Showing papers on "Ullage published in 2007"

Nitrogen inerting system for explosion prevention in aircraft fuel tank and oxygenating system for improving combustion efficiency of aerospace rockets/ aircraft engines

Abstract: Compressed Air from an aircraft/rocket engine's compressed air line to its air-conditioning system, or an Auxiliary Air Compressor out-put is used, for energizing a high-speed gas turbine. The very high-speed convoluting air discharge into a vortex cone causes a first separation of the Air gas components, by stratifying into heavier (Argon), medium (Oxygen) and lighter (Nitrogen) components, where in the heavier and lighter components are non-combustible, inert gases and the medium is a combustible gas. The lighter non-combustible component (Nitrogen) exits from the turbine in one direction for storage in the Inert gas tank. The heavier (Argon) and medium (Oxygen) components together move in the opposite direction for having a second stratifying separation downstream in the vortex tube, to separate non-combustible, heavier (Argon) gas from combustible medium (Oxygen) gas components. The combustible, medium (Oxygen) component exits the vortex tube open end, to flow into an Oxygenating storage tank; whereas, the heavier, non-combustible(Argon) gas is piped into the Inert gas storage tank. Both gas storage tank in-flow lines are fitted with non-return valves. The out flow lines from the Inert tank to either Fuel Tank “Ullage” or “OBGIS” areas are fitted with electronic control valves, operated by signals received from fiber-optic Temperature/Pressure/Oxygen concentration Sensors in the Fuel tank “Ullage” or “OBGIS: areas. Likewise, the outflow lines from the Oxygenating tank are fitted with electronc control valves activated by engine “takeoff” or Passenger cabin low oxygen signals, respectively.

CFD Modeling of Helium Pressurant Effects on Cryogenic Tank Pressure Rise Rates in Normal Gravity

Abstract: A recently developed computational fluid dynamics modeling capability for cryogenic tanks is used to simulate both self-pressurization from external heating and also depressurization from thermodynamic vent operation. Axisymmetric models using a modified version of the commercially available FLOW-3D software are used to simulate actual physical tests. The models assume an incompressible liquid phase with density that is a function of temperature only. A fully compressible formulation is used for the ullage gas mixture that contains both condensable vapor and a noncondensable gas component. The tests, conducted at the NASA Marshall Space Flight Center, include both liquid hydrogen and nitrogen in tanks with ullage gas mixtures of each liquid's vapor and helium. Pressure and temperature predictions from the model are compared to sensor measurements from the tests and a good agreement is achieved. This further establishes the accuracy of the developed FLOW-3D based modeling approach for cryogenic systems.

Control of vapor emissions from gasoline stations

Abstract: The present invention relates to a vapor recovery system for gas station that is capable of controlling vapor emission to less than 0.38 lbs/1000 gallons fuel dispensed. The system may include at least one canister containing adsorbents such as activated carbon, zeolite, activated alumina, silica, and other adsorbents for passive removal of hydrocarbon vapors in venting air. Additionally, the system may include a means to enhance vapor-liquid equilibrium in the ullage of the fuel tank and accordingly minimize vapor emission level.

Ullage pressure regulator

Abstract: A system for maintaining pressure in the liquid fuel tank of a high-speed flight vehicle, such as a hypersonic flight, scramjet powered air and space vehicle, manages tank ullage using a pressure regulator coupled to the fuel tank that supplies pressurized gaseous media into the fuel tank ullage based on the internal pressure of the tank. The regulator has an on-board controller that processes tank pressure input to deliver a pulse-width modulated input signal to the coil of the on-board solenoid metering assembly. Energizing the coil drives the metering valve open against spring force. The metering assembly is contained in a removable cartridge that has a floating valve guide that is held stationary by bias of the spring against the metering valve. The metering valve has a separate valve seat that mates with the metering orifice of a flow nozzle. The valve seat can have higher compressibility than a clapper part of the valve to effect a better seal, with its compression being controlled by contact of the clapper with a rigid stop surface of the flow nozzle.

Numerical Modeling of Propellant Boiloff in Cryogenic Storage Tank

Abstract: This Technical Memorandum (TM) describes the thermal modeling effort undertaken at Marshall Space Flight Center to support the Cryogenic Test Laboratory at Kennedy Space Center (KSC) for a study of insulation materials for cryogenic tanks in order to reduce propellant boiloff during long-term storage. The Generalized Fluid System Simulation program has been used to model boiloff in 1,000-L demonstration tanks built for testing the thermal performance of glass bubbles and perlite insulation. Numerical predictions of boiloff rate and ullage temperature have been compared with the measured data from the testing of demonstration tanks. A satisfactory comparison between measured and predicted data has been observed for both liquid nitrogen and hydrogen tests. Based on the experience gained with the modeling of the demonstration tanks, a numerical model of the liquid hydrogen storage tank at launch complex 39 at KSC was built. The predicted boiloff rate of hydrogen has been found to be in good agreement with observed field data. This TM describes three different models that have been developed during this period of study (March 2005 to June 2006), comparisons with test data, and results of parametric studies.

Transport-launching pack mainly for torpedo-type weapon

Abstract: FIELD: transport-launching packs for torpedoes. ^ SUBSTANCE: the transport=torpedo pack has a sealed body including a cylindrical shell with a destructible front cover and a domed bottom. The cylindrical shell is partially overlapped by the central cowling enveloping it with formation of a cavity that is filled with heat insulation. The bottom is provided with a shell enveloping the body with formation of a cavity that is filled with heat insulation. The sealed body, cylindrical cowling and the bottom shell are made of a composite material. The transport-launching pack also has a gas source for torpedo launch, torpedo retaining device, retaining device unlocking aid, electrical connectors of the electric coupling of the ship launch control system to the transport-launching pack, piling aid, temperature control system including a heating means, cooling aid and temperature-sensitive elements. A ullage motor is used in the transport-launching pack as a torpedo launch gas source. The sealed body of the transport-launching pack is made in the form of successively installed detachably joined to one another sections for placement of the torpedo, ullage motor, equipment of the cooling means respectively. The last section is also detachably joined to the bottom. The section for placement of the torpedo is made for sealing of its volume during operation of the ullage motor. The body of this section is made with inner centering guide components for the torpedo. The body of the section for placement of the torpedo near the front end face is made with an inside obturator in the form of a circular support. A collector ring is installed in the tail part of this section close to the cylindrical shell. The collector ring communicates with the section volume for placement of the torpedo by means of longitudinal ducts made in the centering guide components. The torpedo retaining aid is installed on the flange of the front end face of the body of the collector ring, and a seaped detachable partition is installed on the rear end face through a tight seal. The ullage motor is installed in cantilever on the partition, it is positioned inside the respective section. The cap of the ullage motor is passed through a hole in the partition, and the outlets of the ullage motor communicate with the volume of the section for placement of the torpedo. The unlocking aid of the torpedo retaining device includes a piston with a rod which are installed in the cap of the ullage motor for engagement of the rod tail end with the torpedo retaining device. The heating means has heating elements that are moulded in the material of the cylindrical shell in the area of the body section for placement of the torpedo. The equipment of the cooling means is installed in the respective section of the body of the transport-launching pack, and through an extended hollow component it communicates with the collector ring. The equipment of the cooling means includes an impeller for circulation of the refrigerant. The pilling aid is made in the form of aligned supports with engagement components for engagement with the mating engagement components of the launcher and/or supports of other transport-launching packs. ^ EFFECT: expanded possibility of torpedo use in various climatic zones. ^ 8 cl, 3 dwg