Problems in studying formation of smoke oxide particles in combustion of aluminized solid propellants

Self Cite

The present work is devoted development of model of agglomerating process for propellants based on ammonium perchlorate (AP), ammonium dinitramide (ADN), HMX, inactive binder, and nanoaluminum. Generalization of experimental data, development of physical picture of agglomeration for listed propellants, development and analysis of mathematical models are carried out. Synthesis of models of various phenomena taking place at agglomeration implementation allows predicting of size and quantity, chemical composition, structure of forming agglomerates and its fraction in set of condensed combustion products. It became possible in many respects due to development of new model of agglomerating particle evolution on the surface of burning propellant. Obtained results correspond to available experimental data. It is supposed that analogical method based on analysis of mathematical models of particular phenomena and their synthesis will allow implementing of the agglomerating process modeling for other types of metalized solid propellants.

Section: Ignition and Burning Of Metalmentioning

confidence: 99%

Analysis and synthesis of solutions for the agglomeration process modeling

Babuk

Dolotkazin

Nizyaev

2013

Self Cite

“…Leaving the burning surface, combustion of agglomerates progresses in the core §ow of the rocket. Submicrometric CCP, referred to as smoke oxide particles (SOP), mainly come from the combustion of aluminum particles and agglomerates sustained by species di¨usion around the metal drop [4]. Incomplete combustion of metal agglomerates may be promoted by a limited residence time in the combustion chamber, a small characteristic length L * , low burning rate, or low combustion temperature, thus loosing the corresponding fraction of combustion enthalpy.…”

Section: Agglomerationmentioning

confidence: 99%

“…The ¦nal size of the agglomerates is strongly in §uenced by the residence time of the metal powders on the surface. In case of propellants containing micrometric aluminum powders, fast-and slowburning conditions should generate di¨erent scenarios as described in [3,4,6]. In the former conditions, the reduced residence time results in the so-called subpocket agglomeration that generates more agglomerates from one original pocket.…”

Section: Agglomerationmentioning

confidence: 99%

See 1 more Smart Citation

Agglomeration in solid rocket propellants: novel experimental and modeling methods

Maggi

Bandera

Luca

et al. 2011

Metal agglomeration is a key factor a¨ecting the performance of metalized solid propellant rockets since many of the mechanisms that degrade speci¦c impulse can be ascribed to metal powder aggregation and agglomeration. Condensed combustion products are generated at or near the burning surface of the propellant and then released in the gas phase where they are shaped by the core §ow viscous forces and oxidized by the reactive environment. On this basis, detailed information about the size of agglomerates as they are generated from the propellant may improve the knowledge of the core §ow and, thus, the prediction of its e¨ects (namely, two-phase §ow losses). This topic entails both modeling and experimental activities, and the aim of this work is to present some recent developments achieved at the Space Propulsion Laboratory in cooperation with other international institutions. The experimental part shows the application of high-speed and high-resolution imaging of propellant combustion for automated measurement of particle size exploited by means of an ad-hoc image processing tool. The modeling part demonstrates how heterogeneity can explain the agglomeration by means of a pocket model using spatial statistics and two-(2D) or threedimensional (3D) virtual propellants. A de¦nition of a characteristic time that ¦ts the agglomeration data for tested propellants is suggested, and a method for predicting the agglomerate size is given. Both activities are still a matter of research but the maturity level reached so far permits the application in some practical cases. Progress in Propulsion Physics2 (2011) 81-98

“…Thus, this process is a source of SOPs at burning of the propellants of the considered type. The size of formed oxide particles depends on the time of their stay in the ¤trail¥ of burning particles where condensation and coagulation phenomena take place [18]. This size increases with the time of stay and vice versa: reduction of the size of the agglomerating particles results in the reduction of this time.…”

Section: A An-based Propellantsmentioning

confidence: 99%

Condensed combustion products from burning of nanoaluminum-based propellants: properties and formation mechanism

Babuk¹,

Glebov²,

Dolotkazin³

et al. 2009

The experimental results obtained within a joint international research e¨ort regarding the formation of condensed combustion products from nanoaluminum-based solid propellants (SPs) are reported. Data on the size, structure, chemical composition, and quantity of condensed combustion products (CCPs) as well as conditions of their formation are discussed. On the basis of the collected experimental data, a general physical picture of condensed combustion products formation is portrayed. The results of this study allow carrying out the analysis of good quality propellants using nanoaluminum.