Mhd natural convection flow of fluids

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Mhd natural convection flow of fluids

To keep the crew and the computers alive you have to shield them from both gamma rays and pions. As far as the crew is concerned both reaction products come under the heading of "deadly radiation. Given an absorbing propellant or radiation shield of a specific density you can figure the thickness that will stop all the pions.

This is the pion's "range" through that material. In table the columns under the yellow bar show how many centimeters the "range" of the given stopping material is required to absorb MeV of pion energy.

The two sets of orange bars is because while the range is relatively constant for all high energies, the range becomes dramatically less at the point where the pion energy drops below MeV the "last MeV".

But you only need 27 centimeters of water to absorb MeV from a 75 MeV pion. Since hydrogen, helium, and nitrogen have regrettably low densities the reaction chamber will have to operate at high pressure to get the density up to useful levels. The Space Shuttle engines operated at a pressure of atmospheres, is a bit excessive.

So of the gases nitrogen might be preferrable, even though you can get better specific impulse out of propellants with lower molecular weight. Range of charged pions from Antiproton Annihilation Propulsion Using more calculations that were not explained figure was produced.

The curve is the relative intensity of a charged pion at a given kinetic energy in MeV. The MeV pions are the most intense there are more of themthe average energy is MeV.

Mean Life is the lifespan not half-life of a pion at that energy in nanoseconds. The range of a pion at that energy can be measured on the RANGE scales below, traveling through vacuum, hydrogen H2 propellant at atm, nitrogen N2 propellant at atm, and tungsten radiation shielding.

Gamma Rays Sadly gamma rays cannot be used to propel the rocket well, actually there are a couple of strange designs that do use gammasall they do is kill anything living and destroy electronic equipment.

So you have to shield the crew and electronics with radiation shielding. This is one of the big drawbacks to antimatter rockets. Gamma-rays would be useful if you were using antimatter as some sort of weapon instead of propulsion.

A small number of "prompt" gamma-rays are produced directly from the annihilation reaction.


The prompt gammas have a whopping MeV, but they only contribute about 0. A much larger amount of "delayed" gamma-rays are produced by the neutral pions decaying 90 attoseconds after the antimatter reaction. As mentioned abovethe antimatter reaction is basically spitting out charged pions and gamma rays.

The pions can be absorbed by the propellant and their energy utilized. The gamma rays on the other hand are just an inconvenient blast of deadly radiation traveling in all directions.

The only redeeming feature is gamma rays are not neutrons, so at least they don't infect the ship structure with neutron embrittlement and turn the ship radioactive with neutron activation.

Since gamma rays are rays, not particles, they have that pesky exponential attenuation with shielding. It is like Zemo's paradox of Achilles and the tortoisemaking the radiation shielding thicker reduces the amount of gamma rays penetrating but no matter how thick it becomes the gamma leakage never quite goes to zero.

Particle shielding on the other hand have a thickness where nothing penetrates. Gamma rays with energies higher than MeV have a "attenuation coefficient" of about 0. Since tungsten has a density of Table gives the attunation for various thickness of tungsten radiation shields.

Fluid dynamics - Wikipedia

This tells us that a 2 centimeter thick shield would absorb The main things that have to be shielded are the crew, the electronics, the cryogenic tankage, and the magnetic coils if this particular antimatter engine utilzes coils.

The radiation flux will be pretty bad. Well, actually the report says megawatts so obviously I made a mistake somewhere. Anyway the thrust power basically is the fraction of the antimatter annihilation energy that becomes charged pions.

The coil coolant systems should be able to handle that. The superconducting coils do not care about the biological dose since the coils are already dead. But you do not get something for nothing. The 10 centimeters of coil shield prevent the radiation from hitting the coils but it does not make the radiation magically disappear.

The coil shield will need a large heat radiator system capable of rejecting You will need more to shadow shield the living crew and sensitive electronics.This effect is of importance in various areas of technology and engineering such as MHD flow meters, MHD power generation, and MHD pumps [1–4].

The study of the interaction of conducting fluids with electromagnetic phenomena is important and such problems . International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research. Ram and Takhar reported on the rotating natural convection MHD flow with Hall/ionslip current effects.

Ram et al. extended I. Pop, S. NakamuraLaminar boundary layer flow of power-law fluids over wavy surfaces. Acta Mech., (), pp. Treatise on Geophysics, Second Edition, is a comprehensive and in-depth study of the physics of the Earth beyond what any geophysics text has provided previously. Thoroughly revised and updated, it provides fundamental and state-of-the-art discussion of all aspects of geophysics.

Numerical Solutions of Double-Diffusive Natural Convection Flow of MHD Casson Fluid over a Stretching Vertical Surface with Thermal Radiation K.

Ganesh Kumar1, Oldroyd-B fluids, Casson fluid etc. have been formulated according to physical characteristics of . The time-dependent mixed bioconvection flow of an electrically conducting fluid between two infinite parallel plates in the presence of a magnetic field and a first-order chemical reaction is investigated.

The fully coupled nonlinear systems describing the total mass, momentum, thermal energy, mass diffusion, and microorganisms equations are reduced to a set of ordinary differential equations.

Mhd natural convection flow of fluids
American Scientific Publishers - Journal of Computational and Theoretical Nanoscience