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.

Fuel tank ullage pressure reduction

Abstract: An apparatus reduces the pressure in a fuel tank ullage including a first conduit for connection to the fuel tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the fuel tank ullage, a separation module having an inlet connected to the first conduit, a separation membrane, a permeate outlet separated from the inlet by the separation membrane, and a retentate outlet, a second conduit connected to the permeate outlet for connection to the fuel tank, a vapor pump associated with the second conduit for creating a low pressure in the separation module near the permeate outlet as to induce selected vapors to pass through the separation membrane, a vent associated with the retentate outlet to vent retentate to atmosphere, a hydrocarbon detector to detect hydrocarbon concentrations in the vent, and a controller to receive inputs from the pressure sensor and the hydrocarbon detector and output control signals to the vapor extractor and the vapor pump to pull vapor from the ullage when the pressure exceeds a pressure threshold and return permeate to the tank and permit relatively hydrocarbon-free air to be released through the vent, thereby reducing the pressure in the ullage.

Numerical Modeling of Pressurization of a Propellant Tank

Abstract: An unsteady finite volume procedure has been developed to predict the history o pressure, temperature and mass flow rate of the pressurant and propellant during the expulsion of the propellant from a tan. The time dependent mass, momentum and energy conservation equations are solved at the ullage space. The model accounts for the change in the ullage volume due to expulsion of the propellant. It also accounts for the heat transfer from the tank wall and propellant to the ullage gas. The procedure was incorporated in the Generalized Fluid System Simulation Program (GFSSP). The results of several test cases were then compared with a published correlation of pressurant requirements for a given displacement of propellant. The agreement between the predictions and the correlation was found to be satisfactory.

Volatile organic chemical tank ullage pressure reduction

Abstract: An apparatus reduces the pressure in a volatile chemical tank ullage including a first conduit for connection to the volatile chemical tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the volatile chemical tank ullage, a separation module having an inlet connected to the first conduit, a separation membrane, a permeate outlet separated from the inlet by the separation membrane, and a retentate outlet, a second conduit connected to the permeate outlet for connection to the volatile chemical tank, a vapor pump associated with the second conduit for creating a low pressure in the separation module near the permeate outlet as to induce selected vapors to pass through the separation membrane, a vent associated with the retentate outlet to vent retentate to atmosphere, a VOC detector to detect VOC concentrations in the vent, and a controller to receive inputs from the pressure sensor and the VOC detector and output control signals to the vapor extractor and the vapor pump to pull vapor from the ullage when the pressure exceeds a pressure threshold and return permeate to the tank and permit relatively VOC-free air to be released through the vent, thereby reducing the pressure in the ullage

Fueling system vapor recovery and containment performance monitor and method of operation thereof

Abstract: A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors. The disclosed methods and apparatus also provide for the determination of fuel dispensing system vapor containment integrity, and the differentiation of true vapor recovery failures as opposed to false failures resulting from the refueling of vehicles provided with onboard vapor recovery systems.