Approved for public release; distribution is unlimited / An investigation into the behavior of aluminized solid propellant combustion in a two-dimensional windowed rocket motor was conducted using holographic techniques. Holograms were recorded in the motor port, aft of the propellant grain and at the entrance to the exhaust nozzle for two different propellant compositions at varying operating pressures. Quantitative particle size data for particles larger than 20 microns were obtained from the holograms. From these data, the mean diameters (D32) of the larger particles were calculated and utilized to compare what effects pressure, location in the motor and aluminum content had on the behavior of the aluminum/aluminum oxide particles. D 32 was found to decrease with increasing pressure, but was unaffected by variations in low values of propellant aluminum loading. D 32 at the grain exit was found to be significantly less than within the grain port. / http://archive.org/details/holographicinves00butl / Lieutenant, United States Navy

Composite propellants are composed of a solid oxidizer that is mixed into a hydrocarbon binder that when polymerized results in a solid mass capable of self-sustained combustion after ignition. Plateau propellants exhibit burning rate curves that do not follow the typical linear relationship between burning rate and pressure when plotted on a log-log scale, and because of this deviation their burning behavior is classified as anomalous burning. It is not unusual for solid-particle additives to be added to propellants in order to enhance burning rate or other properties. However, the effect of nano-size solid additives in these propellants is not fully understood or agreed upon within the research community. The current project set out to explore what possible variables were creating this result and to explore new additives. This thesis contains a literature review chronicling the last half-century of research to better understand the mechanisms that govern anomalous burning and to shed light on current research into plateau and related propellants. In addition to the review, a series of experiments investigating the use of nanoscale TiO2-based additives in AP-HTPB composite propellants was performed. The baseline propellant consisted of either 70% or 80% monomodal AP (223 μm) and 30% or 20% binder composed of IPDI-cured HTPB with Tepanol. Propellants’ burning rates were tested using a strand bomb between 500 and 2500 psi (34.0-170.1 atm). Analysis of the burning rate data shows that the crystal phase and synthesis method of the TiO2 additive are influential to plateau tailoring and to the apparent effectiveness of the additive in altering the burning rate of the composite propellant. Some of the discrepancy in the literature regarding the effectiveness of TiO2 as a tailoring additive may be due to differences in how the additive was produced. Doping the TiO2 with small amounts of metallic elements (Al, Fe, or Gd) showed additional effects on the burning rate that depend on the doping material and the amount of the dopant.

No description available.

Thesis (M.S.)--Ohio State University, 1986. / Includes bibliographical references (leaf 77).

A method for developing an erosive burning model for use in solid propellant design-and-analysis interior ballistics codes is described and evaluated. Using Direct Numerical Simulation, the primary mechanisms controlling erosive burning (turbulent heat transfer, and finite rate reactions) have been studied independently through the development of models using finite rate chemistry, and infinite rate chemistry. Both approaches are calibrated to strand burn rate data by modeling the propellant burning in an environment with no cross-flow, and adjusting thermophysical properties until the predicted regression rate matches test data. Subsequent runs are conducted where the cross-flow is increased from M=0.0 up to M=0.8. The resulting relationship of burn rate increase versus Mach Number is used in an interior ballistics analysis to compute the chamber pressure of an existing solid rocket motor. The resulting predictions are compared to static test data. Both the infinite rate model and the finite rate model show good agreement when compared to test data. The propellant considered is an AP/HTPB with an average AP particle size of 37 microns. The finite rate model shows that as the cross-flow increases, near wall vorticity increases due to the lifting of the boundary caused by the side injection of gases from the burning propellant surface. The point of maximum vorticity corresponds to the outer edge of the APd-binder flame. As the cross-flow increases, the APd-binder flame thickness becomes thinner; however, the point of highest reaction rate moves only slightly closer to the propellant surface. As such, the net increase of heat transfer to the propellant surface due to finite rate chemistry affects is small. This leads to the conclusion that augmentation of thermal transport properties and the resulting heat transfer increase due to turbulence dominates over combustion chemistry in the erosive burning problem. This conclusion is advantageous in the development of future models that can be calibrated to heat transfer conditions without the necessity for finite rate chemistry. These results are considered applicable for propellants with small, evenly distributed AP particles where the assumption of premixed APd-binder gases is reasonable.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 130-135). Available also in a digital version from Dissertation Abstracts.

No description available.

No description available.

This dissertation studies how nanoadditives influence burning rates through the development and use of a model to conduct parametric studies on nanoadditive interaction and to formulate theories. Decades of research have yet to determine the specific mechanisms for additive influence and the theories remain diverse and fragmented. It has been theorized that additives catalyze the combustion and thermal decomposition of AP, influence the condensed phases, and enhance the pyrolysis and regression of the binder. The main focus of the thesis was to approximate the enhanced boratory using spray-dried, spray-dried/heat-treated, and premixed TiO2 nanoadditives with ammonium perchlorate (AP) / hydroxyl-terminated polybutadiene (HTPB) composite propellants. The model is based on the classic Beckstead-Derr-Price (BDP) and Cohen-Strand models and contains a component that determines the pressure changes within the strand burner during a test. The model accurately predicts measured burning rates for baseline propellants without additives over a range of 500 - 3000 psi within 10%. The strand burner component of the model predicts the experimental pressure trace accurately. Further, the strand burner component determines an average burning rate over time and predicts a transient burning rate if provided a pressure trace. A parametric study with the model parameters determined that the nanoadditives appear to be increasing the AP condensed phase reaction rate. This conclusion was drawn because only changes in AP condensed-phase reaction rate would adequately and realistically replicate burning rate enhancements seen in laboratory experiments. Parametric studies with binder kinetics, binder regression rate, AP surface kinetics, and primary flame kinetics produced burning rate behavior that did not match that seen in experiments with the additives. The model was further used to develop a theory for how the nanoadditive affects the AP condensed phase, and a new parameter, (Omega)c, that influences the AP condensed phase reaction rate was created that replicates spray-dried, spray-dried/heat-treated, and premixed TiO2 nanoadditive experimental burning rates. Finally, the model was used to develop a first approximation of predicting anomalous burning rate trends such as a negative pressure dependence and extinguishment. A new term, Mc, that modifies the ratio of binder mass flux to oxidizer mass flux is used in tandem with (Omega)c to develop a negative burning rate trend that is close to the experimental result.

Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2010. / Thesis Advisor(s): Brophy, Christopher ; Second Reader: Gannon, Anthony. "June 2010." Description based on title screen as viewed on July 13, 2010. Author(s) subject terms: Solid rocket propellant, two phase flow, erosive burning, alumina agglomeration, laser imaging Includes bibliographical references (p. 87). Also available in print.