No description available.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 46-47). Also available via the Internet.

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keyword: droplet. Includes bibliographical references (p. 42-45).

No description available.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: droplet injection; supersonic crossflow; superheat; droplet disruption. Includes bibliographical references (leaves 72-75).

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering 2016 / The nozzle contour profiles of the CSIR’s supersonic wind tunnel (high speed wind tunnel) were designed to produce smooth, uniform and shock-free flow in the operating section of the facility. The existing profiles produce weak waves in the test section region which induces flow gradients and flow angularities in the air flow, effectively degrading the air flow quality, which in turn perturbs the wind tunnel data. The wind tunnel geometry and tunnel constraints were employed in accordance with the method of characteristics technique to design the supersonic nozzle profiles. The Sivells’ nozzle design method was deemed the most feasible which calculates the profile downstream of the inflection point. The throat block profile was amalgamated with this profile to yield a profile from the throat to the test section. A boundary layer correction was applied to the profiles to account for viscous effects which cause a Mach number reduction from the desired test section Mach number. An automatic computation was used for the profile design and a computational method analysed the Mach distribution, flow angularity and density gradient (to determine the occurrence of shocks and expansions) of the profiles implemented in the tunnel, for the full Mach number range of the HSWT. The methods used, achieved uniform and shock-free flow such that the Mach number and flow angularity were within the acceptable quality limits of the HSWT.

The effects of liquid superheat on the disruption of liquid droplets accelerated in a supersonic flow were examined experimentally in a drawdown supersonic wind tunnel. Monodisperse 60 ìm diameter droplets of two test fluids (methanol and ethanol) were generated upstream of the entrance to the tunnel and accelerated with the supersonic flow such that their maximum velocities relative to the air flow were transonic. Droplets were imaged by shadowgraphy and by multiple-exposure direct photography using planar laser sheet illumination. In addition to providing information on droplet lifetime, the latter technique allows measurement of the droplet downstream distance versus time, from which the velocity and acceleration during disruption can be inferred. All droplets were unheated upon injection. Depending on the vapor pressure of the liquid, the droplets achieved varying levels of liquid superheat as they experienced low static pressure in the supersonic flow. Histograms of the droplet population downstream of the supersonic nozzle throat indicate that the lifetime of droplets in supersonic flow decreases with an increasing amount of droplet superheat. The shorter lifetime occurs even as the droplet Weber number (based on initial droplet size) decreases initially due to the lower relative velocity of the methanol droplets to that of ethanol droplets. This is due to a higher acceleration than ethanol droplets of comparable initial size. This is consistent with the more rapid disruption and the faster decrease in mass for the methanol droplets. The droplets, depending on the level of superheating, in some cases underwent disruption modes different than those expected for the corresponding values of Weber number.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: infrared spectroscopy; aerosols; nucleation; tunable diode laser; condensation; supersonic nozzles. Includes bibliographical references (p. 73-76).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 72-74). Also available via the Internet.