| Two new methods for determining the burn rate of solid propellant have been developed for the ultrasonic pulse-echo technique. These methods are digital as opposed to the analog method that had been used in the past. The work presented is an uncertainty analysis of the two new methods as well the old method. A previous uncertainty analysis assumed that the propagation time uncertainty was constant throughout the burn; however, this may not be the case. A parametric study was performed that varied the propagation time uncertainty over a range where it was thought to lie. Monte Carlo simulations were chosen because of their simplicity. The results showed that the uncertainty of the new digital methods, 4.2% to 5.7%, compared very well to the uncertainty of the analog method, 3.5% to 5%. An uncertainty analysis was also performed on the temperature sensitivity of the propellant. The results showed that uncertainty was high varying from 40% to 78% for the conditions investigated, but this could be attributed to the small number of samples that were tested. |
