Block of solid propellant with a coupling element for measuring the rate of combustion of the propellant using ultrasound; production of said block; measurement of said speed

摘要

The block (4) of solid propellant comprises an ultrasonic device fixed via a coupling element for measuring the speed of combustion of the solid propellant. The coupling element: is made of a polyurethane matrix and free of air bubbles; has a Shore D hardness of greater than 80; and contains mineral charges (35-45 mass%) of adequate quantity for providing an acoustic impedance of 3.2x 10 6kgm 2/s at a frequency of 1 MHz equal to the solid propellant and plasticizer and/or degassing agent. The mineral charges include metal sulfate and/or alkaline-earth sulfate. The block of solid propellant comprises an ultrasonic device fixed via a coupling element for measuring the speed of combustion of the solid propellant. The coupling element: is made of a polyurethane matrix and free of air bubbles; has a Shore D hardness of greater than 80; and contains mineral charges (35-45 mass%) of adequate quantity for providing an acoustic impedance of 3.2x 10 6kgm 2/s at a frequency of 1 MHz equal to the solid propellant and plasticizer and/or degassing agent. The mineral charges include metal sulfate, alkaline-earth sulfate, metal oxide, alkaline-earth oxide and/or mixture of charges, and have a density of greater than 4. Independent claims are included for: (1) a process for the elaboration of a block of solid propellant with a coupling element; and (2) a process for measuring the speed of combustion of the solid propellant.