Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
TEST BENCH FOR MEASURING THE REGRESSION RATE OF SOLID PROPELLANTS
Submission Author:
GIL ROBERTO VIEIRA. PINHEIRO , RJ , Brazil
Co-Authors:
GIL ROBERTO VIEIRA. PINHEIRO, Mylena Candido, Daniel Chalhub, José da Rocha Miranda Pontes, Leib Neubarth, Norberto Mangiavacchi, Rachel Manhães de Lucena, Maurício Ferrapontoff Lemos, ANA PAULA DA SILVA, Priscila Simões Teixeira Amaral, LAURILIO SILVA JUNIOR
Presenter: Maurício Ferrapontoff Lemos
doi://10.26678/ABCM.ENCIT2022.CIT22-0686
Abstract
This work presents a test bench design for linear burning tests of solid propellants. The Strand Burner Test is a technique to experimentally evaluate the linear burning rate of solid propellants samples. The propellant composition could be used in Base Bleed gas generators and rocket motors. Despite the simplicity of the measuring bench built, it achieved good accuracy and provided a quick test procedure, allowing to improve the process of improving the propellant formulation with ease. The test bench can be used in propellant research and quality control during propellant production. In this work, the test bench was used to evaluate and improve the grain formulation of Base Bleed gas generators, used to inject hot gases to decrease the base drag and increase the range of the projectiles. Base Bleed gas generators operate at a low chamber pressure, close to the projectile’s base pressure. Thus, the burning tests were performed under atmospheric pressure conditions. But the burn rate can be measured at lower or higher chamber pressures, found respectively in Base Bleed operating at high flight altitudes and in rocket combustion chambers, with the aid of a small pressure vessel. Requiring only two or three electrical wires for its operation, the pressure vessel design is simpler and more compact. The test bench was made entirely of stainless steel. The propellant grain is fixed on a special support and, as the propellant sample linearly deflagrates, a set of fine wire filaments open in sequence, changing the voltage of the measurement circuit, through a resistive divider, which generates a voltage signal that can be used to detect the flame position along the propellant test sample. An electronic module, using an Arduino microcontroller commands the grain ignition and measures the voltage signal. A computer is connected to the module, and a special script in MatLab, process the data, calculates the linear burning rate, and plot the Voltage x Time graph. It will be presented that the linear burn rate measured during the tests was compatible with the literature related to similar propellant formulations.
Keywords
Strand burner test, solid propellant, Regression Rate
