Assessment of prediction and efficiency parameters for cryogenic no-vent fill

Numerical Modeling of No Vent Filling of a Cryogenic Tank

The purpose of this paper is to reveal the dynamic mass transfer effects between gas and liquid on pressure fluctuations in a space micropump using our proposed computational model of gas–liquid mass transfer. Complex dissolution and evolution processes were applied to achieve accurate dynamic gas–liquid mass transfer predictions in the micropump. The validation of experiments was conducted by measuring the performance characteristics of the micropump, and the mass transfer model was verified by a dissolved oxygen concentration experiment in plug discharge flow. Based on this, four conditions including unsteady single-phase, two-phase without mass transfer, dissolution, and coexisting dissolved–released flows calculations are discussed to clarify the frequency contents, generation reasons, and propagation law. Combined with entropy production analysis, the pressure fluctuation influenced by the dissolution and evolution is illustrated. The results exhibit that the evolution of the gas is located on the head of the long blade suction surface in the impeller. When a unidirectional gas-to-liquid dissolution process occurs, the fluctuating amplitude of the characteristic dominant 5 fn is significantly weakened; otherwise, when dissolution and evolution coexist, the amplitude is significantly promoted as the released gas increase the flow instability. In addition, the distributions of local high entropy production induced by mean and fluctuating velocity gradients overlap that of large mass transfer rates and high amplitude of the mixing frequency in the volute, exhibiting the relationship between entropy production, mass transfer, and flow instability. The current study provides a guidance that the dissolved gases’ concentration must be controlled strictly to avoid the evolution of gas for the safety and stability of the space hydraulic system.

Dissolution and evolution effects on pressure fluctuations in a space micropump

Results from neutron imaging phase change experiments with LH2 and LCH4

Modeling, simulation and analysis of tank thermodynamic behaviors during no-vent LNG bunkering operations

Test Data Analysis of the Vented Chill, No-Vent Fill Liquid Nitrogen CRYOTE-2 Experiments

Test data analysis of the thermodynamic vent system-augmented top spray injector liquid nitrogen transfer experiments

Future long duration manned and robotic missions will require efficient methods with which to transfer cryogenic propellant from a depot storage tank to the customer spacecraft. In the absence of a cryocooler heat exchanger, the cold propellant itself can be used to chill down the warm transfer line hardware and receiving tank. To deal with issues associated with transferring propellant in reduced gravity, a non-vented filling method is proposed where the receiving tank hardware is pre-chilled to some target temperature cold enough to allow a high final fill fraction in the receiving tank without venting. Predicting this target temperature, however, is difficult. In this paper, two parameters based on thermodynamics are proposed that can be used to gauge whether or not a cryogenic propellant transfer will fail or not. The predictive parameter is applied to the 42 historical no-vent fill experiments from Moran et al. [1] and 38 experiments from Hartwig et al. [2] where testing was conducted over a wide range of liquid injectors and initial conditions. Results indicate a 100% success rate that the failure of a non-vented transfer is predictable for a given initial state and desired final state. Meanwhile the efficiency parameter yields insight into the success of particular injectors on the same tank. 

Predictive and Efficiency Parameters for Non-vented Cryogenic Propellant Fill

The placement of cryogenic fuel/propellant depot stations in Earth orbit has the potential to transform the nature and operations for many types of spaceflight missions. Today, spaceflight missions are almost universally required to carry the entire amount of fuel required for the mission, for the entire duration of the mission, from the point of launch. This is the rough equivalent of making a drive from Ohio to California, requiring the traveler to bring along the total sum of gasoline required for the entire trip, without being able to ‘fill-up’ anywhere along the route. Obviously, this framework of travel greatly encumbers the breadth, scope, and efficiency of potential journeys. Cryogenic fuel/propellant depots have not been implemented because many technical, operational, and engineering challenges still exist. These must be overcome prior to the placement of usable on-orbit propellant depots. This thesis investigates three specific engineering challenges related to on-orbit propellant depots, and presents the current state, technological challenges, and ultimate benefits of on-orbit cryogenic refueling.

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Justin Clark

Papers

Test Data Analysis of the Vented Chill, No-Vent Fill Liquid Nitrogen CRYOTE-2 Experiments

Assessment of prediction and efficiency parameters for cryogenic no-vent fill

Test data analysis of the thermodynamic vent system-augmented top spray injector liquid nitrogen transfer experiments

Predictive and Efficiency Parameters for Non-vented Cryogenic Propellant Fill

On-Orbit Cryogenic Refueling: Potential Mission Benefits, Associated Orbital Mechanics, and Fuel Transfer Thermodynamic Modeling Efforts