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 Title: The unsteady combustion of radiant heat flux-driven energetic solids Author(s): Son, Steven Forrest Doctoral Committee Chair(s): Brewster, M. Quinn Department / Program: Mechanical Science and Engineering Discipline: Mechanical Science and Engineering Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Engineering, Aerospace Engineering, Mechanical Abstract: An analytical and experimental investigation has been conducted on the unsteady combustion of energetic materials under dynamic radiant heating. Analysis has been carried out under the assumptions of quasi-steady gas and surface reaction, homogeneous propellant, and one-dimensional flame (QSHOD theory). Further, the assumption of a quasi-steady surface reaction was relaxed to consider the effects of a fully unsteady surface reaction zone. The analysis shows an effect of the mean radiant flux on the combustion response which has previously been neglected by most researchers in this area. The results also illustrate the importance of including in-depth absorption for typical wavelength-material combinations. The laser-recoil experimental technique has been further developed and demonstrated. Unsteady burning measurements of fine oxidizer composite (APF series) and a catalyzed double base (N5) propellants at 1 atm are reported. Both N5 and APF data sets show significant effects of the mean flux on the measured frequency response. The frequency response of the APF propellant exhibited two frequency response peaks under the conditions considered. The lower frequency peak is shown to correspond to the nonreacting thermal layer in the condensed phase. The higher frequency peak is shown experimentally to correspond to the surface reaction layer. Effects such as oxidizer size, selective absorption (wavelength effects), carbon addition, mechanical properties, and nonlinear effects were eliminated as possible causes of the higher frequency peak. Comparison was made with the developed theory. The measured heat flux frequency response, R$\sb{\rm q}$, can be transformed into the pressure frequency response, R$\sb{\rm p}$, using the linear QSHOD analysis developed in this study. Due to the effects of in-depth absorption and the mean heat flux level, the analysis shows that in general the relationship between pressure frequency response, R$\sb{\rm p}$, and the heat flux frequency response, R$\sb{\rm q}$, is somewhat more complicated than a constant scaling factor. Even for surface absorption, a constant scaling factor may sometimes be inadequate. Steady burning in the presence of a radiant flux has been considered briefly also. Issue Date: 1993 Type: Text Language: English URI: http://hdl.handle.net/2142/22800 Rights Information: Copyright 1993 Son, Steven Forrest Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9416437 OCLC Identifier: (UMI)AAI9416437
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