scholarly journals Experimental Study of Pyrolysis and Laser Ignition of Low-Vulnerability Propellants Based on RDX

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2276 ◽  
Author(s):  
Jordan Ehrhardt ◽  
Léo Courty ◽  
Philippe Gillard ◽  
Barbara Baschung
Keyword(s):  
Experimental Data ◽  
Mass Spectrometer ◽  
Combustion Process ◽  
Laser Ignition ◽  
Closed Volume ◽  
New Materials ◽  
Gas Chromatograph ◽  
Interior Ballistics ◽  
Ignition And Combustion ◽  
Gun Propellants

Low-vulnerability propellants are propellants designed to resist unintended stimuli to increase safety during transport, storage and handling. The substitution of usual nitrocellulose-based gun propellants with these new materials allows maintaining interior ballistics performances while increasing the safety. In this paper, the pyrolysis, ignition and combustion of such propellants are investigated in order to study conditions leading to a safe and reproducible ignition. Low-vulnerability propellants studied are made of different ratios of hexogen (RDX) and nitrocellulose (NC). Three compositions are studied by varying weight percentages of RDX and NC: 95-5, 90-10 and 85-15 for respective weight percentages of RDX-NC. Pyrolysis of these propellants is studied with two different experimental setups: a flash pyrolysis device linked to a gas chromatograph coupled to a mass spectrometer (Py-GC-MS) and a closed-volume reactor coupled to a mass spectrometer. Different molecules, like NO2, CO, CH3COCH3 or CH2NCH2NCH2, are obtained during the decomposition of these propellants. Laser ignition of these propellants is studied in a cylindrical closed-volume reactor using a laser diode. Several combustion characteristics, such as ignition delays, maximal overpressures and combustion rates are given for the three propellants using the pressure signals. Moreover, ignition energies are also investigated. Obtained results are compared to the few available literature data. A particular behavior is noticed for the 90-10 propellant. The experimental data collected should serve in the future to have a better understanding of the chemical reactions driving the combustion process of these low-vulnerability propellants.

The Main Regularities of Ignition and Combustion of Coal-Water Fuels Produced from Fat, Non-Baking Coal and Anthracite

2018 ◽  
Vol 38 ◽  
pp. 67-78 ◽  
Author(s):  
Valeriya Pinchuk
Keyword(s):  
Experimental Data ◽  
Data Processing ◽  
Experimental Research ◽  
Combustion Process ◽  
Medium Temperature ◽  
Experimental Data Processing ◽  
Ignition And Combustion ◽  
Temperature Correlations

For the purpose of defining the regularities of CWF combustion in the air, we have conducted experimental research into ignition and combustion of the fuels produced from coal of different metamorphic ranks. The studies allowed to obtain time-temperature correlations describing CWF ignition and combustion, to determine the stages of the combustion process, to define the structure of the ash coating, and the degree of the fuel combustible mass burnout. The present paper analyses the results of experimental research into the regularities underlying the processes of ignition and combustion for CWF (fat coal), CWF (non-baking coal), and CWF (anthracite).It was established that the oven medium temperature affects the duration of every CWF combustion stage, which was substantiated by the relevant dependencies resulting from the experimental data processing.

scholarly journals A Monte Carlo approach for determining cluster evaporation rates from concentration measurements

2016 ◽  
Author(s):  
Oona Kupiainen-Määttä
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Markov Chain ◽  
Sulfuric Acid ◽  
Markov Chain Monte Carlo ◽  
Mass Spectrometer ◽  
Large Fraction ◽  
Cluster Formation ◽  
Unknown Parameters ◽  
Ammonia Clusters

Abstract. Evaporation rates of small negatively charged sulfuric acid–ammonia clusters are determined by combining detailed cluster formation simulations with cluster distributions measured at CLOUD. The analysis is performed by varying the evaporation rates with Markov chain Monte Carlo (MCMC), running cluster formation simulations with each new set of evaporation rates and comparing the obtained cluster distributions to the measurements. In a second set of simulations, the fragmentation of clusters in the mass spectrometer due to energetic collisions is studied by treating also the fragmentation probabilities as unknown parameters and varying them with MCMC. This second set of simulations results in a better fit to the experimental data, suggesting that a large fraction of the observed HSO4− and HSO4− ⋅ H2SO4 signals may result from fragmentation of larger clusters, most importantly the HSO4− ⋅ (H2SO4)2 trimer.

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