Two-phase flows in the nozzles of solid rocket motors

Васенин, И. М.; Narimanov, R. K.; Glazunov, A. A.; Kuvshinov, Nikita; Иванов, В. А.

doi:10.2514/3.23884

Cited by 9 publications

(5 citation statements)

References 7 publications

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“…Despite their significantly increased reactivity compared to conventional thermites, the applications for nanothermites remain limited. They form primarily condensed combustion products, leading to two phase losses undesirable for many propulsion and explosive systems . In addition, nanothermites were reported to be highly sensitive to ignition by electrostatic discharge (ESD) making them difficult to handle.…”

Section: Introductionmentioning

confidence: 99%

Combustion of Aluminum‐Metal Fluoride Reactive Composites in Different Environments

Valluri

Schoenitz

Dreizin

2019

Propellants Explo Pyrotec

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Combustion of two nanocomposite powders comprising equal mass fractions of aluminum and a metal fluoride, BiF3 or CoF2, is characterized experimentally. The powders were prepared by arrested reactive milling; earlier work showed that they are readily ignited upon heating and are insensitive to ignition by electrostatic discharge. Here, powder particles were ignited in air by passing through a focused CO2 laser beam. They were also ignited and burned in oxygen‐starved environments produced in the combustion products of an air‐acetylene and air‐hydrogen flames. Burn times and color temperatures of the particles were measured optically. Combustion products were collected and examined using electron microscopy. Correlations of burn times with particle sizes showed that the composites containing BiF3 burned faster than those containing CoF2. In air, the burn rates of both composite powders exceeded that of pure Al; in the oxygen‐starved environments the burn rates of the prepared composites were comparable to that of Al. The flame temperatures of the CoF2‐containing composite were limited by the Al boiling point while BiF3 containing composites burned at higher temperatures. Combustion mechanisms for the prepared materials are discussed qualitatively.

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Section: Introductionmentioning

confidence: 99%

Combustion of Aluminum‐Metal Fluoride Reactive Composites in Different Environments

Valluri

Schoenitz

Dreizin

2019

Propellants Explo Pyrotec

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“…Through energy conservation arguments, the Green's function for the heat transfer rate to a rotating particle can be expressed as 2 …”

Section: Analysis Of Rotation Effectsmentioning

confidence: 99%

“…Alumina droplets commonly account for 20% to 40% of the total mass flow through the nozzle entrance, so the high number density and considerable relative velocities between droplets of different sizes allow for a large number of collisions. Most of these collisions result in coalescence of the droplets into larger agglomerates, which rotate according to the dynamics of off-center coalescing collisions [2]. At the same time, larger droplets tend to break apart within the nozzle due to collisions or surface stresses imposed by the accelerating gas, and these breakup processes may impose significant angular momentum on the resulting droplet products.…”

Section: Introductionmentioning

confidence: 99%

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Particle Rotation Effects in Rarefied Two-Phase Plume Flows

Burt

Boyd²

2005

AIP Conference Proceedings

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Abstract. We evaluate the effects of solid particle rotation in high-altitude solid rocket exhaust plume flows, through the development and application of methods for the simulation of two phase flows involving small rotating particles and a nonequilibrium gas. Green's functions are derived for the force, moment, and heat transfer rate to a rotating solid sphere within a locally free-molecular gas, and integration over a Maxwellian gas velocity distribution is used to determine the influence of particle rotation on the heat transfer rate at the equilibrium limit. The use of these Green's functions for the determination of particle phase properties through the Direct Simulation Monte Carlo method is discussed, and a procedure is outlined for the stochastic modeling of interphase collisions. As a test case, we consider the nearfield plume flow for a Star-27 solid rocket motor exhausting into a vacuum, and vary particle angular velocities at the nozzle exit plane in order to evaluate the influence of particle rotation on various flow properties. Simulation results show that rotation may lead to slightly higher particle temperatures near the central axis, but for the case considered the effects of particle rotation are generally found to be negligible.

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“…A total correlation of size and velocities is assumed at the semi-kinetic level and correlations are enforced at the multi-fluid level with a (usually constant) velocity closure in each section, which yet introduces little error if inertia and polydispersity are not too strong, these aspects being discussed in the present paper. Integrating on a continuous size variable in each section is a key aspect: while most Eulerian approaches, based on size sampling, consider discrete droplet sizes gathered into ''classes'' which cannot account for the new droplet sizes created by coalescence (except scarce examples [60]), continuous size approaches such as the multi-fluid method hereafter described are the only Eulerian methods handling coalescence naturally and rigorously. Some Eulerian approaches based on quadratures of the whole size support can capture the trend of the size distribution evolution due to coalescence [29] but matters of size velocity correlations are not all solved yet.…”

Section: Introductionmentioning

confidence: 99%

Eulerian multi-fluid models for the simulation of dynamics and coalescence of particles in solid propellant combustion

Doisneau

Laurent

Murrone

et al. 2013

Journal of Computational Physics

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Keywords:Polydisperse spray High order Eulerian multi-fluid model Adaptive quadrature for coalescence integrals Solid propellant combustion Aluminum oxide droplets CEDRE code a b s t r a c tThe accurate simulation of polydisperse sprays undergoing coalescence in unsteady gaseous flows is a crucial issue. In solid rocket motors, the internal flow depends strongly on the alumina droplet size distribution, which spreads up with coalescence. Yet solving for unsteady two-phase flows with high accuracy on the droplet sizes is a challenge for both modeling and scientific computing. As an alternative to Lagrangian approaches, a wide range of Eulerian models have been recently developed to describe the disperse liquid phase at a lower cost, with an easier coupling to the gaseous phase and with massively parallel codes. Among these models, the multi-fluid model allows the detailed description of polydispersity and size/velocity correlations by separately solving fluids of size-sorted droplets, the so-called sections. The existing one size moment method, which describes the size distribution with one size moment per section, provides simple and fast resolution for coalescence. On the other hand, a two size moment method has been suggested to reduce the number of sections but it lacks an efficient coalescence resolution method. After introducing a new strategy for two size moment coalescence, the two methods are compared on various configurations in a research code and an industrial-oriented code, in order to conclude on computational accuracy and cost. Then the paper aims at describing the most efficient approach for multi-dimensional unsteady and eventually coalescing rocket chamber simulations. Its objective is threefold: first, to validate the two size moment method by comparing simulations to reference solutions and dedicated experimental measurements conducted at ONERA, second to study the efficiency and robustness of both methods, third, to draw some firm conclusions about the necessity to use the one size moment or two size moment method to simulate solid propellant alumina sprays. We finally perform the first simulations of coalescence in realistic 2D boosters with the two size moment method, implemented in the industrial-oriented code CEDRE.

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Two-phase flows in the nozzles of solid rocket motors

Cited by 9 publications

References 7 publications

Combustion of Aluminum‐Metal Fluoride Reactive Composites in Different Environments

Combustion of Aluminum‐Metal Fluoride Reactive Composites in Different Environments

Particle Rotation Effects in Rarefied Two-Phase Plume Flows

Eulerian multi-fluid models for the simulation of dynamics and coalescence of particles in solid propellant combustion

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