Experimental Investigation of Pressure Dependency of Solid Propellant Sound Speed by Ultrasonic Technique
Author(s):
Abstract:
In order to determine accurate solid propellant burning rate by ultrasonic method، pressure dependency relationship of sample`s sound speed should be applied on thickness algorithm. This article presents comprehensive background in ultrasonic method and its application in burning rate measurement. Also pressure dependency of sound speed for several composite propellants based on HTPB had been investigated. Experimental samples with 30 mm length and 30 mm diameter had been tested under different pressure. The sound speed values were determined in each pressure by measuring the flight time of omitted ultrasonic waves and its returned echoes. The pressure varied from zero to 100 bar and the experiments were done for both pressurization and depressurization conditions. The results show that the samples sound speed depends slightly on pressure. Furthermore this relationship is linear. For instance it has been showed that pressure dependent for the speed of sound of HTPB sample had varied over 40 m/s for 1640 m/s average value. Other cases reviewed in this study were to evaluate the effect of pressure on sound speed for variety composition of HTPB with AL and AP particles. At the end some relevant experiments were done for uncertainty analysis of sound speed measurement. 3% uncertainty which is obtained for the sound speed measurements for HTPB is acceptable in comparison with other scientists` experimental results.
Language:
Persian
Published:
Aerospace Science and Technology Journal, Volume:2 Issue: 2, 2014
Pages:
46 to 59
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