Visualization and Performance of Hybrid Rocket Solid Fuels in an Optical Cylindrical Combustor

摘要

The design and initial test results of an optical cylindrical combustor is examined in this paper. A variety of binders and energetic additives have been explored in the past as a means to increase hybrid rocket motor combustion performance, specifically regression rate and combustion efficiency. The ability to visually investigate the combustion process and flame zone is important for understanding how different fuels affect combustion performance. Existing optical chamber designs, such as a "slab burner," have proven useful, but find difficulty viewing the fuel surface and flame zone at conditions that match hybrid rocket motor operation, due to charring/fouling of the viewing windows. The optical cylindrical combustor design allows the viewing of the burning surface at mass flux ranges from 200 kg/s/m~2 to 450 kg/s/m~2 and at chamber pressure upwards of 1.7 MPa (250 psia). Hydroxyl-terminated polybutadiene and dicyclopentadiene are considered with gaseous oxygen. The initial test results reveal that the flame zone of a burning strand of fuel can be viewed at an average mass flux of ～200 kg/s/m~2 and a chamber pressure of ～0.85 MPa (125 psia). The flame boundary and surface boundary can be tracked temporally to reveal flame height and regression rate. Further testing is required to verify the current results.