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International Journal of Energetic Materials and Chemical Propulsion
ESCI SJR: 0.149 SNIP: 0.16 CiteScore™: 0.29

ISSN Print: 2150-766X
ISSN Online: 2150-7678

International Journal of Energetic Materials and Chemical Propulsion

DOI: 10.1615/IntJEnergeticMaterialsChemProp.v8.i2.50
pages 147-158


Hiroshi Hasegawa
NOF Corporation, Propellant and Explosive Research, Research and Development Department, Aichi Works, Taketoyo-Plant, 61-1, Kita-Komatsudani, Taketoyo, 470-2398, Aichi, Japan
Toru Shimada
ISAS, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan


In the case of center-perforated composite solid propellant grains, the radial linear burning rate often depends on web location. In many cases, the burning rate of the propellant in the middle of the web is highest along the radial direction. This distribution of the linear burning rate along the radial direction is called a midweb anomaly or hump effect. This phenomenon was researched in the 1980s in depth with many studies disclosed the mechanisms and causes. Recently, the spatial burning rate variation was measured directly with an ultrasonic device. Many studies have explained that oxidizer [ammonium perchlorate (AP)] particle orientation affects the magnitude of the linear burning rate. In addition, some studies showed that the burning rate anomaly depends on the burning direction. This phenomenon is practically important for the prediction of pressure-time history of a rocket motor with high accuracy. In this study, the midweb anomaly on a small center-perforated motor was investigated. The formulations of the sample propellants were similar to practical propellants. As a result of the motor firing test, pressure hump effect was measured. The burning rate anomaly along the web was estimated by the pressure hump effect and was dependent on the slurry casting process. In order to determine the directivity of the burning rate, it was measured along the motor