Propellant precondition processes and the ways of their improvement
Aerospace propulsion engineering
Design Bureau «Yuzhnoye» named after M.K. Yangel, 3, Krivorozhskaya str., Dniepropetrovsk, 49008, Ukraine
The assignment of some flying vehicle (F/V) sets specific conditions for propellants gassing — Nitrogen Tetroxide (NTO) and Unsymmetrical Dime-thylhydrazine (UDMH). For example, for space crafts it is strongly recommended the fuel has no dissolved gas. F/V assigned for permanent standby in a wide range of environment temperature drop, should be filled with propellant of certain gas rate concentration in it.
A range of technological methods are accepted all over the world to solve this problem. The most widespread methods are: for degassing — vacuum gas volume, heat release, bubbling under the vacuum; for gas saturation — mixing, bubbling, fuel spraying.
Basing on analysis results it is easy to see that each degassing and gas saturation method has a range of disadvantages. They are process duration, huge vapor loss.
While designing a modern filling system it is necessary to develop new highly effective technologies along with structural variations which permit to speed up the propellant degassing and gas saturation process with low medium loses (fuel, compressed gas).
To solve this problem authors performed an analysis of principles for increasing the heat and mass exchange efficiency which are basing on the following concepts: increasing of phase contact surface; increasing of mixing performance; improvement of phase contact process; using of unsteady interphase exchange regimes which allow to reach the immediate values of mass exchange coefficients; performing a mass exchange processes within the hydrodynamic instability of interphase surface.
Finally a new easy technology was suggested — fuel bubbling through the gas-jet rod radiators. Structural and metering characteristics of device also as a time span for a mass exchange processes were estimated for applying this technology.
Specific recommendations were given for efficiently applying this technology
Installation of gas-jet rod ultrasound radiators in a tank provides an efficient propellant mixing by means of high medium turbulization which splits the gas bubbles and intensify the mass exchange.
Gas-jet rod ultrasound radiators allow to reduce the propellant processing period and minimize the medium loses (fuel, compressed gas).
Keywords:mass exchange, nitrogen tetroxide, unsymmetrical dimethylhydrazine, degassing, satiation, gas-jet rod radiator, concentration, nitrogen, helium
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