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Combustion analysis of RDX propellan...

Kumbhakarna, Neeraj R.

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Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients./
Author:	Kumbhakarna, Neeraj R.
Description:	286 p.
Notes:	Source: Dissertation Abstracts International, Volume: 75-11(E), Section: B.
Contained By:	Dissertation Abstracts International75-11B(E).
Subject:	Engineering, Mechanical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3583374
ISBN:	9781321150186

Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients.
Kumbhakarna, Neeraj R.

Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients. - 286 p.

Source: Dissertation Abstracts International, Volume: 75-11(E), Section: B.

Thesis (Ph.D.)--The Pennsylvania State University, 2014.

The present research is conducted with an objective to enhance the understanding of combustion process of the widely used cyclotrimethylene trinitramine (RDX) propellant and also that of novel high-nitrogen energetic materials. These high-nitrogen materials are potential propellant additives for performance improvement. The research is presented in three parts. In the first part a detailed model of steady-state combustion of a pseudo-propellant containing RDX and triaminoguanidinium azotetrazolate (TAGzT) is presented. The physicochemical processes occurring within the foam layer, comprised of liquid and gas bubbles, and a gas-phase region above the burning surface are considered. The chemical kinetics is represented by a global thermal decomposition mechanism within the liquid by considering 18 species and 8 chemical reactions. The reactions governing decomposition of TAGzT were deduced from separate confined rapid thermolysis experiments using Fourier transform infrared (FTIR) spectroscopy and time-of-flight mass spectrometry (ToFMS). Within the gas bubbles and gas-phase region, a detailed chemical kinetics mechanism was used by considering up to 93 species and 504 reactions. The pseudo propellant burn rate was found to be highly sensitive to the global decomposition reactions of TAGzT. The predicted results of burn rate agree well with experimental burn-rate data. The increase in burn rate by inclusion of TAGzT is due in part from exothermic decomposition of the azotetrazolate within the foam layer, and from fast gas-phase reactions between triaminoguanidine decomposition products, such as hydrazine, and oxidizer products from the nitramine decomposition. To improve the predictive capability of combustion models like the one discussed above, it is essential to understand the liquid-phase decomposition chemistry of propellants and their additives. Hence in the second part of this research, the decomposition of liquid-phase RDX was studied using FTIR spectroscopy of evolved gas-phase species from rapid thermolysis and of the condensate and residue formed from the decomposition. Sub-milligram sample of RDX was heated at rates of about 2000 K/s to a set temperature where decomposition occurred under isothermal conditions. Since RDX melts at around 205°C, decomposition studies were conducted at temperatures ranging from 265 to 305°C. 1,3,4- oxadiazole (C2N2H2O, m/z=70) was one of the compounds detected in the thermolysis tests. A chemical reaction mechanism explaining the formation of 1,3,4-oxadiazole is postulated based on the acquired experimental data, thermochemical analysis and related studies. The "cage effect" principle that is important when reactions take place in a liquid phase is applied. Finally in the third part of this research, a detailed reaction mechanism of the decomposition of the highnitrogen compound guanidinium 5-amino tetrazolate (GA) in the liquid phase is formulated. This compound is chosen because it has a simpler molecular structure as compared to TAGzT. A combined experimental and computational approach is used. The experimental information comes from data published in the literature. The computational approach is based on using quantum mechanics for identifying species and determining the kinetic rates, resulting in 55 species and 85 elementary reactions. In these ab initio techniques, various levels of theory and basis sets were used. A continuum-based model for predicting species formation and mass loss of a thermogravimetric analysis (TGA) experiment was also developed and solved numerically, accounting for reversible chemical reactions and mass transfer in the computational simulations of the GA decomposition process. The model accounts for reactions within the liquid phase and evaporation of several of the observed experimentally measured products. Simulation results for species concentrations and heat release were obtained, and these results were found to satisfactorily match the temporal experimental results previously published in literature for the decomposition of GA. Important reaction pathways in the proposed reaction scheme were identified based on a sensitivity analysis.

ISBN: 9781321150186Subjects--Topical Terms:

783786
Engineering, Mechanical.

Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients.
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020 $a 9781321150186
035 $a (MiAaPQ)AAI3583374
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100 1 $a Kumbhakarna, Neeraj R. $3 3168929
245 1 0 $a Combustion analysis of RDX propellant and novel high-nitrogen propellant ingredients.
300 $a 286 p.
500 $a Source: Dissertation Abstracts International, Volume: 75-11(E), Section: B.
500 $a Adviser: Stefan T. Thynell.
502 $a Thesis (Ph.D.)--The Pennsylvania State University, 2014.
520 $a The present research is conducted with an objective to enhance the understanding of combustion process of the widely used cyclotrimethylene trinitramine (RDX) propellant and also that of novel high-nitrogen energetic materials. These high-nitrogen materials are potential propellant additives for performance improvement. The research is presented in three parts. In the first part a detailed model of steady-state combustion of a pseudo-propellant containing RDX and triaminoguanidinium azotetrazolate (TAGzT) is presented. The physicochemical processes occurring within the foam layer, comprised of liquid and gas bubbles, and a gas-phase region above the burning surface are considered. The chemical kinetics is represented by a global thermal decomposition mechanism within the liquid by considering 18 species and 8 chemical reactions. The reactions governing decomposition of TAGzT were deduced from separate confined rapid thermolysis experiments using Fourier transform infrared (FTIR) spectroscopy and time-of-flight mass spectrometry (ToFMS). Within the gas bubbles and gas-phase region, a detailed chemical kinetics mechanism was used by considering up to 93 species and 504 reactions. The pseudo propellant burn rate was found to be highly sensitive to the global decomposition reactions of TAGzT. The predicted results of burn rate agree well with experimental burn-rate data. The increase in burn rate by inclusion of TAGzT is due in part from exothermic decomposition of the azotetrazolate within the foam layer, and from fast gas-phase reactions between triaminoguanidine decomposition products, such as hydrazine, and oxidizer products from the nitramine decomposition. To improve the predictive capability of combustion models like the one discussed above, it is essential to understand the liquid-phase decomposition chemistry of propellants and their additives. Hence in the second part of this research, the decomposition of liquid-phase RDX was studied using FTIR spectroscopy of evolved gas-phase species from rapid thermolysis and of the condensate and residue formed from the decomposition. Sub-milligram sample of RDX was heated at rates of about 2000 K/s to a set temperature where decomposition occurred under isothermal conditions. Since RDX melts at around 205°C, decomposition studies were conducted at temperatures ranging from 265 to 305°C. 1,3,4- oxadiazole (C2N2H2O, m/z=70) was one of the compounds detected in the thermolysis tests. A chemical reaction mechanism explaining the formation of 1,3,4-oxadiazole is postulated based on the acquired experimental data, thermochemical analysis and related studies. The "cage effect" principle that is important when reactions take place in a liquid phase is applied. Finally in the third part of this research, a detailed reaction mechanism of the decomposition of the highnitrogen compound guanidinium 5-amino tetrazolate (GA) in the liquid phase is formulated. This compound is chosen because it has a simpler molecular structure as compared to TAGzT. A combined experimental and computational approach is used. The experimental information comes from data published in the literature. The computational approach is based on using quantum mechanics for identifying species and determining the kinetic rates, resulting in 55 species and 85 elementary reactions. In these ab initio techniques, various levels of theory and basis sets were used. A continuum-based model for predicting species formation and mass loss of a thermogravimetric analysis (TGA) experiment was also developed and solved numerically, accounting for reversible chemical reactions and mass transfer in the computational simulations of the GA decomposition process. The model accounts for reactions within the liquid phase and evaporation of several of the observed experimentally measured products. Simulation results for species concentrations and heat release were obtained, and these results were found to satisfactorily match the temporal experimental results previously published in literature for the decomposition of GA. Important reaction pathways in the proposed reaction scheme were identified based on a sensitivity analysis.
590 $a School code: 0176.
650 4 $a Engineering, Mechanical. $3 783786
650 4 $a Chemistry, Molecular. $3 1676084
650 4 $a Chemistry, General. $3 1021807
690 $a 0548
690 $a 0431
690 $a 0485
710 2 $a The Pennsylvania State University. $b Mechanical Engineering. $3 2103981
773 0 $t Dissertation Abstracts International $g 75-11B(E).
790 $a 0176
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3583374