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.

Measurement and Analysis of the Burning Rate of HAN‐Based Liquid Propellants

Abstract: A new device for measuring the linear burning rate of liquid propellants at high pressures is reported. High-pressure environments were generated by the combustion of solid propellants. The coated propellants, which burn progressively, were introduced to maintain the approximate constant-pressure environments. By use of ion probe transducers, measurements were made of the spread velocity of the flame surface, i.e. the apparent linear burning rate of the HAN-based liquid propellant LP1846 (HAN =hydroxylammonium nitrate) was measured quantitatively at pressures from 6 to 28 MPa. The results show that it follows the exponential burning rate law. The burning rate coefficient and exponent were fitted by least-squares methods. Based on the experiment, a simplified model of the linear burning rate of HAN-based liquid propellants at high pressures was developed. The numerical simulation is found to be in good agreement with the experimental data.

Burn rate testing apparatus

Abstract: An apparatus for testing the burn rate between two spaced apart points on a sample of material. It includes an angularly adjustable support holder, an electrically ignited torch supplied with an independent supply of oxygen, a flame shutter between the torch and the sample holder and photocells positioned to sense ignition of the test material and the rate of burn between two spaced apart points on the material.

Upgrades to the Closed Bomb Facility and Measurement of Propellant Burning Rate

Abstract: : Propellants are a class of materials designed to produce low molecular weight gases that can be used in guns, missiles, and pyrotechnics. The burn rate of a propellant is used to design such munitions systems. The preferred method for obtaining the burn rate is the constant volume closed bomb. The pressure-time history obtained in closed bomb experiments, coupled with a propellant's thermochemistry and geometry, is used to calculate the linear burn rate. The hardware and software previously used to record the data needed to calculate the linear burn rate were outdated. The software that controlled the closed bomb experiments required modification in order to integrate the command set of the new Agilent oscilloscope. The new program sends user-defined commands, reads data from an external voltage source, and arranges that data in the proper format for XLCB, the burn rate data reduction code written in house using Visual BASIC in Microsoft Excel. The new code improves efficiency by creating buffers, eliminating extraneous subroutines. The new software has been tested for accuracy against the previous program using a split signal and closed bomb tests. This report presents a brief overview of closed bomb testing, a detailed account of the program and programming process, and results confirming the accuracy of the new program.

Strain Rate Insensitivity of Damage‐Induced Surface Area in M30 and JA2 gun propellants

Abstract: : Uniaxial compression tests are performed at constant strain rate on single-grain, seven-perforated specimens of M30 and JA2 gun propellant using the US Army's high rate, servohydraulic test apparatus in order to investigate the effects of strain rate, temperature, and percent axial strain on the combustion characteristics (apparent burn rate and pressurization rate) of the propellants. At room temperature M30 primarily deforms by macroscopic fracture and JA2 deforms by macroscopic flow. The single grains of deformed propellant are then burned in a newly designed 7.8-cc mini closed-bomb and plots of pressure, pressurization rate and surface area ratio versus time, and apparent burn rate versus pressure are compared with baseline results for the undeformed propellant specimens. The apparent burn rates of damaged M30 propellant vary considerably and the degree of damage-induced surface area approaches six times that of the undeformed baseline M30 specimens. The apparent burn rates of JA2 are relatively unaffected by the induced deformation. Results of the statistical test design indicate that the apparent burn rate of JA2 at 20 MPa is primarily dependent on the deformation temperature, yet the apparent burn rate of M30 at 20 MPa is dependent primarily on percent axial specimen strain. The apparent burn rates for these propellants are relatively insensitive to the deformation strain rate over the range 0.01 to 100/sec.