Авіаційно-космічна техніка та технологія (Aug 2017)
PRESSURIZATION SYSTEM OF THE TANK WITH OXYGEN VAPORS WITH CLEANING FROM COMBUSTION PRODUCTS
Abstract
Considered with respect to modern launch vehicles, the risks of using the once widespread systems of pressurization of tanks with liquid oxygen by its hot vapors. Such systems were successfully used at the Fau-2, at the second stage of the LV 63S1, the first stage of the Saturn-V LV. They do not require complicating the launch complex by means of refueling compressed gases onto the launch vehicle. When switching to engines with afterburning of oxidative gas, the situation worsened. The generator gas contains up to 5% of water vapor and carbon dioxide. In a cryogenic tank they can condense. In oxygen, after the high-pressure pump, there are also these components. They enter the oxygen after drive unit of the turbine of the booster pump. In general way, the condensed phase does not harm the pump. It causes concern among designers of systems of pressurization of tanks with oxygen due to the potential risk of a condensed phase. The purpose of the research is the safe use of oxygen vapors to boost the tanks initially containing a condensed phase. The most dangerous first tens of seconds of operation of the propulsion system were analyzed. Mass-exchange processes in the increasing free volume of a tank with oxygen are considered. The dynamics of the pressure variation of saturated water vapor in the tank and their partial pressure under a hot charge is studied. New possibilities for a sharp increase in the pressure of saturated water vapor in a tank are presented. New possible constructively simple ways of purifying the oxidative generating gas and liquid oxygen from the condensed phase are investigated. Recommendations have been worked out. Two possible principal schemes for eliminating the volume condensation of water vapor are presented and analyzed. To cope with surface condensation, a number of devices for introducing steam into the tank are proposed. Radically, the problem is solved when hot steam is injected into the tank in the form of turbulent vortex rings. The mass efficiency of steam systems with proposed schemes for purification from potential condensate is shown using the example of a tank with oxygen from a medium-sized launch vehicle.
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