High-Pressure Testing Of Composite Solid Propellant Mixtures: Burner Facility Characterization

Much Research on composite solid propellants has been performed over the past few decades and much progress has been made, yet many of the fundamental processes are still unknown, and the development of new propellants remains highly empirical. Ways to enhance the performance of solid propellants for rocket and other applications continue to be explored experimentally, including the effects of various additives and the impact of fuel and oxidizer particle sizes on burning behavior. One established method to measure the burn rate of composite propellant mixtures in a controlled laboratory setting is to use a constant-volume bomb, or strand burner. To provide high-pressure burn rate data at pressures up to 360 atm, the authors have installed and characterized a new strand burner facility at the University of Central Florida. Details on the new facility and the measurement procedures are summarized. Repeatability between different batches of the same mixture has been demonstrated to be very good, and two common HTPB/Ammonium Perchlorate (AP) propellant mixtures containing 7/3 and 5/5 bimodal AP distributions were tested in the burner. The resulting burn rates are compared to data from the literature with good agreement in burn rate exponent and the impact of changing from a 7/3 to a 5/5 AP split