Masters Theses

Date of Award

12-2001

Degree Type

Thesis

Degree Name

Master of Science

Major

Mechanical Engineering

Major Professor

Roy J. Schulz

Committee Members

Firouz Shahrokhi, Ahmad Vakili

Abstract

The purpose of this paper is to investigate the fluid dispersion pattern (patternation) of two air-blast type atomizers. Two air-blast type atomizers have been obtained from the Arnold Engineering Development Center (AEDC) in Tullahoma, TN. These atomizers are used to create liquid droplet clouds in altitude simulation and icing research test cells, to simulate adverse weather flow conditions. Simulation of adverse weather in the engine test cells and wind tunnels is of great importance to the aerospace industry, since flight in adverse weather represents both safety and performance concerns. The capability to simulate adverse weather conditions such as icing and mixed precipitation in a test environment is essential in determining the operational limits of aircraft flying in adverse weather conditions as well as in the development of both anti-icing and de-icing technology for aircraft. This paper describes supplemental research performed as part of the continuing research on generating mixed phase ducted flow for adverse weather simulation testing in ground test facilities at AEDC (AEDC-UTSI Task Order 99-06) by R. J. Schuiz [4]. The research covered herein is concerned with the near-field patternation of two air-blast type atomizers which have been used at AEDC in the icing research test cells. A brief discussion is presented concerning the atomization techniques available as well as the fundamental physical phenomena which characterize the atomization process. In this investigation, the spray patternation was determined for a variety of gas and liquid flow rates (or supply conditions), as well as at various axial flow cross-sections. The results of these experiments show the relationship between the Weber number and patternation (particle breakup and dispersion) The lower the liquid flowrate (higher Weber number), the greater the atomization . This is predicted through the Weber number, which relates the forces trying to break the water droplets apart (aerodynamic drag) to the forces trying to keep the droplet together (surface tension forces).

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