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Experimental investigation into the L* instability of double base rocket propellants
Author(s) -
Schöyer H. F. R.,
De Boer R. S.
Publication year - 1978
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19780030303
Subject(s) - propellant , combustor , combustion , ignition system , rocket (weapon) , burn rate (chemistry) , mechanics , materials science , aerospace engineering , range (aeronautics) , instability , thermodynamics , nuclear engineering , acoustics , physics , chemistry , composite material , engineering
In a continuous joint research program, the Department of Aerospace Engineering of DUT and the Technological Laboratory TNO investigate unstable combustion of solid rocket propellants. Some results of this research program are discussed here. The oscillatory combustion phenomenon is discussed qualitatively, and the interaction between the acoustics of the cavity and the pyrolysis of the propellants is explained. For the investigation of the low‐frequency unstable combustion, a special device, the L* burner, is very suited. A description is given of the two L* burners of different size, which were used in the experiments discussed here. Reproducible ignition is of the utmost importance to conduct these tests. Various ignition methods have been tried and are described together with a very successful one, which was evaluated and finally selected. The experimental results of JPN and ARP propellant experiments are discussed extensively. Oscillatory combustion as well as chuffing has been observed, and it turns out that both phenomena are related to the L* and pressure. As L* burners of different sizes were used, it was possible to estimate the damping, and hence the propellant growth constant. On the basis of the results of these experiments it seems most likely that the damping is volumetric. It has been discovered that for a very large pressure range (∼ 3 MPa) the frequency of the oscillations is linearly dependent on the mean pressure, while at low pressures (<1 MPa) oscillations with a higher frequency, also dependent on the mean pressure, are observed. These observed pressurefrequency correlations are the same for the two L* burners of different size, and hence it may be concluded that these correlations are not affected by the dimensions of the motor cavity.