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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.


Papers
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Proceedings ArticleDOI
25 Jul 2016
TL;DR: In this paper, an Eulerian-Lagrangian approach is utilized to track the spray droplets and capture the interaction between the discrete droplet and the continuous ullage phase.
Abstract: A CFD model for simulating pressure control in cryogenic storage tanks through the injection of a subcooled liquid into the ullage is presented and applied to the 1g MHTB spray bar cooling experiments. An Eulerian-Lagrangian approach is utilized to track the spray droplets and capture the interaction between the discrete droplets and the continuous ullage phase. The spray model is coupled with the VOF model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. A new model for calculating the droplet-ullage heat and mass transfer is developed. In this model, a droplet is allowed to warm up to the saturation temperature corresponding to the ullage vapor pressure, after which it evaporates while remaining at the saturation temperature. The droplet model is validated against the results of the MHTB spray-bar cooling experiments with 50% and 90% tank fill ratios. The predictions of the present T-sat based model are compared with those of a previously developed kinetic-based droplet mass transfer model. The predictions of the two models regarding the evolving tank pressure and temperature distributions, as well as the droplets' trajectories and temperatures, are examined and compared in detail. Finally, the ullage pressure and local vapor and liquid temperature evolutions are validated against the corresponding data provided by the MHTB spray bar mixing experiment.

6 citations

Patent
Stephen Burnell1, Tim Leigh1
09 Jul 2015
TL;DR: In this article, an aircraft fuel system comprising a fuel storage facility for storing fuel and ullage, a separate ULLAGE storage facility, and a transfer arrangement for transferring Ullage between the fuel storage and the ULLage storage facility is described.
Abstract: The invention provides an aircraft fuel system comprising a fuel storage facility for storing fuel and ullage, a separate ullage storage facility for storing ullage, and a transfer arrangement for transferring ullage between the fuel storage facility and the ullage storage facility, wherein the transfer arrangement is capable of controlling the transfer of ullage based on a pressure input to the transfer arrangement. The invention also provides an aircraft with such a fuel system and a method of operating an aircraft.

6 citations

Proceedings ArticleDOI
16 Jul 2004
TL;DR: In this article, a series of thermodynamic venting system (TVS) tests was conducted in 1996 and 1998 using the Marshall Space Flight Center (MSFC) multipurpose hydrogen test bed (MHTB).
Abstract: To support development of a zero‐gravity pressure control capability for liquid hydrogen (LH2), a series of thermodynamic venting system (TVS) tests was conducted in 1996 and 1998 using the Marshall Space Flight Center (MSFC) multipurpose hydrogen test bed (MHTB). These tests were performed with ambient heat leaks ≈20 and 50 W for tank fill levels of 90%, 50%, and 25%. TVS performance testing revealed that the spray bar was highly effective in providing tank pressure control within a 7‐kPa band (131–138 kPa), and complete destratification of the liquid and the ullage was achieved with all test conditions. Seven of the MHTB tests were correlated with the TVS performance analytical model. The tests were selected to encompass the range of tank fill levels, ambient heat leaks, operational modes, and ullage pressurants. The TVS model predicted ullage pressure and temperature and bulk liquid saturation pressure and temperature obtained from the TVS model were compared with the test data. During extended self‐pressurization periods, following tank lockup, the model predicted faster pressure rise rates than were measured. However, once the system entered the cyclic mixing/venting operational mode, the modeled and measured data were quite similar.

6 citations

Patent
15 Jul 2016
TL;DR: In this paper, the authors describe a fuel deoxygenation system for an aircraft that includes a hydrocarbon recycler and a sealing wall between the ullage channel and the hydrocarbon recirculation channel.
Abstract: A fuel deoxygenation system for an aircraft includes a hydrocarbon recycler configured to recycle hydrocarbon gas into fuel. The hydrocarbon recycler includes a housing that partially defines an ullage channel configured to fluidly communicate with both an ullage of an aircraft fuel tank and a vent, wherein the housing partially defines a hydrocarbon recirculation channel configured to fluidly communicate with a liquid portion of a fuel tank. The hydrocarbon recycler also includes a membrane defining a sealing wall between the ullage channel and the hydrocarbon recirculation channel such that the membrane is in fluid communication with both the ullage channel and the hydrocarbon recirculation channel, wherein the membrane is configured to be permeable to hydrocarbons such that hydrocarbons in the ullage channel can pass through the membrane to the hydrocarbon recirculation channel and oxygen in the ullage channel to passes through to be vented.

6 citations

Journal ArticleDOI
TL;DR: In this article, a vapor-liquid equilibrium thermodynamic analysis was developed to assess the fuel vapor behavior in an aircraft fuel tank ullage, based on the Peng-Robinson equation of state and the extended corresponding-states method.

6 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202112
202018
201916
201810
201713
201613