The Hypersonic International Flight Research Experimentation (HIFiRE) program is a collaborative international effort designed to study basic hypersonic phenomena through flight experimentation. On 1 May 2012, the HIFiRE Flight 2 project successfully flew ...

Air-breathing hypersonic vehicles are based on an airframe-integrated scramjet engine. The elongated forebody that serves as the inlet of the engine is subject to harsh aerothermodynamic loading, which causes it to deform. Unpredicted deformations may ...

Combustion mode transitions triggered through active fuel actuation and passive wall heating have been examined in a direct-connect dual-mode combustor experiment. Nonallowable flow configurations are identified through the comparison of the experimental ...

The analysis presented in Part I of this study is extended to investigate ignition transients and flame development in an ethylene-fueled scramjet engine. Unheated gaseous ethylene is transversely injected into the combustor upstream of a recessed cavity ...

The ignition and combustion characteristics of the hydrogen plume issued from two pylon-type injectors in a Mach 2.4, high-enthalpy airflow are presented. Specifically, the focus of the study is on the effects of the imposed interaction and subsequent ...

The physical process of mode transition, in which an accelerating hypersonic propulsion ramjet progresses from dual to scramjet mode operation, is explored in the context of the HIFiRE-2 ground and flight test campaign using three-dimensional, unsteady ...

A numerical method is presented for measuring angle of attack and Mach number in the inlet of a supersonic combustor using a sensor design based on tunable diode laser absorption spectroscopy. A nonlinear least-squares fitting routine was applied to ...

The performance of hypersonic inlets is significantly affected by the presence of shock/boundary-layer interactions. To examine the potential of microramps for shock/boundary-layer interaction control in a finite-width duct, a detailed experimental and ...

The fundamental flow physics of the interaction between an array of fuel jets and a hypersonic boundary layer is investigated. Hydrogen is injected at jet-to-freestream dynamic pressure ratios ranging from 0.350 to 0.875 on a flat plate into a Mach 4.5 ...

This paper presents the mixing enhancements of a spatially developing Mc=0.3 planar mixing layer interacting with an oblique shock wave by means of large-eddy simulation. The large-scale coherent vortices are found to be modulated by the oblique shock, which ...

The performance of different boundary-layer bleed systems of a two-dimensional ramjet inlet has been investigated experimentally. The main objective of the study has been to identify the correlation between the inlet’s performance with different boundary-...

The focus of this paper is on the numerical simulation of compressible flow in diffusing S-ducts; this flow is characterized by secondary flow as well as regions of boundary-layer separation. The S-duct geometry produces streamline curvature and an ...

This paper describes the numerical investigation of convergent conical nozzles done in the AIAA Propulsion Aerodynamic Workshop number one. Axisymmetric, three-dimensional, and unsteady computations were conducted for three main test cases. These test ...

Spike surface flowfields and base wake behaviors of clustered linear aerospike nozzles under the presence of external flow were characterized using surface pressure measurements, flow visualizations using the background-oriented schlieren method, and ...

This paper presents the results of a combined experimental, numerical, and analytical study of the occurrence of different vortex breakdown types and helical instabilities in realistic swirling combustor flows with axial air injection through a ...

Unsteady numerical simulations of pintle nozzles were implemented to investigate dynamic characteristics of various pintle configurations. To take into account the effects of the pintle shape and movement, a sliding mesh method was applied. The physical ...

In ultra-compact combustors, the length of the system is reduced by integrating the turbine turning vanes within the combustor and the primary zone is in a cavity recessed from the core flow. To understand the combustion characteristics of an ultra-...

It is necessary to understand how film cooling both reduces the adiabatic wall temperature and influences the heat transfer coefficient in order to predict its benefit to a gas turbine hot gas path component. Although a great number of studies have ...

A semi-empirical one-dimensional model is developed for the incompressible lobed mixer–ejector design and optimization analysis. This model is deduced on the conservation relations of mass, momentum, and energy by using the control volume method with ...

A feasible method was developed for cooling of the extreme aerodynamic heating of strut injectors in a scramjet engine. A porous strut injector using transpiration cooling was demonstrated to be effective in a 60 s wind-tunnel test. The Mach number in the ...

A linear stability analysis has been carried out to reveal the atomization mechanism of a power-law planar liquid sheet. The dispersion equation that governs the symmetric instability of a power-law liquid sheet is obtained by considering the gas boundary-...

An acoustically consistent, linear modal analysis-based analytical method is presented to predict the longitudinal and transverse combustion instabilities in a two-dimensional Cartesian dump combustor. At first, rigorous acoustical analysis (without ...

The aim of this work is to study the role of the liquid phase in the thermoacoustic coupling, which subsequently leads to combustion instabilities. Experimental investigations were performed on an actual multipoint spray injector geometry used in real ...

The avoidance of acoustic instabilities, which may cause catastrophic failure, is demanded for liquid-propellant rocket engines. This occurs when the energy released by combustion amplifies acoustic disturbances; it is therefore essential to avoid such ...

With the increase in computational resources, time-accurate reacting flow, computational fluid dynamics have improved to the point where periodic, unsteady behavior associated with hydrodynamic instability and acoustic resonance can be accurately modeled. ...

Large solid rocket motors are subjected to pressure oscillations for which the origin lies in the coupling between hydrodynamic instabilities and the first longitudinal acoustic modes of the combustion chamber. Static firing tests using two propellant ...

In this paper, CFX is used to simulate different hybrid rocket configurations applying liquid N2O as the oxidizer and paraffin wax as the fuel. This work is intended as the prosecution of a previous study about hybrid rockets with diaphragms of different ...

A boron-based catalytic and energetic fuel additive is explored as a mechanism to enhance performance of hybrid motors using nitric-acid-based oxidizers. Ethylenediamine bisborane is highly hypergolic with nitric acid, thereby eliminating the need for a ...

A composition consisting of 80% polytetrafluoroethylene and 20% boron (by weight) was considered as a potential high-density solid fuel mixture for mixed hybrid rocket propulsive applications. Constant-pressure strand burner experiments for the given ...

The ignition and combustion properties of fuel-rich mixtures of boron and polytetrafluorethylene in air and argon were studied as a function of pressure at a heating rate of approximately 1×105  K/s to simulate heating rates that individual ingredients may be ...

The incorporation of nanoaluminum in an 86% solid composite propellant formulation poses processing problems when following conventional methods. Therefore, to accommodate an optimum percentage of nanoaluminum in such formulations, a new bicurative system ...

The combustion behaviors of gel fuels containing micro- and nanosized aluminum particles were investigated in a pressurized chamber under typical ramjet conditions. Condensed combustion products were sampled in the jet plume behind the exit nozzles with ...

A droplet stream combustion experiment was developed to understand the effect of reducing droplet size to a micrometer scale on the combustion characteristics of nanofluid fuels, which are liquid fuels with a stable suspension of nanoparticles. Pure ...

A numerical investigation of the head-on collision of two equal-sized alumina droplets has been conducted. Direct numerical simulations were performed by employing a volume of fluid method for tracking the interface and an adaptive mesh for improving the ...

Propellant management devices located within the propellant tanks of spacecraft and satellites operating in microgravity environment are used to control propellant distribution within the tank to improve vehicle dynamics and performance. In the ...

This paper presents an evaluation of the multiple-frequency phase-lagged approach, which enables the performance of unsteady Reynolds-averaged Navier–Stokes simulations on multistage turbomachinery configurations using a time-marching method. The major ...

This paper revisits an old problem of validating computational fluid dynamics simulations with experiments in turbomachinery. The case considered here is NASA rotor 37. Prior computational fluid dynamics studies of this blade have been unable to predict a ...

This paper reports the development of a new propeller design and analysis tool. JBLADE uses an improved version of blade element momentum that embeds a new model for the three-dimensional flow equilibrium. In addition, a new method for the prediction of ...