Flame structure of ap/binder sandwiches from emission imaging

Initial emission imaging experiments have been performed to directly investigate the flame structurej above sandwiches of ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene binder. All samples were tested under nitrogen, pressurized from 50 to 380 psig (0.34 to 2.6 MPa). Binder laminae from 100 to 450 urn thick were sandwiched between laminae of pressed AP. A narrowband (10 nm FWHM) dielectric filter centered at 310 nm was used to attempt to limitj the detected signal to chemiluminescent emission, from electronically excited OH, an indicator of chemical reaction. Initial results with moderately thin (100 μm) binder at 50 psig (0.34 MPa) show a strong diffusion flame and weak, lean, partially premixed side branches, forming a tribrachial or triple flame structure. At 380 psig (2.6 MPa) the premixed side branches are no longer resolved, but the center diffusion flame splits at the base to anchor on the AP side of both AP/binder interfaces. At 50 psig, with thick binder (450 um), the flame becomes more complex, with structures anchored at both AP/binder interfaces.