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.

Main-tank injection pressurization of high-energy propellants.

Abstract: : This report describes the work accomplished in demonstrating the feasibility of applying the main-tank injection (MTI) concept to high-energy propellants including hydrazine, mixed hydrazine, thixotropic hydrazine, nitrogen tetroxide, storable fluorine derivatives, and fluorine The MTI process provides propellant tank pressurization by the controlled injection of a hypergolic reagent to generate the required gas pressure resulting from the reaction with the propellant The technical approach included determination of theoretical pressurization system performance with the new propellants based on previous experience, selection of suitable reagents, and demonstration of process feasibility by tests performed in a 5 1/2-cu-ft test tank at 25, 150, and 300 psig Process feasibility for all the propellants except for Alumizine at the higher pressures No testing was completed using common ullage Although pressurization process control was adequately demonstrated during a nominal 2 1/2-minute propellant outflow, the reagents selected are not necessarily the optimum candidates Furthermore, the original and post test theoretical predictions of pressurization system performance have been invalidated by actual test results

Fluid quantity monitor

Abstract: PURPOSE: To improve the reliability by detecting gas pressure at the ullage of a container during the interruption of either one of flow in or flow out of a liquid and computing the liquid quantity in the container from the alteration of the gas pressure. CONSTITUTION: An electric control signal from a timer 13 excites a solenoid 15 to move a three-way valve 11. That is, the three-way valve 11 is moved between a first position where a flowing-in fluid from a scavenge pump 4 passing an input route 2 is supplied to a container 1 and a second position where the flowing-in fluid is transferred to a small tank 12 by closing the route 2 by the valve 11. The flow of the fluid to the container 1 is interrupted for a short time t1. After that. the solenoid 15 is excited by the timer 13 to switch the valve 11 again and open the route 2 and the flow of the fluid is changed to the container 1. In this way, the gas volume in the container 1 is changed periodically for a short time and the alteration of the gas pressure is sensed, so that the fluid quantity in the container 1 can be monitored.

Optimal Propellant Management Device for a Small-Scale Liquid Hydrogen Propellant Tank

Abstract: This chapter represents the second chapter of applying analytical modeling of PMDs in real cryogenic propulsion systems. The purpose of this chapter is to present the results of a trade study to compare performance of two different cryogenic propellant management devices inside a small-scale liquid hydrogen storage tank in the microgravity of space. The purpose of the trade study is to determine operating conditions under which a vane type and a screen channel LAD type are the optimal PMD. Analytical models are developed from first principles for both PMDs. Several different ullage bubble growth rates and initial locations within the tank are modeled. When coupled with the cryogenic bubble point model and ullage bubble models, the analytical flow code for gallery arms is used to simulate propellant tank drain in microgravity. A vane analytical model is also developed for microgravity fluid flow. Analytical models are used to compare PMD size, mass, and expulsion efficiency across a wide range of demand flow rates out of the tank. Finally, a critical flow rate range is defined below which vanes are the optimal PMD, above which screen channel LADs are the optimal choice for a small-scale liquid hydrogen propellant tank.

Evaluation of Fuel Fog Inerting Concepts

Abstract: : This report describes the theory and results of testing conducted to determine the feasibility of using condensate-formed fuel fog for inerting fuel tanks. The tests were performed in such a manner that the temperatures of the ullage space and one or two spray nozzles could be varied independently. A combination of spray temperatures and nozzle types was found that provided inerting over the complete range of ullage-space temperatures tested (+60 F to - 55 F). Further findings for the 6-cubic-foot ullage space (over liquid JP-4 fuel) were that 1.0-gph nozzles were sufficient but 0.4-gph nozzles were not, neither single hot nor single cold nozzles were sufficient, and inerting would not occur for all ullage conditions except when both hot and cold nozzles were used. It was found that the hot and cold spray temperature differentials could each be at least as low as 5 F. In addition, a fuel fogging preliminary design for the AH-1G Cobra helicopter is included.