RT Journal Article ID 6b6448387e857bb3 A1 Wada, Yutaka A1 Kawabata, Yo A1 Kato, Ryuichi A1 Kato, Nobuji A1 Hori, Keiichi T1 OBSERVATION OF COMBUSTION BEHAVIOR OF LOW MELTING TEMPERATURE FUEL FOR A HYBRID ROCKET USING DOUBLE SLAB MOTOR JF International Journal of Energetic Materials and Chemical Propulsion JO IJEMCP YR 2016 FD 2017-07-17 VO 15 IS 5 SP 351 OP 369 K1 traditional hybrid rocket K1 low melting thermoplastics K1 regression rate K1 nitrous oxide AB The hybrid rocket system is a promising next-generation space propulsion system owing to its low cost, high safety ability, and green characteristics. Conventional hybrid rocket systems have difficulty implementing large thrust motors owing to the low fuel regression rate. Studies regarding high regression rates of hybrid rocket fuel have been necessary for large motor designs. The high regression rate of low melting point fuels was confirmed in static firing tests by several researchers, where small droplets of the liquefied fuel were observed popping out from the burning surface using a slab motor in atmospheric conditions. However, the mechanism for the generation of small droplets from the fuel surface is unknown. The behavior of droplets under high pressure needs to be observed for a more thorough understanding of the combustion mechanism. In this study, a slab motor was prepared. Four fuel types, polymethyl methacrylate (PMMA), glycidyl azide polymer (GAP) mixture polyethylene glycol (PEG) fuel (GP fuel), WAX, and low melting point thermoplastics fuel (LT fuel), were selected as inert, high energy material, and low melting point fuels. The Katazen Corporation developed special LTs for this study to lower the melting point to a hot water temperature range. Visible light was eliminated to easily observe the surface behavior. An infrared filter was employed that allowed a wavelength of 760 nm or above to penetrate. No droplets were observed in the PMMA and GAP mixture PEG fuel combustion tests or during the Wax and LT fuel combustion tests conducted at 0.1 and 2 MPa. PB Begell House LK https://www.dl.begellhouse.com/journals/17bbb47e377ce023,568e196b14e53304,6b6448387e857bb3.html