Arnold R.,Purdue University |
Arnold R.,Maurice J Zucrow Laboratories |
Santos P.H.S.,Purdue University |
Santos P.H.S.,225 South University Street |
And 3 more authors.
Journal of Propulsion and Power | Year: 2011
Rocket propulsion systems are bound to energetic propellant combinations to provide the best performance in conjunction with smallest possible storage volume. The application of a gelled fuel and a gelled oxidizer potentially combines the advantages of conventional solid and liquid propellants without some specific disadvantages of both individual systems. Gelled JP-8 and RP-1 fuels have been used to study the rheological behavior of gelled hydrocarbons. For all investigations fumed silica was used as a gelling agent with 4 to 7 wt%. Alongside a description of the gel mixing process, the paper discusses viscosity, stability, thixotropic behavior, and the viscoelastic properties of the gels through their storage and loss moduli as a function of gelling-agent amount. An extended Herschel- Bulkley model was applied to describe the viscosity characteristics of the hydrocarbon gels. Differential scanning calorimetry measurements showed only a slight influence of the gelling-agent amount on the heat of vaporization of the gels. The ungelled hydrocarbons featured a higher heat of vaporization than the gels. Copyright © 2010 by the authors.
Sardeshmukh S.V.,Purdue University |
Heister S.D.,Purdue University |
Heister S.D.,Maurice J Zucrow Laboratories |
Wang H.,Purdue University |
Sankaran V.,Air Force Research Lab
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013
Multi-phase ignition of hypergolic propellants Mono-methyl Hydrazine (MMH) and Red Fuming Nitric Acid (RFNA) is studied numerically to understand fundamental processes such as gas phase ignition, vaporization and liquid phase chemistry for characterizing ignition. Such understanding will be critical for future design efforts targeting rapidly repeatable cyclic ignition of these propellants. Three test cases are considered: gas and liquid phase autoignition, an opposed jet diffusion flame and a liquid opposed jet diffusion flame. For the first case, three reduced chemical kinetics mechanisms are used to study autoignition behavior in the gas phase and with premixed liquids. In the second case, a laminar diffusion flame of the gas phase reactants under varying strain rates is studied. The third case investigates the interface behavior for liquid-liquid contact and its effect on gas phase ignition.
Pfeil M.A.,Purdue University |
Kulkarni A.S.,Purdue University |
Ramachandran P.V.,Purdue University |
Son S.F.,Purdue University |
And 2 more authors.
Journal of Propulsion and Power | Year: 2016
An experimental study is conducted to evaluate amine-borane materials in solid fuels that create hypergolic combustion with nitric acid. Ignition delays as short as 3.3 ms have been measured for fuels containing amine-boranes in an epoxy binder: one of the fastest ignition delays ever recorded for a hypergolic hybrid fuel. The heats of formation of the amine-boranes were measured and theoretical (ideal) performance calculated. Some amine-boranes exhibit a double peak performance allowing for a range of oxidizer/fuel combinations resulting in high performance. Amine-borane/fuel binder combinations can produce a 3.8 and 8.2% increase in Isp and ρIsp, respectively, over monomethylhydrazine and a 4-11% increase in Isp and a 17% decrease to 5% increase in n ρIsp over other hypergolic hybrid rockets that use similar oxidizers. Amine-boranes also exhibit trends of being less toxic and more air stable than their base amines. In addition to the hypergolic properties, performance alone motivates the use of these materials, and it was found that amine-boranes could improve Isp by 2-6% and ρIsp by 1-11% compared with conventional rocket fuels, excluding liquid H2. Copyright © 2015 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc.
Cho K.Y.,Purdue University |
Cho K.Y.,Maurice J Zucrow Laboratories |
Pourpoint T.L.,Purdue University |
Pourpoint T.L.,Maurice J Zucrow Laboratories |
And 4 more authors.
Journal of Propulsion and Power | Year: 2013
Combustion of a nonmetallized organic gelled droplet was studied using high-speed (5 kHz) hydroxide planar laser induced fluorescence. Monomethylhydrazine was gelled with 3 and 6 wt%hydroxypropyl cellulose and burned in a pressure vessel with 35-414 kPa of ambient air. Fuel jetting is observed during the combustion of the gelled droplets. Three distinct types of jetting events were observed for the first time: 1) jets that distort the flame front, 2) jets that break the flame front, and 3) jets that form a fire ball outside of the flame front. The average jet speed was the highest for type 3 and the lowest for type 1. Speeds and locations of the fuel jets were quantified. It was observed that the radial jet velocity increases with increasing gellant concentration and decreases with increasing ambient pressure. Also, jets were observed to occur at the same location repeatedly. A possible explanation is that the initial jetting event weakens the shell, causing more jets to occur at the weakened location. Understanding the fuel jets of gelled droplet combustion is important because they are likely to influence the oxidizer-fuel ratio, chemical equilibrium, gas-phase mixing, and droplet trajectory in gel spray combustion. Copyright © 2013 by the von Karman Institute for Fluid.