年間 6 号発行
ISSN 印刷: 2150-766X
ISSN オンライン: 2150-7678
Indexed in
DETERMINATION OF SOLID PROPELLANT BURNING RATE SENSITIVITY TO THE INITIAL TEMPERATURE BY THE ULTRASONIC METHOD
要約
Missile operating characteristics depend strongly on the solid-propellant burning rate sensitivity to the initial temperature, thus it is an important parameter for the propellant manufacturer and the missile designer. Obtaining the sensitivity to initial temperature requires determination of the burning rate with accuracy and running tests through the acceptance specification temperature range.
Nowadays, firing solid-propellant rocket motors with large grains at various initial temperatures is considered too expensive. Only a limited number of tests are made. The burning rate values are deduced from the pressure data with an indirect method specific to each manufacturer. The data obtained are mean values.
At ONERA, an ultrasonic method is applied successfully to determine solid-propellant burning rates at room temperature.[1,2,3] Accuracy is fairly good, but the method cannot be used at various initial temperatures because of wave propagation condition variations with temperature and the unacceptable behavior of the commercial ultrasonic transducer at low temperatures.
The work presented here is the result of a program established to develop ultrasonic method at different initial temperatures in the range of −40°C, +60°C. This work started with the development of an ultrasonic transducer usable at low temperature, followed by determination of ultrasonic wave velocities and dampings in a large temperature range for selected propellants and coupling materials. Finally, the ultrasonic method has been applied to burning tests in a thermally regulated closed vessel.