A5020738637- Combustion and flame dynamics
- Rocket and propulsion systems research
- Advanced Combustion Engine Technologies
- Computational Fluid Dynamics and Aerodynamics
- Energetic Materials and Combustion
- Heat transfer and supercritical fluids
- Combustion and Detonation Processes
- Fluid Dynamics and Turbulent Flows
- Laser-Plasma Interactions and Diagnostics
- Fire dynamics and safety research
- Wind and Air Flow Studies
- Electromagnetic Launch and Propulsion Technology
- Fluid Dynamics and Heat Transfer
- Particle physics theoretical and experimental studies
- Spacecraft and Cryogenic Technologies
- Particle Detector Development and Performance
- Aerodynamics and Acoustics in Jet Flows
- Gas Dynamics and Kinetic Theory
- High-Velocity Impact and Material Behavior
- Pulsed Power Technology Applications
- Nuclear Engineering Thermal-Hydraulics
- Electrohydrodynamics and Fluid Dynamics
- Hydrology and Sediment Transport Processes
- Model Reduction and Neural Networks
- Aeolian processes and effects
Purdue University West Lafayette
2013-2024
University of South Carolina
2023
Indian Institute of Technology Madras
2022
Humboldt-Universität zu Berlin
2022
Cochin University of Science and Technology
2022
Potsdam Institute for Climate Impact Research
2022
American Institute of Aeronautics and Astronautics
2016-2020
Montclair State University
2019
University of Tennessee at Knoxville
2018
Planar Energy (United States)
2017
The unsteady gas dynamic field in a closed combustor is determined by the nonlinear interactions between chamber acoustics, hydrodynamics, and turbulent combustion that can energize these modes. These are studied detail using hybrid RANS/large eddy simulations (RANS = Reynolds Averaged Navier-Stokes) of non-premixed, high-pressure laboratory produces self-excited longitudinal instabilities. main variable study relative acoustic length tube injects oxidizer into combustor. Assuming half-wave...
An experimental study of spontaneous longitudinal high-frequency combustion instabilities in a high-pressure model rocket combustor is described. The experiment designed to efficiently obtain stability data under variable resonance conditions single test. A traversing choked axial oxidizer inlet used vary the coupled resonances between variable-length tube and fixed-length chamber, thereby changing temporal spatial relationship fluid mechanical local pressure oscillations at head end...
The atomization characteristics of sheets formed by both laminar and turbulent impinging jets were experimentally studied as a function flow injector geometric parameters. In particular, sheet breakup length along the centerline, distance between adjacent waves apparent on sheet, drop-size distributions measured over Weber number range 350-6600 Reynolds 2.8 x 103 to 2.6 10 4. A linear stability-based model was used determine most unstable wave corresponding growth rate factor two-dimension...
Three-dimensional simulations of combustion instability can provide extremely valuable insight into the problem physics, but they represent an enormous investment in time and, thus, may preclude parametric studies that are practical with two-dimensional simulations. Three numerical unstable laboratory rocket combustor were performed to assess effect grid resolution and dimensionality on ability predict model instability. Computations show axisymmetric using both coarse fine grids able...
The study examines chemiluminescence measurements and computations as a method of validation. Because chemiluminescent radicals are present in small concentrations associated timescales also small, common assumption is that these quasi-steady-state species their transport can be ignored. This paper the above using available data simulation results, specifically aiming at single element rocket combustor under strong pressure fluctuations. Variations kinetics rate constants considered for...
Proper orthogonal decomposition and dynamic mode are evaluated for the study of self-excited longitudinal combustion instabilities in laboratory-scaled single-element gas turbine rocket combustors. Since each proper comprises multiple frequencies, specific modes pressure heat release not related, which makes analysis more qualitative less efficient identifying physical mechanisms. On other hand, generates a global frequency spectrum corresponds to discrete so that different dynamics can be...
A single injector element liquid rocket combustion experiment was designed and conducted to investigate the dynamics of a gas-centered, liquid-swirled coaxial element. The oxidizer mixture superheated water oxygen, kerosene used as fuel. mean chamber pressure ranged from 2.14 2.38 MPa. length discretely varied between 25.4 88.9 cm determine dependence stability characteristics on resonant frequency mode shape. Strong spontaneous instabilities were measured with peak-to-peak amplitudes 0.69...
An impedance bridge for high-voltage capacitance and related measurements to an accuracy of 1 ppm is described the background research development which made it possible documented. The transformer-ratioarm type, principal components are a comparator several two-stage transformers. can be used measure ratios over range from 1/1 107/1 with resolution between 0.1 0.25 ppm. highest accuracies obtained at power frequencies 50-60 Hz, but usable up 400 Hz. factors limited previously developed...
Liquid rockets are prone to large amplitude oscillations, commonly referred as thermoacoustic instability. This phenomenon causes unavoidable developmental setbacks and poses a stern challenge accomplish the mission objectives. Thermoacoustic instability arises due nonlinear interaction between acoustic reactive flow subsystems in combustion chamber. In this paper, we adopt tools from dynamical systems complex theory understand transitions state of stable operation self-excited model...
Using rocket-grade hydrogen peroxide and a nontoxic, hypergolic miscible fuel, 150-lbf thrust class pintle injector engine has been developed tested with the aim of characterizing performance under variety design operating conditions. Rapid, reproducible ignition was sustained wide range conditions using new propellant combination. Parametric studies were undertaken to assess influence characteristic chamber length L*, diameter-to-pintle diameter ratio, total momentum secondary-to-primary...
A computational fluid dynamics analysis of acoustic modes and instabilities in an experimental longitudinal test chamber is presented. The configuration a uni-element recessed injector post combined with variable-length combustion chamber. computations employ the nonlinear Euler equations mass heat addition response functions to represent dynamics. Analytical solutions comparisons are used verify validate model. results demonstrate importance including full for predicting frequencies mode...
A transverse combustion instability study composed of experimental and hybrid Reynolds-averaged Navier–Stokes/large eddy simulation results is described. The focused on gas-centered swirl coaxial injector elements like those used in the main chambers oxidizer-rich staged-combustion engines. Experimental are obtained from a self-excited, multi-element, high-pressure model rocket combustor. uses velocity forcing technique to match frequency amplitude pressure oscillations that measured...
Abstract The coupling of the physical and chemical processes controlling ignition delays (τ ign ) hypergolic propellants complicates direct analysis transient processes. transport properties both ambient gas, heat vaporization reaction affect τ must be considered experimentally. Furthermore, since occurs, by definition, on contact, mechanics initial contact subsequent mixing can also considered. Experimental results from a study catalytically promoted fuel with rocket grade hydrogen peroxide...
An experimental investigation of high-frequency longitudinal combustion instability using a continuously variable resonance combustor (CVRC) is described. The condition provided by varying the length tube carrying oxidizer into with rearward-facing step. coustic varied between quarter- and half-wave resonator. data are analyzed compared analytical results calculated linearized Eule r equations. As changes system transitions stable highly unstable operation, allowing observation several...
The development of a Linearized Euler Equation (LEE) model for analyzing high frequency longitudinal combustion instability is described. includes mean flow effects and generalized multiple domains as well natural boundary conditions that deviate from acoustically perfect conditions. These are systematically evaluated. Calculated spatial mode shapes resonant frequencies compared to experimental measurements good agreements obtained. Demonstrative results using prescribed unsteady heat...
The reflectivity of $n$-type InSb has been measured in the far infrared. doping samples was such that free-carrier plasma frequency near LO mode frequency. results suggest with a sufficiently thick damage layer show effects due to surface plasmons. Use simple model indicates surface-plasma excitations are coupled phonons.
Abstract : Combustion instability in an unstable single element rocket chamber using methane as the fuel is computationally studied. Effects of kinetics mechanism are examined by comparing results a step global and detailed with 32 species 177 reactions. Significant differences between two predictions identified including amplitude unsteady pressure oscillations, more importantly, underlying mechanisms responsible for driving combustion instabilities.