Burn-rate Measurement on Small-scale Rocket Motors

Small-scale rocket motors are widely used by propulsion industries to carry out burn ratemeasurement for a variety of needs. Several automated data-reduction procedures have beenimplemented to derive burn rate from pressure-time profiles resulting from experimentation. Evenif these are easy and fast to use, these procedures are not completely reliable in that thesemeasure only the average behaviour of a motor. A new model has recently been proposed toovercome this problem. However, it was soon noticed that the results depend on the propellantgrain production and forming processes even if the motor hardware is the same. A series ofpropellant grains has been produced to be sampled to map the local ballistic behaviour andchanges introduced by the manufacturing process. In this study, sampling and testing proceduresare reported and the results of an almost complete grain mapping are discussed