Methods Of Variability Reduction In Ramjet Fuel Injection Using Fluid-Structure Interactions

Author

Egan J. RigneyFollow

Keywords

Ramjet, Liquid Jet in Crossflow, Fuel Injection, Pintile, Fluid Structure Interactions

Abstract

The Liquid Jet in Crossflow (LJIC) method of fuel injection in ramjet engines is widely used and well-studied. However, they experience variation in their behavior at different altitudes and flight speeds due to the varied flow conditions following the inlet. This variation becomes more noticeable at high-temperature and high-speed airflow conditions. The optimized and consistent breakup of liquid fuel is a key component in ramjet engine design as there is a minimum surface area requirement of the droplets for combustion to occur. Local equivalence ratios also have a significant influence on the effectiveness of combustion. As such, researchers at the Propulsion and Energy Research Laboratory (PERL) have been developing injection methods to combat this. The design methodology for these injectors is to position a structure, called a pintile, above the injection orifice such that the liquid jet begins column breakup at the Fluid-Structure Interaction (FSI). This reduces the influence of aerodynamic forces on the breakup process of the LJIC.
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/="/">The present work studies the effects of two pintiles on reducing the variation of the windward trajectory and penetration height due to the change in momentum flux ratio and crossflow temperature. The two pintiles considered are triangular faced with a varied vertex angle (60-degree and 120-degree) at the FSI and are compared with a baseline case where a canonical LJIC is used. The mean image over one second of operation was found through binarization and cell detection image processing methods.
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/="/">The results of the experiment show that the inclusion of the pintiles standardizes the change in trajectory based on momentum flux ratio. Also, the change in trajectory based on temperature is shown to be reduced from that of the baseline case with the pintiles tested. While both pintiles showed positive results, the 120-degree pintile outperformed the 60-degree noticeably. To gain a better understanding of the effectiveness of pintile designs, more triangular-faced pintiles should be tested with more face angles, momentum flux ratios, and crossflow temperatures.

Thesis Completion Year

2025

Thesis Completion Semester

Spring

Thesis Chair

Ahmed, Kareem

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Thesis Discipline

Mechanical Engineering

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

STARS Citation

Rigney, Egan J., "Methods Of Variability Reduction In Ramjet Fuel Injection Using Fluid-Structure Interactions" (2025). Honors Undergraduate Theses. 308.
https://stars.library.ucf.edu/hut2024/308