Keywords

Shock Waves, Liquid Fuels, Shock-Droplet Interaction, Pressure Gain Combustion, Detonations, Fluid Mechanics

Abstract

Understanding the deformation and aerobreakup of liquid droplets is critical for designing fuel injectors for pressure gain combustion systems. Previous literature has observed the morphology and timescales of individual liquid droplets exposed to the convective flow fields behind moving shocks propagating between Mach 1 and Mach 10. However, the liquid droplets produced by an injection system are not isolated and have many close neighbor droplets of similar diameter. Understanding interactions between these droplets is necessary to reconcile existing theory with droplet behavior observed in liquid jets and droplet clouds. The present study uses a simple injector to create vertically oriented droplet arrays of RP-2 and Jet A-1. The droplets had a mean diameter of 273 microns with a standard deviation of 52 microns. The spacing between droplets in these arrays was random and ranged from 1 to 4 droplet diameters. The displacement and breakup time of each droplet in the arrays were tabulated and compared against a nondimensional separation L/Do. The tests were performed in the shock Tube for HyperSonic Research at UCF’s propulsion and energy research laboratory. Testing was performed using normal shocks propagating at Mach 5.0, 6.6, and 7.5. It was found that vertical droplet spacing had little to no effect on droplet acceleration or breakup time, suggesting that horizontally oriented droplets may be responsible for any differences observed between individual droplet breakup and grouped droplet breakup.

Completion Date

2025

Semester

Spring

Committee Chair

Ahmed, Kareem

Degree

Master of Science (M.S.)

College

College of Engineering and Computer Science

Department

Department of Mechanical and Aerospace Engineering

Identifier

DP0029355

Document Type

Dissertation/Thesis

Campus Location

Orlando (Main) Campus

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