Analysis of Quasi-Steady and Transient Burning of Hybrid Fuels in a Laboratory-Scale Burner by an Optical Technique

Burning of hydroxyl-terminated polybutadiene in gaseous oxygen is investigated using a timeresolved optical technique. Combustion tests are performed in a two-dimensional radial micro-burner under quasi-steady and forced transient operating conditions. Under quasi-steady operating conditions, the high initial regression rate at the beginning of the run is followed by a smooth monotonic decrease as combustion proceeds. This behavior is captured by a purposely developed regression rate simulation model. Under forced transient operating conditions, for oxidizer mass flow throttling down, solid fuel exhibits a non-monotonic regression rate response. Earlier phases of the transient are characterized by a noticeable regression rate decrease followed by faint oscillations.