Showing papers on "Ullage published in 1989"

Analysis of the nonvented fill of a 4.96-cubic-meter lightweight liquid hydrogen tank

Abstract: As part of its development of cryogenic fluid management techniques for spacecraft, the NASA Lewis Research Center Cryogenic Fluid Technology Office (CFTO) is planning to perform ground tests of nonvented fill techniques on a 4.96-cubic-meter lightweight liquid hydrogen tank. This tank is similar in size and shape to the tankage planned for CFTO's COLD-SAT liquid hydrogen flight experiment. The analyses used to select two injection systems are presented for nonvented fills of this tank at design flow rates between 220 and 450 kg/hr. The first system uses multiple nozzles spraying from the top of the tank through the ullage space. This system should be capable of liquid fill levels in excess of 95 percent. The second system injects the liquid through a submerged nozzle and should produce fill levels on the order of 80 percent liquid.

Ullage rod cleaner

Abstract: An ullage rod cleaning device includes a unitary, one-piece metal case and a unitary, one-piece foam rubber insert. The case includes brackets that are in abutting contact with edges of the insert, and has a magnet mounted thereon.

Oil level gauge

Abstract: An oil level gauge including an ullage rod that is segmented and retained as a unit by a tensioned cable and having a fluted surface in the fluid measuring area to assure accurate nonwiping reading of the oil level.

A Three Layer Model For Oil Tank Fires

Abstract: A three layer model for oil tank fires, which can be used to calculate heat transfer and burning rates more accurately, is studied theoretically and experimentally. It can also be used to explain the important role played by the ullage (or air space) in oil tank fires. The validity of this model has been established by burning jet fuel in an oil tank 1.6 m in diameter and 1.5 m high.

Direct drive gaseous hydrogen turbo actuator

Abstract: A propulsion engine (12) which combusts propellant received from the storage tank (24) in which a portion (28) of the tank contains propellant in the liquid state and in which an ullage (26) in a remaining portion of the tank contains the propellant in a gaseous state including a first propellant circuit (34) coupling liquid propellant stored in the tank to an evaporator (30); a second propellant circuit (36), coupling the gaseous propellant from the evaporator to the propulsion engine combustor and to the ullage; at least one power generating device (14 and 16) disposed in the second propellant circuit between the evaporator and the ullage, for providing a power output from energy of the gaseous propellant flowing in the second propellant circuit controlled by at least one control valve controlling a flow of gaseous propellant to the at least one device under the control of at least one valve control signal; a bypass circuit (40) coupled in parallel with the at least one power generating device containing a bypass valve (42) controlling flow of gaseous propellant through the bypass circuit from the evaporator to the ullage in response to a bypass valve control signal; and a controller (44) coupled to the bypass valve and the at least one control valve, for generating the valve control signal controlling the flow of gaseous propellant through the valves to produce a controlled mass flow of gaseous propellant into the ullage independent of variation of a mass of gas flow through the valves.

The Effects of Propellant Grain Fracture on the Interior Ballistics of Guns

Abstract: : The two-phase flow interior ballistic code XNOVAKTC (XKTC) has been modified to include the effects of propellant grain fracture. An increase in propellant surface is related to the level of intergranular stress in the propellant bed, caused either by local bed compaction associated with the ignition wave or by grain impact against, most likely, the projectile base. The user specifies the increase in propellant surface to be associated with the level of intergranular stress. An increase in local gas production follows directly from the increase in burning surface; interphase heat transfer and drag may similarly be linked to intergranular stress. This improved XKTC is used to illustrate the interior ballistic effects of grain fracture for two charges at two temperatures. Pressure waves in guns have long been linked to localized ignition and the distribution of ullage in the chamber; propellant fracture resulting from associated increases in intergranular stress are shown in this study to provide a link to higher breech pressures as well.

Storage of nuclear fuel

Abstract: To avoid build-up of an explosive mixture within the ullage space of a flask for irradiated nuclear fuel elements immersed in a caustic liquid an excess of hydrogen is produced in the flask by locating aluminium rods in the liquid. To control the reaction a corrosion resistant layer is applied to the rod with the exception of one end thereof. A suitable layer is a ceramic coating. The pH of the caustic liquid is also adjusted, suitably to a value of 12.4.

Pressure rise in a liquid fuel tank owing to volumetric heating

Abstract: Both the metallic casing and the liquid contents of a partially filled tank of a right-circular-cylinder configuration are subjected to a volumetric heating that is uniform in time and space, although the case and the liquid are heated at a different rate. The ullage includes the vapor of the h'quid, and also a fixed amount of an inert gas, present for purposes of pressurization; the gases are taken not to be subject to heating. A theoretical analysis is undertaken to predict the increase in pressure in time as a consequence of the heating, which, for example, might arise from the absorption of an incident particle beam. The increase in pressure is caused by two effects: 1) the differential expansion of the h'quid and casing as the temperature and pressure increase, and 2) the vaporization of some liquid to maintain saturation vapor pressure with an increase in temperature. The differential expansion is the mechanism for the large pressure rise for a small ullage; for a large ullage, the phase change is the more important mechanism, but the associated pressure rise is generally much smaller.

Atmospheric heating of vessels

Abstract: A design method is presented which predicts the maximum operating temperature of storage vessels exposed to atmospheric and solar heating containing liquefied gases, permanent gases or liquids. It is used to calculate the design pressure and/or minimum ullage of such vessels and will be published as an Australian Standard. The paper includes design curves and the derivation of some novel thermodynamic quantities.