The Evaporation of Liquid Droplets in Highly Turbulent Gas Streams

Abstract

Single acetone and heptane droplets were suspended from a hypodermic needle in turbulent airflow, and the Nusselt number was obtained from direct measurements of the droplet diameter and evaporation rate. Acetone was selected because it fluoresces when irradiated with ultraviolet laser radiation while heptane was selected because of its high volatility compared with water, methanol, and ethanol which were used previously. Planar laser induced fluorescence (PLIF) measurements were made to obtain qualitative concentration measurements of gaseous acetone in the boundary layer surrounding the droplet. The goal of these measurements was to give insight as to why the evaporation rate is increased by 50 % when the gas phase turbulence is increased from the laminar flow case to the case where the freestream turbulence is 10%. The use of acetone droplets required that the influence of humidity on droplet evaporation rate be considered. Measurements of the turbulence intensity of heated freestream air were also made. Finally, many modifications to improve the experimental apparatus were made during this research project.

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Document Details

Document Type
Technical Report
Publication Date
May 31, 1998
Accession Number
ADA365207

Entities

People

  • Richard D. Gould

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Materials and Manufacturing Processes
  • Space

DTIC Thesaurus Topics

  • Air Flow
  • Alcohols
  • Boundaries
  • Boundary Layer
  • Engineering
  • Evaporation
  • Flow
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Flow
  • Laminar Flow
  • Laser Induced Fluorescence
  • Lasers
  • Layers
  • Mass Transfer
  • Measurement
  • Methanols

Fields of Study

  • Physics

Readers

  • Aerosol Science/Aerosol Physics
  • Analytical Chemistry
  • Fluid Dynamics.

Technology Areas

  • Directed Energy
  • Directed Energy - Pulsed-Laser Deposition