Burst Process of Spherical Aerial Shells

Y. Takishita, H. Shibamoto, T. Matsuzaki, K. Chida, F. Hosoya, and N. Kubota*

ABSTRACT: The burst process of spherical fireworks shells has been examined experimentally and presented as a simplified physical model. The pressure in a shell was measured with a straintype pressure transducer, which was inserted into the center of the shell. After the ignition of the bursting powder, pressure increased exponentially and the pressure also decreased exponentially, when the shell burst. The analysis of the pressure-versus-time curve indicated that the acting force on the stars in the shell was found to be dependent on various physical parameters: 1) the shape and material of the shell, 2) the characteristics of the bursting charge, and 3) the stars in the shell. The bursting process proposed in this study was confirmed by the observed ejection process of the stars in a Japanese-style, “warimono”* spherical shaped shell. *A spherical shaped shell containing stars and bursting charge that produces a chrysanthemum- flower shaped display in sky. [1]

Keywords: spherical aerial shell, burst process, pressure impulse, star acceleration


Ref: JPyro, Issue 10, 1999, pp1-6
(J10_1)

© Journal of Pyrotechnics and CarnDu Ltd



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