Agglomeration in solid rocket propellants: novel experimental and modeling methods

Maggi, F.; Bandera, A.; Luca, L.T. De; Thoorens, V.; Trubert, Jean-François; Jackson, T. L.

doi:10.1051/eucass/201102081

Cited by 26 publications

(10 citation statements)

References 15 publications

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“…The hazardous properties of the propellant compositions to impact stimuli were determined by applying the fall hammer method (2 kg drop weight) in a Bruceton staircase apparatus [16] and results were given in terms of the statically obtained 50 % probability of explosion (H 50 ). The friction sensitivity was measured with a Julius Peter apparatus [17] by incrementally increasing the load from 0.2 to 36 kg, until no ignition was noted in five consecutive test samples.…”

Section: Hazardous Properties Testmentioning

confidence: 99%

Effects of Different Nano‐Metric Particles on the Properties of Composite Solid Propellants

Pang

Fan²,

Zhao³

et al. 2014

Propellants Explo Pyrotec

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Several industrial‐ and research‐type composite solid propellants containing different nano‐metric metal particles (such as aluminum, zirconium and titanium) with similar nominal composition, were prepared and experimentally analyzed. The effects of different nano‐metric powders on the rheological properties for metal/HTPB slurries and AP‐based composite propellant slurries were investigated. The strand burning rate and the associated combustion flame structure of propellants were determined. The energetic properties and the hazardous properties of propellants prepared were analyzed and the properties mentioned above were compared to those of a conventional aluminized propellant. The results show that aluminum powder can be sufficiently dispersed in HTPB binder. The propellant formulations containing nano‐metric particles are sensitive to impact and friction except for the base propellant with common aluminum powder, which is less sensitive to friction as compared to the other compositions. The nano‐metric additives can affect the combustion behavior and increase the burning rate of propellants compared with the common one (the reference propellant composition).

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Section: Hazardous Properties Testmentioning

confidence: 99%

Effects of Different Nano‐Metric Particles on the Properties of Composite Solid Propellants

Pang

Fan²,

Zhao³

et al. 2014

Propellants Explo Pyrotec

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“…In previous papers, the authors showed that an agglomeration process could be correlated to the pocket size through higher-order statistical descriptors [11,18,30]. The radial distribution function (RDF; also known as pair-correlation function) belongs to the family of second-order statistics.…”

Section: A Dimension Of Pocketmentioning

confidence: 99%

“…Some hundreds of agglomerates were measured after the release from the combustion surface by means of a consolidated optical technique based on high-speed camera visualizations and long-range microscopy [11]. The current experimental procedure enables measurements of items as small as 30 μm, for combustion occurring in the range of 5 to 40 bar.…”

Section: Potential Agglomeration: Experimental Considerationsmentioning

confidence: 99%

“…Babuk et al worked on the problem through collection and measurement of condensed combustion products (CCPs) generated from propellant formulations with varying oxidizer sizes [8]. In this respect, the Space Propulsion Laboratory (SPLab) research group has from Politecnico di Milano investigated this matter with both experimental and theoretical activities, as summarized in a recent paper [11].…”

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confidence: 99%

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Pocket Model for Aluminum Agglomeration Based on Propellant Microstructure

Maggi

DeLuca

Bandera³

2015

AIAA Journal

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The propellant microstructure is addressed for the interpretation and the prediction of agglomerate size distribution in aluminized composite solid rocket propellants. Although the mixing process of a propellant is intrinsically random, repetitive fuel-rich local structures (pockets) are generated in the bulk. Pockets are privileged locations for agglomerate generation. In the present work, second-order spatial statistics are applied to model propellants for the characterization of the microstructure and for the definition of an agglomeration model. The model propellants used in this work are generated by a packing code on the basis of real formulations, which are experimentally characterized for validation purposes. The average size and the metal content of the pockets are derived from the interpretation of the radial distribution function. The model is capable of predicting the size distribution of the incipient agglomerates for given propellant microstructures, using one free parameter for the tuning. The fitting of experimental agglomeration data from four different industrial propellants suggests that the free parameter can be expressed as a power function of the combustion pressure and that the microstructure agglomeration model produces particle distributions that reasonably match with the experimental data

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“…Their characteristic time was defined as t ch = 2l ch / ṙ and was found to follow the relation D 43 = 2.892 t ch 0.997 , where D 43 is the average agglomerate diameter taken from experiments, and ṙ is the propellant burning rate. In a later work, Maggi et al [24] combine a theoretical 2D and 3D numerical packing approach with careful analysis of experimental high-speed photography of propellant combustion. They show good agreement between model predictions and experimental results, and suggest a nearly-linear relation between propellant characteristic time, as defined by [23], and the ejected agglomerate diameter.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Agglomeration Phenomena in Combustion of Aluminized Composite Solid Propellant

Yavor

Gany

Beckstead

2013

Propellants Explo Pyrotec

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A theoretical model was developed in order to predict the size of agglomerates ejected from aluminized composite solid propellants. The model accounts for aspects of both mechanistic and geometric approaches. A thin mobile surface layer is assumed to dominate particle accumulation. Agglomeration number N ag expressing the ratio between ignition and accumulation times, was found to greatly affect the characteristics of agglomeration phenomena, as noted in previous works. The concept of a characteristic distance D e of the mobile surface layer was introduced, depending mostly on coarse AP particle diameter and loading. It was found to have a significant effect on the resulting agglomerate diameter. An agglomeration threshold was defined as the particle diameter equal to the mobile layer thickness. Particles smaller than this threshold have shown tendency to form large agglomerates, whereas particles with a somewhat larger diameter have demonstrated faster ignition and smaller ejected agglomerates. Model predictions for a number of propellant compositions showed good agreement with other theoretical studies as well as with experimental results.

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Agglomeration in solid rocket propellants: novel experimental and modeling methods

Cited by 26 publications

References 15 publications

Effects of Different Nano‐Metric Particles on the Properties of Composite Solid Propellants

Effects of Different Nano‐Metric Particles on the Properties of Composite Solid Propellants

Pocket Model for Aluminum Agglomeration Based on Propellant Microstructure

Modeling of the Agglomeration Phenomena in Combustion of Aluminized Composite Solid Propellant

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