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.

Method for burning rate characterization of solid propellants

Abstract: A method for determining the burning rate of a propellant. The method involves the single firing of a subscale, propellant motor that has been modified so that the propellant motor has a tapered cylindrical port that produces a non-neutral pressure-time trace when burned. The pressure-time trace is initially progressive (pressure increases with time), and then regressive (pressure decreases with time). Unlike conventional motors, this motor operates over a range of burning rates; therefore, the burning rate behavior of the propellant can be characterized with a single motor firing. The burning rate of the propellant is extracted from the motor pressure-time history by a computer analysis package. The analysis package employs an optimization program which uses an internal ballistics model of the motor. The ballistics model is used to generate a theoretical pressure-time trace which can be compared with the digitized output signal from the actual motor. The optimization routine of the computer determines the propellant burning rate behavior by selecting the burning rate law which, when employed in the internal ballistics model of the motor, produces the best match between the computer generated and the actual motor pressure-time traces. Thus by using the tapered port motor and by reducing the data, the burning rate of a propellant can be characterized with a single motor firing.

Interaction of Capillary Plasma with Double-Base and Composite Propellants

Abstract: Experiments were conducted to characterize the electrothermal capillary plasma and its interaction with a double-base propellant, JA2, and two nitramine composite propellants, M43 and XM39, in closed-chamber and open-air conditions. Pressure-time histories were recorded during ignition and burning of the propellants in the closed chamber. Experimental results indicate significant differences in ignition and combustion of the propellants. The composite propellants exhibited a two-stage burning behavior: one stage of rapid burning driven by the plasma and a second stage of slower self-sustained burning, which occurred with a clear delay after the first stage. During the burning that is driven by the plasma, the burn rate was largely independent of propellant type. Optical microscopic images of recovered propellant samples showed clear physical changes in surface and possibly in subsurface structure, an indication of in-depth melting, vaporization, and possibly chemical reactions. Plasma-induced mass losses for the three propellants were obtained from open-air testing and compared to the values calculated based on the pressure data from closed-chamber tests.