Current EPRL Projects

Energy Efficiency: Transverse Jet Instabilities & Control

This project involves examination of the fundamental features of the pulsed or acoustically excited transverse jet, a flowfield which may be applied to fuel injection as well as dilution air injection in gas turbine engines, and thrust vectoring for high speed vehicles, and which can potentially be controlled via active means so as to improve engine efficiency and reduce emissions. Current activities involve vortex element simulations…[more]

Advanced Propulsion: Detonations, Ionized Gas Simulations, and Turbulent Combustion

This computational study examines transient, reactive compressible flow phenomena associated with the pulse detonation engine. The PDE is an intermittent combustion engine that relies on unsteady detonation wave propagation for combustion and compression elements of the propulsive cycle…[more]

Alternative Fuels: Acoustically Coupled Droplet Combustion Control

This study focuses on quantifying and understanding the effects of external acoustical perturbations on condensed phase combustion processes. In the present configuration, a burning liquid methanol droplet is suspended within an essentially one-dimensional acoustic waveguide where standing waves of variable frequency and amplitude are generated by a loud speaker placed at the end of the guide. Focus has been placed in normal gravity experiments on excitation conditions in which the droplet is situated…[more]

Rocket Propulsion: Transcritical Coaxial Jet Instabilities

Acoustically coupled combustion instabilities can result in very large scale, potentially catastrophic pressure oscillations in a range of propulsion systems, including liquid rocket engines (LREs). The present studies focus on coaxial jet flows, both non-reactive and reactive, operating in the transcritical regime, i.e., in the thermodynamic regime where no phase boundaries exist…[more]

Previous EPRL Research

Hypersonic Flight Testing: Phoenix Testbed

The Phoenix Air Launched Small Missile (ALSM) flight testbed is proposed to meet requirements for relatively inexpensive, in-flight testing in the Mach 3-6 range. The ALSM could potentially fill a gap in flight test capabilities with respect to altitude and Mach number, as indicated in Figure 1, and would clearly provide useful data under flow conditions that are more realistic than in ground-based wind tunnel facilities….[more]

Aerospace Safety: Hydrogen Leak Detection

Hydrogen is widely in use in rocket propulsion systems, and as such, leakage of hydrogen from high pressure fuel tanks requires accurate quantification. Safety concerns have led to the practice of conducting leak tests with helium (an inert gas) and to try to infer the hydrogen leak rates from helium data, often employing assumptions of essentially isentropic flow processes and choked leak orifices. The present experimental study sought to precisely quantify the relationships between hydrogen and helium leak rates for various types of leaks…[more]

Combustion Generated Air Pollutants: Lobed Fuel Injector

This project involves modeling, design, construction, and testing of a unique lobed injector/burner. The shape of the burner is designed to generate a large degree of streamwise vorticity with low a pressure drop. This results in very rapid mixing of the fuel, which is introduced through the slot, and the surrounding air. Near the injector exit strain rates can be made high enough to suppress combustion, so that burning occurs further downstream in a partially premixed mode…[more]

Hazardous waste Incineration: Resonant Dump Combustor

This project adapts high volumetric heat release rate aerospace combustion technology to hazardous waste incineration. The incinerator is derived from an aerospace dump combustor. A pre-mixed flame is stabilized within a rectangular duct by a sudden expansion in cross section at the dump plane. Waste is injected into hot, oxidative recirculation regions downstream of the dump plane, where it experiences relatively long residence times in comparison to incinerators of comparable size but of more conventional design…[more]

Aerospace Propulsion: In-flight Imaging of Transverse Jets

This experimental and theoretical study (completed) is directed towards a better understanding of the penetration and mixing of transverse jet injected into crossflows. Analytically oriented models have been developed emphasizing the the dynamics of the vortical structures observed to dominate the cross-section of transverse jets injected into a crossflow of the same phase. Model results are compared with experimental jet trajectories. Recent experimental measurements are concentrated in the transonic regime, where no previous measurements exist…[more]