Ullage

About: Ullage is a research topic. Over the lifetime, 501 publications have been published within this topic receiving 4704 citations. The topic is also known as: headspace.

Proton ullage motor observations as possible precursors to explosions in space

Abstract: Two optical observation campaigns during 1999 and 2000 were conducted to monitor the optical characteristics of the Proton 4 ullage motor population located in mainly geostationary transfer orbits about the earth. This study attempted to physically characterize the intact ullage motors and those that have exploded in space using conventional large aperture binocular optics and 3rd generation image intensified video (commonly employed for non-military astronomical observation) in order to determine if optical signatures could reveal evidence as to which motors might be candidates for explosion. We find that some motors do not spin down through normally expected damping; explosions do not consistently result in the catastrophic destruction of the parent body involved; accelerations in the rotation rates of some intact ullage motors have been discovered; some fragmentations do not result in an increase in rotation of the surviving parent as might be expected. No conclusive evidence was obtained that could lead to positively identifying precursors for future explosion. Yet, through statistical methodology we determined that there is a strong probability of additional explosions until the majority of motors launched between 1982 and 1996 decay from orbit. We estimate the probability of at least one of 46 ullage motors currently in orbit exploding before decay is greater than 0.9999. The threat of explosions is not expected to be mitigated by natural decay of all candidate exploders for at least 50 years.

Calculation of oil tank volume and report generation system with trim and list corrections

Abstract: The capacity of ship’s oil tanks is usually designed as a tabled form in order to obtain oil volumes by using the measured ullage heights. However, the tank walls easily deform or distort due to lo...

Two-Dimensional, Two-Phase Modeling of Multi-Increment Bagged Artillery Charges

Abstract: : This report describes an extension to TDNOVA, a code whose purpose is the digital simulation of convective flamespreading through bagged artillery charges. TDNOVA is based on the numerical solution of the axisymmetric, two- dimensional equations which govern the macroscopic aspects of the flow of a two- phase, heterogeneous mixture. Of principal interest are the inter-play among the venting characteristics of the ignition system, the properties of the bag and the distribution of ullage during the period of flamespreading, and the consequences of the path of flamespreading in respect to the structure of the longitudinal pressure field throughout the entire interior ballistic cycle.

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.