Showing papers on "Ullage published in 1972"

Fuel tank inerting system with means to improve thermal stability of fuel

Abstract: A fuel tank inerting system characterized in the provision of mixing means such as an aspirator or ejector to promote the diffusion equilibrium between the fuel and the nitrogen-rich ullage gas in the fuel tank to decrease the amount of oxygen dissolved in the fuel to just a few parts per million (ppm) thereby to improve the thermal stability of the fuel such that the temperature at which the fuel enters the engine can be increased without causing excessive coking, slugging and varnishing. Such improved thermal stability of the fuel allows greater heat injection into the fuel or alternatively enables the use of a normally less thermally stable fuel at reduced fuel cost.

Liquid propellant thermal conditioning system test program

Abstract: Results are presented from more than 1500 hours of testing on a liquid hydrogen thermal conditioning unit. Test parameters included: mixer and vent flow rates; tank size; ullage volume; pressurant gas; pressurant temperature; pressure level; and heat rate. Gaseous hydrogen and helium were used as pressurants. Analytical models were developed to correlate the test data and relate the performance to that anticipated in zero gravity. Experimental and theoretical results are presented which relate the variables controlling vapor condensation at a moving interface.

Tank liquid level determining apparatus

Abstract: A liquid level responsive device is described for use in tanker vessels to read out ullage directly on a gauge comprising in combination a strain gauge connected to an elongated buoyancy measuring means extending substantially vertically from substantially the bottom of the tank to substantially the top of the tank and sized in at least the upper extremity thereof so that the buoyant force of a liquid on the upper enlarged portion of the buoyancy means per linear incremental change in level of liquid in the tank becomes maximized as the level of liquid fills the tank.

Low Gravity venting of Refrigerant 11

Abstract: An experimental investigation was conducted in a five-second zero gravity facility to examine the effects of venting initially saturated Refrigerant 11 from a cylindrical container (15-cm diameter) under reduced gravitational conditions. The system Bond numbers studied were 0 (weightlessness), 9 and 63; the liquid exhibited a nearly zero-degree contact angle on the container surface. During the venting process, both liquid-vapor interface and liquid bulk vaporization occurred. The temperature of the liquid in the immediate vicinity of the liquid-vapor interface was found to decrease during venting, while the liquid bulk temperature remained constant. Qualitative observations of the effects of system acceleration, vent rate, and vapor volume presented. Quantitative information concerning the ullage pressure decay during low gravity venting is also included.

Selection of a surface tension propellant management system for the Viking 75 Orbiter.

Abstract: Discussion of the propellant management system requirements derived for the Viking 75 mission, and review of a series of surface tension propellant management system design concepts. The chosen concept is identified and its mission operation described. The ullage bubble and bulk liquid positioning characteristics are presented, along with propellant dynamic considerations entailed by thrust initiation/termination. Pressurization design considerations, required to assure minimum disturbance to the bulk propellant, are introduced as well as those of the tank ullage vent. Design provisions to assure liquid communication between tank ends are discussed. Results of a preliminary design study are presented, including mechanical testing requirements to assure structural integrity, propellant compatibility, and proper installation.

Low-gravity venting of refrigerant 11

Abstract: An experimental investigation was conducted in the Lewis Research Center's 5-Second Zero-Gravity Facility to examine the effects of venting initially saturated Refrigerant 11 from acylindrical container (15-cm diameter) under reduced gravitational conditions. The systemBond numbers studied were 0 (weightlessness), 9, and 63 and the liquid exhibited a nearzero-degree contact angle on the container surface. During the venting process, both liquid-vapor interface and liquid bulk vaporization occurred. The temperature of the liquid in theimmediate vicinity of the liquid-vapor interface was found to decrease during venting whilethe liquid bulk temperature remained constant. Qualitative observations of the effects ofsystem acceleration, vent rate, and percent vapor volume are presented. Also included arequantitative information concerning the ullage pressure decay during low-gravity venting.