LOX/GH2 Shear Coaxial Injector Atomization Studies: Effect of Recess and Non-Concentricity

Woodward, Roger; Pal, Snehanshu; Farhangi, S.; Jensen, Gregory C.; Santoro, Robert J.

doi:10.2514/6.2007-571

Cited by 24 publications

(13 citation statements)

References 16 publications

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“…This enhanced mixing provides a stronger anchoring point to the flame and might be a reason why recessed injectors are less prone to combustion instability. However, Woodward et al 33 investigated a configuration with a coflow and found little change in the dark core length and in the combustion e ciency between a recessed and a non-recessed injector. Similar investigations have also been conducted recently in a non-reacting setting, both experimentally and numerically.…”

Section: Ivc Influence Of the Recessmentioning

confidence: 97%

Large-Eddy simulation of a reactive shear coaxial injector configuration

Sánchez

Masquelet

Menon

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Acquiring experimental data on hydrogen/oxygen coaxial elements under realistic conditions (super-critical pressure, liquid oxygen, high momentum flux ratios) is di cult and the injection of hydrogen at cryogenic temperature makes it even more complex. Not only are there additional cooling requirements but the same injector that provides realistic momentum/velocity ratios with room-temperature hydrogen will produce very small momentum/velocity ratios with a cryogenic hydrogen injection at the same flow rate. The reduced fuel injection temperature has been shown to change the combustion characteristics of the chamber, a phenomenon that is not fully understood yet. Here, a single-element liquid-oxygen gaseous-hydrogen shear-coaxial injector is studied with hydrogen injected at 50 K. Performing three-dimensional simulations of these type of configurations is very costly due to the dimensions of the chamber, the range of scales and also to the diversity of physical phenomena involved, such as complex thermodynamics at elevated pressure. This work investigates the use of two-dimensional models of the real three-dimensional configuration to perform parametric studies. The main advantage of the two-dimensional simulations compared to the full chamber is the reduction in computational cost. Although the flow features observed with the 2D model are not identical to the ones found in the three-dimensional case, some common characteristics can be reproduced. This paper highlights the similarity and di↵erences between two-dimensional and three-dimensional cases and identifies which issues can be studied using two-dimensional simulations. Nomenclature D= mass di↵usivity, m 2 · s 1 DLOX = diameter of the oxygen injector e T = total energy (internal + kinetic) per unit mass, J · kg 1 H sgs = subgrid enthalpy flux, J · m 2 h k = partial mass enthalpy of species k, J · kg 1 J k = mass di↵usion flux, kg · m 2 k sgs = turbulent kinetic energy, m 2 · s 2 NS = total number of species p = pressure, P a QIK = heat flux in the Irving-Kirkwood form, J · m 2 Q sgs k = subgrid enthalpy flux due to di↵usion of species k, J · m 2 QV = volumetric heat release, J/s/m 3 R = gas constant, J · kg 1 · K 1 T = temperature, K t = time, s u = velocity, m · s 1 V k = di↵usion velocity of species k, m · s 1 xi = Cartesian coordinate, m Y k = mass fraction of species k ⌦ sgs k = subgrid di↵usive flux of species k, kg · m 2 ⇢ = density, kg · m 3 sgs = subgrid heat flux, J · m 2 ⌧ij = stress tensor ⌧res = flow residence time, ṡ ! k = reaction rate of species k ⇤ Research engineer † Professor and AIAA Associate Fellow

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Section: Ivc Influence Of the Recessmentioning

confidence: 97%

Large-Eddy simulation of a reactive shear coaxial injector configuration

Sánchez

Masquelet

Menon

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…Operating spaces of four other combustion instability research facilities are shown, including the BKH combustor of DLR, Germany, the Common Research Combustor (CRC) of CNRS, France and DLR, Germany, the Multi-Injector Combustor (MIC) of ONERA and CNRS, France, and the Cryogenic Combustion Laboratory (CCL) of Pennsylvania State University, USA. These facilities were specifically chosen for comparison because detailed flow conditions for oxygenhydrogen stability experiments for shear-coaxial jets are available in published literature 5,7,8,12,13 , but one must be cognizant that apparatuses such as these often see multiple modifications in only a few years time. As a result, Fig.…”

Section: B Fluid Supply Systemsmentioning

confidence: 99%

Development of a Facility for Combustion Stability Experiments at Supercritical Pressure

Wegener

Leyva

Forliti

et al. 2014

52nd Aerospace Sciences Meeting

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Combustion instability in liquid rocket engines can have severe consequences including degraded performance, accelerated component wear, and potentially catastrophic failure. High-frequency instabilities, which are generally the most harmful in liquid rocket engines, can be driven by interactions between disturbances associated with transverse acoustic resonances and the combustion process. The combustion response to acoustic perturbation is a critical component of the instabililty mechanism, and is in general not well understood. The current paper describes an experimental facility at the Air Force Research Laboratory (AFRL) at Edwards Air Force Base that is intended to investigate the coupling between transverse acoustic resonances and single/multiple liquid rocket engine injector flames.Critical aspects of the facility will be described, including the capability to operate at supercritical pressures that are relevant to high-performance liquid rocket engines, accurately-controlled and cryogenically-conditioned propellants, and optical access to facilitate the use of advanced diagnostics. The transverse acoustic resonance is induced through the use of carefully-controlled piezoelectric sirens, allowing monochromatic excitation across a range of amplitudes at a number of discrete frequencies. The location of the flame within the acoustic resonance mode shape can also be varied through relative phase control of the two acoustic sources. The operating space of the facility, for oxygen and hydrogen operation, will be described. Preliminary nonreacting and reacting data will also be presented to demonstrate the quality of operation of this facility. It is anticipated that future results generated using this facility will provide both fundamental insight into the acoustic-flame interactions as well as provide a database useful for validating combustion instability models. NomenclatureA = area c = speed of sound 2 D 1 = inner injector inner diameter D 2 = inner injector outer diameter D 3 = outer injector inner diameter D 4 = outer injector outer diameter dt = time step f F = acoustic frequency m = waveguide flare constant p c = mean chamber pressure pʹ = acoustic pressure perturbation amplitude t = inner post thickness uʹ = acoustic velocity perturbation amplitude x = streamwise (longitudinal) coordinate axis y = spanwise (transverse) coordinate axis z = depthwise coordinate axis

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“…However, the shear-coaxial injector has several disadvantages. These disadvantages include the high density gradient distribution at the center of a spray, limited throttling capacity, high manufacturing costs because of the concentricity on the performance, 1 and the instability phenomenon in the configuration of the recessed center post or tapered edge. 2 To improve these drawbacks, a liquid rocket engine using storable fuel, such as the RD-170, is equipped with a coaxial-swirl injector.…”

Section: Introductionmentioning

confidence: 98%

Combustion Characteristics on a Coaxial-Porous Injector

Kim

Lee

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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A coaxial-porous injector concept for gas-liquid combustion is proposed as a means of improving the mixing performace of a conventional shear-coaxial injector. The coaxialporous injector discharges a gas jet in the normal direction of the center liquid core, and it is expected that the momentum transfer from the radial gas jet to the axial liquid jet occurs more efficiently than it does with a traditional shear-coaxial injector. To validate the effectiveness of this idea, the combustion performances between the coaxial-porous injector and the shear-coaxial injector were compared by conducting a hot-firing test using nitrous oxide-ethanol combinations as propellant. The momentum flux ratio at the injector tip was selected as a spraying condition index, and the characteristic velocity efficiency was considered as a combustion performance parameter. The coaxial-porous injector demonstrated higher combustion efficiency than the conventional shear-coaxial injector, especially at the lower momentum flux ratio condition. In addition, the comparison of spray images between the shear-coaxial and coaxial porous injector supported the results of the hot-firing experiment quite well. Nomenclature AR= ratio of gas to liquid injection area at the tip A cc = combustion chamber area A G = gas injection area at the injector tip A L = liquid injection area at the injector tip A t = nozzle throat area C * = characteristic velocity J tip = momentum flux ratio at the tip of injector J tip,combustion = momentum flux ratio at the tip of injector in conditions of combustion L cc = combustion chamber length L * = characteristic length G m = mass flow rate of gas L m = mass flow rate of liqud OFR = O/F ratio P cc = chamber pressure tot m= total mass flow rates R G = gas constant of oxidizer ρ G = gas density ρ L = liquid density ρ tip = gas density at the tip of injector T G = gas temperature

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LOX/GH2 Shear Coaxial Injector Atomization Studies: Effect of Recess and Non-Concentricity

Cited by 24 publications

References 16 publications

Large-Eddy simulation of a reactive shear coaxial injector configuration

Large-Eddy simulation of a reactive shear coaxial injector configuration

Development of a Facility for Combustion Stability Experiments at Supercritical Pressure

Combustion Characteristics on a Coaxial-Porous Injector

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