plume expansion, the degree of condensation in the plume, and the applicability of method of characteristics solutions to the expansion process.
- Fluid Mechanics
- Rocket Engines