Worcester Polytechnic Institute Electronic Theses and Dissertations Collection

Title page for ETD etd-051199-174419


Document Typethesis
Author NameNewman, Aaron W.
Email Address NewmanAW at navair.navy.mil
URNetd-051199-174419
TitleThe Effect of Superheat on Liquid Droplets in a Supersonic Freestream
DegreeMS
DepartmentMechanical Engineering
Advisors
  • Dr. James C. Hermanson, Advisor
  • Dr. David J. Olinger, Committee Member
  • Dr. Nikolaos A. Gatsonis, Committee Member
  • Dr. William W. Durgin, Committee Member
  • Keywords
  • droplet injection
  • supersonic crossflow
  • superheat
  • droplet disruption
  • Date of Presentation/Defense1999-04-02
    Availability unrestricted

    Abstract

    The effect of superheat on the disruption of liquid droplets in a compressible gas flow was investigated experimentally in a small-scale, supersonic wind tunnel. Aerodynamically generated ethanol droplets of an average diameter of 0.1 mm were injected via a normal sonic jet into a Mach 1.8 freestream. Both nonsuperheated and superheated droplets were injected with initial Weber numbers of approximately 700. The droplets and flow structure were photographed using the shadowgraph method. The relatively high momentum of the liquid droplets typically caused them to pass out of the sonic jet structure. Nonsuperheated droplets showed no signs of disrupting after traveling over 200 mm downstream from the injection point. Only droplets with injection temperatures above the predicted boiling point at tunnel freestream static pressure (48°C) showed signs of disruption, typically after they left the sonic jet structure (30 to 100 mm downstream of the injection point). Droplets in this range of temperatures appeared to begin to boil from the downstream side of the droplet, shedding a vapor cloud before disrupting completely in the chaotic mode. Droplets with temperatures above the boiling point at the exit plane of the sonic jet began to disrupt in the chaotic mode almost instantly (within 1 exit nozzle diameter).

    Files
  • newman.pdf

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