Search Results

You are looking at 1 - 10 of 14 items for :

  • "ignition delay" x
  • Refine by Access: All Content x
Clear All

Some transition metal nitrate complexes with hexamethylenetetramine

Part LV. Preparation, X-ray crystallography and thermal decomposition

Journal of Thermal Analysis and Calorimetry
Authors: G. Singh, B. Baranwal, I. Kapoor, D. Kumar, C. Singh, and R. Fröhlich

Abstract  

Three hexamethylenetetramine (HMTA) metal nitrate complexes such as [M(H2O)4(H2O-HMTA)2](NO3)·4H2O (where M=Co, Ni and Zn) have been prepared and characterized by X-ray crystallography. Their thermal decomposition have been studied by using dynamic, isothermal thermogravimery (TG) and differential thermal analysis (DTA). Kinetics of thermal decomposition was undertaken by applying model-fitting as well as isoconversional methods. The possible pathways of thermolysis have also been proposed. Ignition delay measurements have been carried out to investigate the response of these complexes under condition of rapid heating.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Gurdip Singh, A. K. Shrimal, Inder Pal Singh Kapoor, Chandra Prakash Singh, Dinesh Kumar, and Manan S. Mudi

the graph of metal complex) Ignition delay measurements Ignition delay ( D i ) at various temperatures was undertaken with the tube furnace [ 26 ]. The sample (mass 20

Restricted access

Fig. 7 Isothermal TG of complexes in static air The ignition delay ( D i ) or time ignition delay ( t id ) measurements were made on 20 mg samples (100–200 mesh) by using a tube

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Dumitru Oancea, Valentin Munteanu, Domnina Razus, and Maria Mitu

an S-shaped form, similar to the well-known conversion versus temperature variation (light-off curve) [ 26 ]. The recorded curves for the stoichiometric propane/air mixture have been used to measure the ignition delays and the steady-state reaction

Restricted access

Abstract  

The chemical stability of a propellant and its influence on the ballistic properties during aging is a subject of interest. The effect of aging on ballistic properties, viz., ignition delay, burning rate, and heat of combustion for an aluminised ammonium perchlorate–hydroxyl-terminated polybutadiene (AP/HTPB) composite propellant during accelerated aging were investigated. Samples of composite propellants were aged at 60 and 70 °C at relative humidity of 50% in a climatic chamber. The propellant samples were tested with pressurized nitrogen gas environment for ignition delay measurement. Test results indicate that aging does not have any appreciable effect on ignition delay. The change in ignition delay time is less than 3% within the scatter of the data. Experiment results indicate that burn rate do affect with pressure but aging does not have much effect on burn rate. It was also observed that the burning rate at low pressures did not undergo significant changes during the aging period. The most significant of all the ballistic properties of this propellant is the burning rate exponent which increased by about 10% during the aging period.

Restricted access

Abstract  

The nitrate complexes of copper, nickel and zinc with diethylenetriamine (dien) i.e. [Cu(dien)2](NO3)2, [Ni(dien)2](NO3)22H2O and [Zn(dien)2](NO3)2 have been prepared and characterised. Thermal studies were undertaken using TG-DTG, DSC, ignition delay (t id) and ignition temperature (IT) measurements. Impact sensitivity was measured using drop mass technique. The kinetic parameters for both non-isothermal and isothermal decomposition of the complexes were evaluated by employing Coats-Redfern (C-R) method and Avrami-Erofeev (A-E) equations (n=2 and 3), respectively. The kinetic analysis, using isothermal TG data, was also made on the basis of model free isoconversional method and plausible mechanistic pathways for their decomposition are proposed. Rapid process was assessed by ignition delay measurements. All these complexes were found to be insensitive towards impact of 2 kg mass hammer up to the height limit (110 cm) of the instrument used. The heat of reaction (?H) for each stage of decomposition was determined using DSC.

Restricted access

Abstract  

Two bis(bipyridine) polymeric metal nitrate complexes with 4,4’-bipyridine of simple formula like [M(bipy)2](NO3)2⋅xH2O (where M=Co, Ni and Cu; x=4, 2 and 0, respectively) have been prepared and characterized. Their thermal decomposition has been undertaken using simultaneous TG-DTG-DTA and DSC in nitrogen atmosphere and non-isothermal TG in air atmosphere. Isothermal TG has been performed at decomposition temperature range of the complexes to evaluate the kinetics of decomposition by applying model-fitting as well as isoconversional method. Possible mechanistic pathways have also been proposed for the thermolysis. Ignition delay measurements have been carried out to investigate the response of these complexes under the condition of rapid heating.

Restricted access

Abstract  

During the past several years, a significant effort has been on investigation of reaction front propagation and the rate of energy release in heterogeneous systems consisting of nanopowder reactants. Substantial size reduction of each reactant powder (e.g. from micro- to nano-size) leads to increase of reaction front propagation in some systems under unconfined conditions by approximately two to three order of magnitude. This paper presents key challenges associated with processing and use of nanothermite materials and characterization of nanoreactants. Reaction constants, such as activation energies and frequency factors were determined using DSC technique for several nanothermite systems based on nanosize aluminum and iron oxide, bismuth trioxide, and molybdenum trioxide. Experimental data of ignition delay times for different nanothermite systems using laser energy source were compared well to those predicted by proposed mathematical model.

Restricted access

); fuel injection pressure 10.3 MPa. The ignition delay was set to 13° by adjusting the compression ratio, so that combustion started at top dead centre (TDC) as specified by the American Society for Testing Materials (ASTM) 613. Table 1 shows the engine

Restricted access

). Induction periods The induction period (or ignition delay) τ i , measured between ≈150 ms and several seconds, depends on mixture composition, its total pressure p 0 , and wire temperature T w . A simple relationship giving the analytical form

Restricted access