%0 Journal Article %A Salizzoni, R. M. %A Hsieh, W. H. %D 1993 %I Begell House %N 1-6 %P 438-452 %R 10.1615/IntJEnergeticMaterialsChemProp.v2.i1-6.270 %T TEMPERATURE SENSITIVITY MEASUREMENTS AND REGRESSION BEHAVIOR OF A FAMILY OF BORON-BASED VERY HIGH BURNING RATE PROPELLANTS %U https://www.dl.begellhouse.com/journals/17bbb47e377ce023,181301e53c3359b9,5aadd2c81805d33a.html %V 2 %X The combustion behaviors of three formulations of very high burning rate (VHBR) propellants are being studied. These formulations contain 0, 2, and 4% boron hydride, B10H10, the burning rate catalyst. Two diagnostic tools were used in this study: a realtime X-ray radiography (RTR) system with a high-pressure double-windowed (HPDW) test rig and a pressure and temperature controlled optical strand burner (OSB). The RTR system is used to obtain instantaneous X-ray images of the solid propellant grain as it burns during a transient test at pressure up to 340 MPa (50,000 psi). The optical strand burner maintains a steady pressure up to 41.4 MPa (6,000 psi) and allows the initial temperature of the strand to be set from −40°C to +70°C (−40°F to + 158°F).
For a typical RTR test using the HPDW test rig, the instantaneous, internal burning surface of a center-perforated grain was observed. The results show that the grain remained as a consolidated piece even at a high regression rate of 200 cm/s. From these images, instantaneous burning rates were deduced for all three formulations. These burning rates were compared with earlier results obtained by the authors from end-burning grains under similar transient conditions. These two sets of burning rates are in reasonable agreement.
The OSB was used to study the temperature sensitivity (σp) of VHBR propellants. Determining propellants' temperature sensitivities as functions of pressure and temperature is important in the study of transient burning phenomena. It was found that σp increases as initial temperature (Ti) decreases. As a result of a slope break in the burning rate, σp exhibits discontinuities as functions of pressure and Ti.
From a recovered sample which was extinguished at 331 MPa (48,000 psi), the burning surface was found to be non-smooth and covered with a melt layer containing many small indentations. %8 1993-01-01