Showing papers on "Ullage published in 1977"

Development and Qualification of the Propellant Management System for Viking 75 Orbiter

Abstract: tube. This paper describes the development and qualification of the surface tension system and includes results of low-g drop tower tests of scale models, l-# simulation tests of low-g large ullage settling and liquid withdrawal, structural qualification tests, and propellant surface-tension/contact-angle studies. Subscale testing and analyses were used to evaluate the ability of the system to maintain or recover the desired propellant orientation following possible disturbances during the Viking mission. This effort included drop tower tests to demonstrate that valid wick paths exist for moving any displaced propellant back over the tank outlet. Variations in surface tension resulting from aging, temperature, and lubricant contamination were studied and the effects of surface finish, referee fluid exposure, aging, and lubricant contamination on contact angle were assessed. Results of movies of typical subscale drop tower tests and full scale slosh tests are discussed.

Liquefied gas tank and method of filling

Abstract: A liquefied gas tank having thermal insulation in association with a fluidtight body. A liquid supply line terminates at a location within the upper half of said vessel and discharges into a vertical draft-tube which is in fluid communication with the ullage portion of the vessel. The liquefied gas which is supplied into the draft-tube is conditioned to the pressure and temperature within the vessel as it travels downward to the bottom before it can flow radially outward into the tank.

Evaluation of Fluid Behavior in Spinning Toroidal Tanks

Abstract: An experimental study was conducted to evaluate propellant behavior in spinning toroidal tanks that could be used in a retropropulsion system of an advanced outer-planet Pioneer orbiter. Information on propellant slosh and settling and on ullage orientation and stability was obtained. The effects of axial acceleration, spin rate, spin-rate change, and spacecraft wobble, both singly and in combination, were evaluated using a Vs-scale transparent tank in \-g and low-g environments. Liquid loadings ranged from 5 to 96% full. The impact of a surfacetension acquisition device was assessed. Testing simulated the behavior of F 2 /N 2 H4 and N2O4/MMH propellants. Results are presented that indicate no major fluid behavior problems would be encountered with any of the four propellants in the toroidal tanks of a spin-stabilized orbiter spacecraft.

Design, fabrication, and testing of a full-scale breadboard nitrogen generator for fuel tank inerting application

Abstract: : Aircraft fuel tank ullage may contain a mixture of fuel vapor in air that presents a fire and explosion hazard. This hazard can be eliminated if the air is replaced by an inert gas containing insufficient oxygen to allow ignition. Fuel tank inerting systems using onboard storage of liquid nitrogen to supply the inert gas have been demonstrated by the FAA and others and have been retrofitted into some U. S. Air Force transport aircraft. Tests by NAFEC and the Air Force have shown that fuel ullage oxygen concentration must be reduced to 9 percent or less to protect against ignition sources. The use of hollow fiber permeable membranes in an onboard inert gas generator (IGG) fuel tank inerting system has been shown to be a feasible alternative to systems using stored liquid nitrogen, which must be periodically replenished. A program to optimize the permeable membrane geometry; generate data required for system design; and to design, fabricate, and test full-scale breadboard permeable membrane air separation modules was conducted using the McDonnell-Douglas DC-9 aircraft as a design baseline. Results of membrane development, full-scale breadboard module design, and testing are reported; a preliminary design is presented for a hollow fiber permeable membrane IGG system for the DC-9; and ownership considerations for the airborne system design, including a life cycle cost analysis, are discussed. (Author)

Design Criteria for Application of Membrane Nitrogen Inerting Systems to Army Aircraft Fuel Tanks

Abstract: : This report describes a study and development program to evaluate the application of a hollow fiber, permeable-membrane-based inert gas generation fuel tank inerting system to U.S. Army aircraft. The purpose of the system is to reduce the oxygen concentration in aircraft fuel tank ullage to an inert condition to eliminate the vulnerability of this volume to explosion and fire hazards associated with the presence of ignition source from hostile gunfire. Unlike some other fuel tank inerting systems, the inert gas generating system requires no regular resupply of expendables and does not add to the fuel tanks any materials that displace or retain fuel. Feasibility studies of system designs and aircraft penalties were evaluated for U.S. Army AH-1G, AAH, UH-1H, UTTAS, CH-47C, and OV-1D aircraft. Preliminary designs were prepared for systems for the following aircraft: AH-1G, CH-47C, and OV-1D (drop tanks only). The design of a flightworthy system was completed for the AH-1G Cobra helicopter.