Showing papers on "Ullage published in 2002"

On-board fuel inerting system

Abstract: An inerting system is disclosed that is adaptable to inert the fuel tank of a vehicle, most typically an aircraft, that includes an oxygen detector to monitor the oxygen partial pressure of the vapors in the ullage (i.e., the overfuel) volume of the tank, a source of an inert gas (e.g., nitrogen) in valved communication with the ullage of the tank, and a detector for sensing the oxygen content in the ullage of the tank and controlling the flow of inert gas to the tillage to maintain that volume with a proportion oxygen that will not support combustion in the event of an ignition source or intrusion of another potentially explosive occurrence within said tank. A specific fiberoptic probe which enables monitoring oxygen content within the tank without introducing a source of electrical current within the tank is also disclosed.

Natural gas supply apparatus

Abstract: Apparatus for supplying natural gas fuel to heat the boilers of an ocean-going tanker for the transport of liquefied natural gas (LNG) comprises a compressor having an inlet communicating with the ullage space of at least one LNG storage tank and an outlet communicating with a conduit leading from the compressor to fuel burners associated with the boilers, and a forced LNG vaporiser having an inlet communicating with a liquid storage region of the said tank and an outlet communicating with the same or a different conduit leading to fuel burners associated with the boilers.

Multiphase cfd simulations of solid propellant combustion in gun systems

Abstract: The Army Research Laboratory has developed a scaleable, 3D, multiphase, computational fluid dynamics (CFD) code with application to gun propulsion (interior ballistics) modeling. The NGEN3 code, which incorporates general continuum equations along with auxiliary relations into a modular code structure, is readily transportable between computer architectures and is applicable to a wide variety of gun propulsion systems. Two such systems are the Army's Modular Artillery Charge System (MACS) and the Future Combat System (FCS). The MACS is being developed for indirect fire cannon on both current and developing (e.g., Crusader) systems. The efficiency of the MACS charge is dependent on proper flamespreading through the propellant modules; a process that has been repeatedly demonstrated in gun firings, successfully photographed using the ARL ballistics simulator, and numerically modeled using the NGEN3 code. The FCS requires weapons systems exhibiting increased range and accuracy. One of the technologies under investigation to achieve these goals is the electrothermal-chemical (ETC) propulsion concept, in which electrically generated plasma is injected into the gun chamber igniting the high-loadingdensity (HLD) solid propellant charge. NGEN3 code development and application to the MACS and FCS is currently a DoD HPC Challenge Project (No. 112) and is being greatly advanced by access to the DoD high performance computers (HPCs). Associate Fellow AIAA. Propulsion Physics Team Leader, Ballistics and Weapons Concepts Division, Weapons and Materials Research Directorate. Mechanical Engineer, Propulsion Physics Team, Ballistics and Weapons Concepts Division, Weapons and Materials Research Directorate. This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States. INTRODUCTION A solid propellant gun system consists of a reaction chamber connected to a gun tube through which a projectile is guided once propelled by pressurization of the chamber. Chamber pressurization is accomplished by placing a solid propellant (SP) charge in the chamber and igniting it by various means. Current SP charges are generally complex structures consisting of hundreds or even thousands of distinct regularly formed (e.g., spherical, cylindrical) grains, which may be loaded in either regular or random arrangements. In addition to small-scale voidage between grains (i.e., porosity) many charges also contain large-scale voidage (i.e., ullage), which surrounds the entire charge (such as when the charge does not fill the entire chamber volume) or separates distinct subcharges (i.e., increments or modules) that together comprise the whole charge. The addition of energy to the chamber, usually near the gun breech, or rearmost end of the chamber, and in some cases through a tube extending along the centerline of the chamber, ignites the SP. In general, all of the grains are not ignited simultaneously, but an ignition flame spreads from the breech to the projectile base. The burning of the SP transforms chemical energy into heat as hot gases evolve from the surface of each grain of propellant. Initially the projectile resists movement allowing the pressure in the chamber to climb rapidly. Since the burn rate of the propellant is proportional to the pressure, hot gases are produced at an accelerated rate until peak pressure is reached in the chamber. Movement of the projectile down the gun tube, usually slight before peak pressure and much more significant afterwards, causes the chamber volume to increase, and generates rarefaction waves, which lower the pressure and thus the burn rate of the propellant. Upon ignition and burning, the gas dynamic flowfield in the gun chamber takes on a highly complex structure that includes the dynamics of propellant motion and combustion and various gas dynamic flow phenomena such as turbulent mixing, highly transient pressure waves, steep gradients in porosity and temperature, nonideal thermodynamics, and gas generation.

Method and plant for discharging a liquefied gas between a mobile supply tank and a service container

Abstract: Supply of liquefied gases. The plant is characterized in that: • the withdrawal outlet is provided with a transfer pump (16) and with an ejector (17) which are located upstream of the fitting (11); • the ullage space of the container is equipped with a gas phase recycling line (5) equipped with a fitting (15); and • heat exchange means (19) are interposed in order to: - condense all or a portion of the recycled gas phase from the container and reinject it in liquid form into the ejector where any further condensation is completed, - vaporize a portion of the liquid phase from the tank in order to maintain the gas phase occupying the ullage space of the latter. Application to the filling of several containers by a mobile tank.

Method and system for evaporative leak detection for a vehicle fuel system

Abstract: A vapor leak detection method and system is provided. The detection method comprises: sealing an ullage; purging fuel vapors of the sealed ullage into an air intake system for a predetermined period so that a negative pressure is formed in the ullage; and determining if the ullage has a leak, based on changes of the negative pressure in the ullage. The system includes a pressure sensor for detecting pressure in the ullage of a fuel tank; a canister that collects volatile fuel vapors from the ullage that were generated by the vaporization of liquid fuel; a purge control solenoid valve for directing fuel vapors into an air intake system; a canister close valve for selectively venting the ullage to atmosphere; and an engine control unit implementing the method.

Restrictor and air conditioner

Abstract: PROBLEM TO BE SOLVED: To reduce rubbing noise of refrigerant without causing any variation in the flow rate of refrigerant due to clogging of a restriction passage with a mixing matter even in case of long term use. SOLUTION: In the inner passage of a valve element 17 opening toward a valve chamber 14 on one side and toward a valve port 15 on the other side and interconnecting the valve chamber 14 and a second inlet/outlet port 13 under closed state, a filter element (a porous member 19 having a large ullage) for capturing a mixing matter, an orifice member 22, and a porous member 23 having a small ullage for reducing the flowing noise of fluid are arranged sequentially.

Investigations into tank venting for propellant resupply

Abstract: Models and simulations have been developed and applied to the evaluation of propellant tank ullage venting, which is integral to one approach for propellant resupply. The analytical effort was instrumental in identifying issues associated with resupply objectives, and it was used to help develop an operational procedure to accomplish the desired propellant transfer for a particular storable bipropellant system. Work on the project was not completed, and several topics have been identified as requiring further study; these include the potential for liquid entrainment during the low-g and thermal/freezing effects in the vent line and orifice. Verification of the feasibility of this propellant venting and resupply approach still requires additional analyses as well as testing to investigate the fluid and thermodynamic phenomena involved.

Parametric Optimization of Electrothermal-chemical (ETC) Launchers

Abstract: The research on a 30 mm electrothermal-chemical (ETC) gun including theoretical simulation and experimental results is presented in this paper The predictions of the theoretical model which is composed of three parts (ie, pulse forming network, plasma generator and interior ballistics) are in good agreement with the experiments In addition, we have performed some liquid propellant and solid propellant experiments, respectively Among the solid propellant experiments, we have investigated the ignition modes of propellant and high velocity launchers As a result, the 25: 75 mixture of octane and hydrogen peroxide has a better effect than other liquid propellants When the propellants are ignited nearby the bottom of projectile in chamber by using an ullage tube connected with the plasma generator, the kinetic energy of projectile will increase, while the chamber pressure will decrease With a total input electrical energy of 180 kJ, the exit velocity of projectile is up to 21 km/s or so

Ground-Based Inerting of Commercial Transport Aircraft Fuel Tanks

Abstract: Extensive research has been performed by the Federal Aviation Administration to help develop practical and cost-effective inerting systems for commercial transport airplane fuel tanks. The concept of ground-based inerting has been studied in the laboratory and on two different aircraft in an attempt to develop a costeffective methodology for fuel tank inerting. These research projects studied inert gas requirements, effects of adjacent fuel loads, oxygen concentration requirements, modeling of inert gas flow, and full-scale flight and ground center wing tank inerting. The results indicate that fuel tanks can be inerted efficiently with nitrogenenriched air and that adjacent unscrubbed fuel loads would have very little effect on the inert ullage compared to the effect of fuel usage. Although some data illustrated that inert gas distribution could be problematic under some inerting conditions, results indicate that inerting was predictable and efficient and could be modeled, provided attention is given to vertical mixing. Aircraft inerted on the ground maintained a significant benefit during ground and flight operations, provided the vent system does not allow cross-flow through the tank.