http://worldcat.org/entity/work/id/137588916

On propellant surface temperatures derived from calorimetry

Propellant surface temperatures for double base (JA2) and nitramine (XM39) propellant samples burning at pressures from 0.8 to 4 MPa have been measured using two different calorimetric techniques. The methods differ in the way combustion is extinguished; one involves depressurization, and the other involves burning into an inert base. For the experiments based on depressurization, a main source of uncertainty was in determining the area of the combusting surface. Moreover, this technique was prone to a large number of unproductive runs. Most of the data presented here was obtained from experiments in which combustion was extinguished by burning into a PolyEtherEtherKetone (PEEK) base. This robust material has thermophysical properties similar to the propellants studied. At higher pressures (and mass regression rates), radiative heating made nonnegligible contributions to total heat input to the inert base. Thus, a multivariate least squares model was developed to describe a time-dependent radiative and conductive heat input, and it was used to fit the experimental temperature histories. Propellant surface temperatures, radiative fluxes, and optical absorption coefficients are obtained from the fit to the data. For the regions of low mass regression rates (<0.7 g/sq cm-sec), the propellant surface temperatures were in agreement with published values. At larger mass regression rates, the propellant surface temperatures were larger than published values. This was believed to be a consequence of the way contributions from radiative heating were treated.

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