Topic
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 published on a yearly basis
Papers
More filters
01 Jul 1974
TL;DR: In this paper, an analysis to predict the pressurant gas requirements for the discharge of cryogenic liquid propellants from storage tanks is presented, along with an algorithm and two computer programs.
Abstract: An analysis to predict the pressurant gas requirements for the discharge of cryogenic liquid propellants from storage tanks is presented, along with an algorithm and two computer programs. One program deals with the pressurization (ramp) phase of bringing the propellant tank up to its operating pressure. The method of analysis involves a numerical solution of the temperature and velocity functions for the tank ullage at a discrete set of points in time and space. The input requirements of the program are the initial ullage conditions, the initial temperature and pressure of the pressurant gas, and the time for the expulsion or the ramp. Computations are performed which determine the heat transfer between the ullage gas and the tank wall. Heat transfer to the liquid interface and to the hardware components may be included in the analysis. The program output includes predictions of mass of pressurant required, total energy transfer, and wall and ullage temperatures. The analysis, the algorithm, a complete description of input and output, and the FORTRAN 4 program listings are presented. Sample cases are included to illustrate use of the programs.
10 citations
••
TL;DR: In this paper, the authors present test data analysis of the liquid nitrogen vented chill, no-vent fill (NVF) experiments on the CRYOTE-2 tank, and while not originally intended, were performed in a somewhat parametric fashion.
10 citations
01 Oct 1991
TL;DR: In this paper, the results of no-vent fill testing with liquid hydrogen in a 1.2 cubic foot (34 liter) stainless steel tank are presented, and three liquid injection techniques are employed; top spray, upward pipe discharge, and bottom diffuser.
Abstract: Experimental results of no-vent fill testing with liquid hydrogen in a 1.2 cubic foot (34 liter) stainless steel tank are presented. More than 40 tests were performed with various liquid inlet temperatures, inlet flowrates, initial tank wall temperatures, and liquid injection techniques. Fill levels equal to or exceeding 90 percent by volume were achieved in 40 percent of the tests with the tank pressure limited to a maximum of 30 psia. Three liquid injection techniques were employed; top spray, upward pipe discharge, and bottom diffuser. Effects of each of the varied parameters on the tank pressure history and final fill level are evaluated. The final fill level is found to be indirectly proportional to the initial wall and inlet liquid temperatures and directly proportional to the inlet liquid flowrate. Furthermore, the top spray is the most efficient no-vent fill method of the three configurations examined. The success of this injection method is primarily due to condensation of the ullage vapor onto the incoming liquid droplets. Ullage condensation counteracts the tank pressure rise resulting from energy exchange between the fluid and the warmer tank walls, and ullage compression. Upward pipe discharge from the tank bottom is the next most efficient method. Fluid circulation induced by this fill configuration tends to diminish thermal stratification in the bulk liquid, thus enhancing condensation at the liquid gas interface.
10 citations
••
25 Jul 2010
TL;DR: In this article, a suite of predictive tools have been developed that can aid in the design and management of propellant tanks, including a multi-node lumped parameter code, a multiphase CFD code, and a hybrid procedure that utilizes CFD in conjunction with a lumped parameters based internal boundary between the ullage and the liquid.
Abstract: Summary The pressure of propellant and oxidizer tanks has to be maintained within a narrow margin and is critical to the proper functioning of the liquid propulsion system. Several control mechanisms such as venting and spray bars are specifically deployed in the tankage to ensure that the pressure in the tank is restricted to the design margins. In this paper a suite of predictive tools have been developed that can aid in the design and management of propellant tanks. The analysis tools comprise of a multi-node lumped parameter code, a multi-phase CFD code, and a hybrid procedure that utilizes CFD in conjunction with a lumped parameter based internal boundary between the ullage and the liquid. Each tool is specifically tailored towards a certain class of tank pressurization problems: for example the multi-node lumped parameter approach is particularly suited for long duration space tank applications, while the CFD approach is applicable to short duration injection based pressurization problems where mixing is the dominant physical mechanism. In long duration cases, where injection or venting based control systems can significantly alter the flow in the tank the hybrid approach is more appealing. A series of test cases from different regimes of tank pressurization were considered in this paper with the three approaches. The first simulation was based on the Saturn AS-203 self-pressurization fuel tank experiment in a low gravity environment. The complete duration of the test was analyzed with the multi-node lumped parameter code with average heat loads through the tank walls and the
10 citations
••
21 Jul 2008TL;DR: In this paper, a computational fluid dynamics (CFD) model is developed to simulate pressure control of an ellipsoidal-shaped liquid hydrogen tank under external heating in low gravity.
Abstract: A computational fluid dynamics (CFD) model is developed to simulate pressure control of an ellipsoidal-shaped liquid hydrogen tank under external heating in low gravity. Pressure control is provided by an axial jet thermodynamic vent system (TVS) centered within the vessel that injects cooler liquid into the tank, mixing the contents and reducing tank pressure. The two-phase cryogenic tank model considers liquid hydrogen in its own vapor with liquid density varying with temperature only and a fully compressible ullage. The axisymmetric model is developed using a custom version of the commercially available FLOW-3D software and simulates low gravity extrapolations of engineering checkout tests performed at Marshall Space Flight Center in 1999 in support of the Solar Thermal Upper Stage Technology Demonstrator (STUSTD) program. Model results illustrate that stable low gravity liquid-gas interfaces are maintained during all phases of the pressure control cycle. Steady and relatively smooth ullage pressurization rates are predicted. This work advances current low gravity CFD modeling capabilities for cryogenic pressure control and aids the development of a low cost CFD-based design process for space hardware.
10 citations