Entity

Time filter

Source Type

Laboratory, Israel

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. Source


Kronhaus I.,Technion - Israel Institute of Technology | Kapulkin A.,Israel Electric | Balabanov V.,Asher Space Research Institute | Rubanovich M.,Israel Electric | And 2 more authors.
Journal of Propulsion and Power | Year: 2013

The coaxial magnetoisolated longitudinal anode concept was introduced to improve efficiency and lifetime of lowpower Hall thrusters (≤350 W). The coaxial magnetoisolated longitudinal anode represents a significant departure from conventional Hall thrusters and has not been thoroughly studied yet. The high efficiency of the thruster, as validated by measurements, increases the need for a better understanding of the physical processes in this type of thruster. An analysis of the coaxial magnetoisolated longitudinal anode discharge based on experimental measurements was conducted for this aim. The experimental setup includes electrical probes mounted on a fast moving positioner, enabling one to obtain the spatial distribution of plasma parameters inside the thruster channel. The results confirmed the basic assumptions used in the physical model of the coaxial magnetoisolated longitudinal anode concept and revealed new phenomena related to the radial nonuniformity of the discharge. In particular, focusing equipotentials were discovered not only in the anode cavity but also in the dielectric channel, where the area of intense ionization was located. The physical processes contributing to the formation of the focusing equipotentials are discussed. Copyright © 2013 by Igal Kronhaus. Source


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. Source


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. Source


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. Source

Discover hidden collaborations