Homogeneous Ignition

Najt P.M. and Foster D.E. (1983) Compression-ignited homogeneous charge combustion. SAE Paper 830264. 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

Efficiency means component 1 made per component 3 converted, all in molar units. Data show that 89.7% of the converted propylene was accounted for by the formed acrolein. An additional 9.8% efficiency is indicated for acrylic acid. Efficiency to total useftil product was 99.5% as long as ignition of homogeneous reaction could be avoided... 

On the second startup no ignition in the bottom occurred, but it was observed here also that a significant drop in oxygen concentration occurred between the reactor bottom and the heat exchanger, without loss of acrolein concentration. The homogeneous reaction also produced acrolein, just in much lower selectivity. Then, on the third day of... 

Generally, at any moment of time the concentration of components within a vapor cloud is highly nonhomogeneous and fluctuates considerably. The degree of homogeneity of a fuel-air mixture largely determines whether the fuel-air mixture is able to maintain a detonative combustion process. This factor is a primary determinant of possible blast effects produced by a vapor cloud explosion upon ignition. It is, therefore, important to understand the basic mechanism of turbulent dispersion. 

Determination of iron as iron (III) oxide by initial formation of basic iron (III) formate Discussion. The precipitation of iron as iron(III) hydroxide by ammonia solution yields a gelatinous precipitate which is rather difficult to wash and to filter. Iron(III) can, however, be precipitated from homogeneous solution as a dense basic formate by the urea hydrolysis method. The precipitate obtained is more readily filtered and washed and adsorbs fewer impurities than that formed by other hydrolytic procedures. Ignition yields iron(III) oxide. 

Igniters. A mixt of 3kg of NC, 3.5kg of NG, and 400g of Centralite is homogenized with lOOg of dioctyl phthalate, 200g of dye, and 2.98kg of AP (particle size below 60y), and the mixt pressed into strands 1.5 mm in diam which can be used as an ign cord for rocket motors (Ref... 

Zhao, R, Homogeneous Charge Compression Ignition (HCCI) Engines, Warrendale, PA Society of Automotive Engineers, 2003. 

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