Burn rate (chemistry)

About: Burn rate (chemistry) is a research topic. Over the lifetime, 847 publications have been published within this topic receiving 8908 citations. The topic is also known as: Burning rate.

Burning Performance of Grain-molded Propellant

Abstract: The effects of density of grain-molded gun propellant and surface treatment of based-propellant on combustion performance of the grain-molded gun propellant were studied by closed-bomb test and 30 mm simulation ballistic gun test using high energy grain nitramine propellant RGD7A-6/7 as based-propellant.The characteristics of p-t and L-B curves for grain-molded gun propellant with different modular densities and different surface treatment of based-propellant were analyzed.The influences of density and surface treatment on the combustion property of the grain-molded gun propellant were obtained.The results show that in the density range from 1.0 g·cm-3 to 1.5 g·cm-3,the higher the density of the grain-molded propellant is,the better its progressivity is.The progressivity of grain-molded gun propellant MD7 obtained with surface-deterred and then surface-coated for based-propellant is the best.The muzzle velocity of MD7 at chamber pressure of 29.7 MPa increases by 6.6%.The muzzle kinetic energy increases by 13.8%.

Flame Spreading and Combustion Behavior of Gun Propellants Packed in High Loading Densities

Abstract: : The combustion process of gun propellants packed in high loading density conditions can differ significantly from those burning individually in the same pressure and temperature environment. More specifically, burn rates and flame spreading processes for a propellant charge are not only functions of pressure and initial temperature, but also a function of the loading density (or gap width between adjacent propellants). This experimental study has been conducted to investigate the influence of gap space between propellants on propellant regression rates. In the experimental setup, two opposing strands of JA2 gun propellant were burned in a double-ended windowed strand burner (DEWSB). The DEWSB consists of two identical propellant feeding systems adjoined to a center combustion chamber. To measure the gap width between the two strands, a contrasting image between the propellant strands and the background was used. To obtain a constant gap width between the opposing propellants, an image was imported into a LabVIEW control feedback loop. A series of tests was conducted for a pressure range from 0.69 to 3.45 MPa, and a gap distance range from 2 to 12 mm. Comparing regression rate data of JA2 propellant burned in the double-end configuration to that of a single strand, an increase in the regression rate of about 30% was observed for the pressure range tested. This increase occurs for a certain gap width range, which was found to be a function of pressure. The enhancement of the burn rate is caused by the geometric confinement of the flame, which applies a greater energy feedback to the burning propellant surface.

Influence of Burning Rate Pressure Exponent of Propellant on Gun Interior Ballistics

Abstract: In order to study the interior ballistic behavior of new type high-energy propellant,influence of burning rate pressure exponent of propellant on gun interior ballistic behavior was theoretically simulated by classical interior ballistic mathematical model.The results show that the value of burning rate pressure exponent of propellant and its change law can bring about a great change of interior ballistic behavior.The new type high-energy propellant whose burning rate pressure exponent is decrescent as pressure increasing can obtain higher interior ballistic piezometric efficiency,and reduce the sensitivity of bore pressure and muzzle velocity on loaded conditions of propellant.It will appear an evident error when interior ballistic behaviors of this kind of high-energy propellant are evaluated by traditional average burning rate pressure exponent.

Co-Layered Propellant Charge

Abstract: The invention is directed to a co-layered propellant grain having an exposed outer surface, wherein said propellant grain comprises an outer layer comprising a slow burning propellant composition located on essentially the entire outer surface of the grain, and an inner layer comprising a fast burning propellant composition having a higher linear burn rate than said slow burning propellant composition; wherein said propellant grain has a structure such that after ignition, the inner layer becomes increasingly exposed at the outer surface

Numerical simulation for burning rate of GAP high-energy propellant

Abstract: The thermal and combustion characteristics of GAP were analyzed.The hypothesis about GAP decomposition in the initial stage of combustion was proposed.The burning rate equation of GAP and GAP high-energy propellant was derived based on the chemical structure.The calculated burning rates of GAP high-energy propellant agree well with most of the experimental data with the deviation of all data within±15% and that of a majority of data wihtin±10%.It proves that the model and program are reasonable.