Missile Propulsion Laboratory

Laboratory, Israel

Missile Propulsion Laboratory

Laboratory, Israel

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Rahimi S.,Defense Systems | Rahimi S.,Advanced Defense Technologies | Peretz A.,Defense Systems | Peretz A.,Advanced Defense Technologies | And 2 more authors.
Journal of Propulsion and Power | Year: 2010

A study was conducted to demonstrate the rheological matching of fuel, oxidizer, and simulant gels using various gellants, separately or combined. An investigation of the effect of temperature on the rheological parameters of water-based and gel-propellant simulants, formulated by various gellant combinations at different ratios among them was presented. Various gels of hydrazine and JP-8 fuels, hydrogen peroxide oxidizer, and water-based simulant gels were prepared to conduct the investigations. The rheological characterization of selected fuel, oxidizer, and simulant gels was carried out using a TA-CSL2100 rotational rheometer with cone-and-plate and parallel-plates configurations. The existence of no-slip conditions during all experiments was verified. It was also demonstrated that the rheological parameters for these types of gels obtained in simple shear measurements agreed closely to those obtained in uniaxial elongation measurements.


Kunin A.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory | Greenberg J.B.,Technion - Israel Institute of Technology
Journal of Propulsion and Power | Year: 2010

Experimental evidence of the combustion process of an all-organic gel fuel droplet indicates that at a certain time after ignition, evaporation of the liquid fuel results in the formation of an elastic layer of high-viscosity gellant around the droplet, which prevents further vaporization. As a result, constantly expanding vapor bubbles are produced within the droplet. Eventually, the layer ruptures and jets of fuel vapor are released. A theoretical, time-dependent model of organic-gellant-based gel droplet combustion has been developed and numerically solved. The results indicate that the evaporation rate of the liquid fuel from the droplet surface depends on droplet size and strongly affects the thickness of the gellant layer. The tensile stress, applied to the gellant layer during the formation of the bubbles, reaches high levels in short periods of time and causes the droplet to rupture when it exceeds the layer material rupture stress. The stage during which the gellant layer is formed is almost three orders of magnitude longer than the stage of bubble formation and layer rupture. © 2010 by A. Kunin, B. Natan, and J. B.Greenberg.


Hassid S.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
Journal of Propulsion and Power | Year: 2013

The present study proposes a simple theoretical model for the hypergolic ignition of gel propellants. The model assumes that the ignition process is governed by the time it takes for the heat wave produced by the reaction to diffuse through the whole droplet, which is described by the classical conduction time constant. The proposed model is based on a prior work by F. A. Williams and is further developed. The results obtained exhibit realistic ignition times in the range of tenths of milliseconds that are in close agreement to those obtained in various experimental works. Copyright © 2013 by the von Karman Institute for Fluid.


Marvina L.,Technion - Israel Institute of Technology | Marvin V.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
50th Israel Annual Conference on Aerospace Sciences 2010 | Year: 2011

The influence of a Paraffin-HTPB mixture configuration on the mechanical properties and on the burning rate of hybrid rocket fuel has been studied. A mathematical model has been developed to evaluate the various effects. The mechanical properties of the paraffin-HTPB composite in layer or fiber forms are improving with increasing the HTPB volume fraction and depend on the specific fuel structure and the acting strain direction. The essential differences between pure paraffin and HTPB regression rates result in a strong dependence of the paraffin and HTPB layer composite regression rate on the paraffin volume fraction, the layer thicknesses and the vector of the oxidizer mass flux.


Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory | Perteghella V.,Technion - Israel Institute of Technology | Solomon Y.,Technion - Israel Institute of Technology
50th Israel Annual Conference on Aerospace Sciences 2010 | Year: 2011

The need for a storable, non-toxic and high energy pyrophoric propellant points towards the combination of kerosene with hydrogen peroxide. Hypergolic ignition of almost any fuel-oxidizer combination can be obtained by gelling one of the liquids and adding the proper material. The Theological characteristics of gels enable the suspension of reactive or catalyst particles, uniformly distributed in the fuel, without compromising the energetic performance of the system. In the present research, pyrophoric ignition was achieved for a 92% concentration hydrogen peroxide and a kerosene gel containing sodium borohydride particles. Ignition delay times of less than 10 μs were observed.


Marvin V.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
50th Israel Annual Conference on Aerospace Sciences 2010 | Year: 2011

The processes of heat transfer in the condensed layer of a burning metalized solid propellant and the aluminum particle collisions and adhesion leading to agglomerate formation have been studied. It is shown that the thermal properties of the condensed layer are changing with time. The temperature distribution and the aluminum particle adhesion strength change have been analyzed. The particle temperature can be different from the binder temperature, if the heat transfer to the particle is carried out not only through the binder. When the condensed layer is completely filled by particles, there is always an unbroken chain of particles that crosses the binder from the near-burning surface region to the condensed layer end, which serves as an additional heat supply. the media effective diffusivity can significantly exceed the binder diffusivity and one can expect the effect of "thermal breakdown" leading to further increase in the particle and binder temperatures excursion, and also increase in both the condensed layer thickness and residence time.


Kim S.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
53rd Israel Annual Conference on Aerospace Sciences 2013 | Year: 2013

A simulation of the internal reacting flow in a ducted rocket combustor at various conditions was conducted using a CFD code and the effect of the air inlet configuration was investigated. The carbon particles within the fuel rich gas stream were treated as a separated stream from the main fuel stream to reflect the influence of carbon particle reaction. The recirculation stream of the carbon particles and the burned carbon mass fraction were found to have a major effect on the temperature and on the combustion efficiency. The results indicate that a four-inlet combustor with inlet angle of 90° can be regarded the most effective configuration for the combustion efficiency in a full length combustor and the two-inlet combustor with inlet angle of 90° is expected to be more effective in a half length combustor.


Matsibeker E.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013

The flowfield of an aluminized Gel Fuel Ramjet combustor has been studied and solved numerically. A theoretical model of the combustor, which considers the pulsatile combustion of the gel fuel droplets in combination with the aluminum particles combustion has been developed. The model was solved numerically using the CFD code FLUENT and a parametric investigation was conducted. Gelled kerosene droplets and the aluminum particles were injected discretely to the burner flowfield. The gel droplet burning mechanism was modeled by modification of the droplet vaporization pressure with droplet lifetime and the aluminum particles were added separately from the fuel droplets downstream from the fuel injection. The current research results indicate that despite the pulsatile burning mechanism of the organic gellant-based gel kerosene droplets, the calculated temperature field in the combustor was found to be rather smooth. In general, the periodic burning of the gel droplets slightly lowers the combustor temperature.


Gafni G.,Technion - Israel Institute of Technology | Kuznetsov A.,Technion - Israel Institute of Technology | Har-Lev D.,Technion - Israel Institute of Technology | Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013

The high specific impulse of the ramjet engine, combined with the ability of a gel to carry metal particles, make the Gel Fuel Ramjet a most adequate solution for a mid-high range sustainer. The goal of the present study is to verify experimentally the feasibility of such a concept and to investigate the combustor performance. A test facility and a lab-scale motor have been designed and built to investigate the atomization, the ignition and the combustion processes of a gel hydrocarbon fuel with and without metal additives, as well as to check the ramjet combustor operation. The paper presents the experimental system in detail as well as the results of firing tests using liquid and gelled kerosene with and without aluminum. The c* efficiency of the gel fuel was found to be slightly lower than the ungelled, liquid kerosene. Maximum combustion temperature and efficiency of 2000 K and 90%, respectively, were achieved at Φ≈l using a kerosene-paraffin gel with Nickel coated aluminum. The adequate bypass ratio for that gel was found to be ~;0.7.


Natan B.,Technion - Israel Institute of Technology | Natan B.,Missile Propulsion Laboratory | Solomon Y.,Technion - Israel Institute of Technology | Solomon Y.,Missile Propulsion Laboratory | And 3 more authors.
Journal of Propulsion and Power | Year: 2011

A study was conducted to propose a nontoxic propellant, based on gelled kerosene in which catalyst or reactive particles were suspended and ignite hypergolically with an oxidizer. The investigations demonstrated that the existence of yield stress assures that particles was added without the effect of sedimentation. The kerosene and hydrogen peroxide (HP) combination was nonhypergolic by its nature without the presence of adequate catalytic material that can dissolved in kerosene. The use of silica gellant in kerosene enabled the mixing of sodium borohydride particles in the kerosene, as the silica-based gels were non-Newtonian with a long-term storage capability and the silica was compatible with the sodium borohydride. The experimental observations indicated that the idea of gelling kerosene and adding reactive particles that promoted hypergolic ignition with oxidizers was ignition with oxidizers was feasible and used in nontoxic rocket systems.

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