نتایج جستجو برای: solid propellant
تعداد نتایج: 190589 فیلتر نتایج به سال:
Nitrate ester plasticized polyether (NEPE) is a new generation of composite solid propellants which its high energy content in comparing with conventional formulations, has attracted many researchers in the defense departments, all over the world. First of all an introduction and history and importance of NEPE propellants will be discussed and formulation and combination of propellants componen...
With the aim to reduce cost and increase reliability, MEMS technology penetrates space market and new MEMS components are developed for Space application. Among them, micropropulsion devices is an active field of technological research. Several micropropulsion option are under development : the thrust is produced either from a electrical source (electrical thruster) or a chemical source (chemic...
A method for the simulation of flows involving a disperse particle phase and a rarefied gas is extended for increased accuracy and efficiency in modeling the high altitude plume flow from a solid propellant rocket. First, a procedure is presented so that calculations involving the interphase transfer of momentum and energy may be avoided in regions where these calculations will have negligible ...
Research has shown that oscillatory or modulated flows can achieve a significant increase in heat transfer relative to the corresponding steady flow, providing that critical or threshold amplitude is achieved. The threshold condition is associated with the production of near-surface turbulence by the oscillatory motion. A similar process is hypothesized as a mechanism of highamplitude acoustic ...
Recent studies in solid composite propellants indicate that acceleration field cause to increase in burning rate. Relation between acceleration field and burning rate of propellant have an important effect on missile systems ballistic, especially on perforated grain missiles. If these effects has neglected in design phase, the pressure-time profile shifted out of acceptable rage and result in i...
Cracking is the breaking of bonds in a part of the propellant polymer due to the existing stresses that change the structure of the propellant polymer and they are classified into two general categories: macrocrack and microcrack. The service life of rocket engines is largely a function of the mechanical properties of the solid rocket propellant, the aging characteristics of the rocket propulsi...
Solid propellant burning rate is highly dependent on the pressure, so that the combustion duration propellant rocket engines, combustion vibration leads to considerable changes in pressure. This could lead to an explosion in rocket engines. The best case is propellant combustion independent of pressure. Ballistic modifiers added to propellant formulation for reduce pressure sensitivity and re...
The aims of this paper are review the effects of Propellant Formulation parameters and improving an understanding of mechanisms of burn rate temperature sensitivity. The initial temperature of a solid propellant influences the burn rate, pressure and thrust of the propulsion system. The temperature sensitivity, σp of solid propellant burn rate directly affects the accuracy and performance of th...
In this paper, diffusion and migration of Dioctyl sebacate (DOS) and Dioctyl phetalate (DOP) plasticizers at the interface of propellant and insulation as well as different distances from the interface in composite solid propellant based on HTPB / AP using both experimental and modeling have been investigated. Solid composite propellant and Nitrile Butadiene Rubber (NBR) insulation containing D...
In this study, a novel technique for evaluating continuously burning rate of cylindrical cores made of a solid homogeneous propellant is presented. The propellant core was placed in the tube made of pyrolytic graphite (pyrographite). The burning rate of the rocket propellant has been determined by monitoring the burning front/zone movement on the external surface of the pyrographite tube by usi...
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