Industrial Adaptation of Ultrasonic Technique of Propellant Burning Rate Measurement Using Specimens

A method of solid-propellant burning rate measurement by ultrasonic technique using small cylindrical specimens was developed for routine measurements required in the solid-propellant manufacturing industry. The measurement procedure is discussed in detail. Emphasis is given to accuracy in measurements, ease of operation, minimization of manpower, and savings of cost and time. With this in view, new adaptations in specimen preparation, test procedure, and data processing are incorporated. Burning rates of more than 300 batches of aluminized ammonium perchlorate/hydroxyl-terminated polybutadiene composite propellant of three different compositions were measured. The results showed that the standard deviation in the measurements for a propellant batch was less than 1%. It was also demonstrated that the performance of full-size solid motors can be predicted with good accuracy by these burning rates with a small augmentation factor.