Mixing-induced ullage condensation and fluid destratification

Pressure control while minimizing the mass loss of liquid hydrogen is one of the key technologies required for the long-term storage of cryogenic propellants in microgravity in space, and the use of a thermodynamic venting system (TVS) has been considered as an effective means to solve this problem. In order to investigate the characteristics of pressure control by TVS technology, a cryogenic test platform for liquid hydrogen that integrated active and passive TVS was set up, a spray-bar exchanger and vapor-cooling screen were used to eliminate thermal stratification and realize the reuse of cold energy. Ten pressure-control tests using passive TVS (PTVS), mixing and active TVS (ATVS) strategies with heating powers of 0 W, 40 W and 80 W, were carried out. The single cycle time under different strategies, the effect of heating power on single cycle time, and the comparison of volume of the venting GH2 in different tests were analyzed in detail, the research showed that TVS technology could accurately control the pressure of cryogenic storage tanks within a predetermined range. An additional evaporation test was carried out using a direct venting method to compare with the above PTVS and ATVS tests, and the results showed that the venting volume of GH2 in unit time by the direct-venting method was close to that of the PTVS test with the heating power of 40 W, and the venting volume in unit time by the ATVS strategy was decreased by 87.3% compared to the direct-venting test.

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“…According to the energy jump boundary condition equation [19,20], the evaporation rate at the gas-liquid interface is .…”

Section: Thermal Model Analysis Of Storage Tanksmentioning

confidence: 99%

Experimental Investigation on Pressure-Control Characteristics of Liquid Hydrogen Tank Based on Active and Passive Thermodynamic Venting System Technology

Zhou

Zhang

et al. 2023

Processes

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“…In order to relax constraints induced by the use of cryogens, and thus improve the accuracy of the tank power balance, Meserole et al [10] performed thermal stratification, SP, and pressure control experiments using Freon as simulant fluid. The use of Freon, as a simulant fluid, allows experiment close to room temperature (20 C) and thus lowers the driving potential for uncontrolled heat flux at the tank wall.…”

Section: Introductionmentioning

confidence: 99%

Active Insulation Technique Applied to the Experimental Analysis of a Thermodynamic Control System for Cryogenic Propellant Storage

Mer

Thibault

Corre

2016

Journal of Thermal Science and Engineering Applications

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A technological barrier for long-duration space missions using cryogenic propulsion is the control of the propellant tank self-pressurization (SP). Since the cryogenic propellant submitted to undesired heat load tends to vaporize, the resulting pressure rise must be controlled to prevent storage failure. The thermodynamic vent system (TVS) is one of the possible control strategies. A TVS system has been investigated using on-ground experiments with simulant fluid. Previous experiments performed in the literature have reported difficulties to manage the thermal boundary condition at the tank wall; spurious thermal effects induced by the tank environment spoiled the tank power balance accuracy. This paper proposes to improve the experimental tank power balance, thanks to the combined use of an active insulation technique, a double envelope thermalized by a water loop which yields a net zero heat flux boundary condition and an electrical heating coil delivering a thermal power Pc∈[0−360] W, which accurately sets the tank thermal input. The simulant fluid is the NOVEC1230 fluoroketone, allowing experiments at room temperature T ∈ [40–60] °C. Various SP and TVS experiments are performed with this new and improved apparatus. The proposed active tank insulation technique yields quasi-adiabatic wall condition for all experiments. For TVS control at a given injection temperature, the final equilibrium state depends on heat load and the injection mass flow rate. The cooling dynamics is determined by the tank filling and the injection mass flow rate but does not depend on the heat load Pc.

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“…The most effective way of performing active mixing in the tank is to introduce a jet of liquid along the tank's centerline (Messerole 1997;Boeing Aerospace 1989). Some of the benefits of the jet-induced active mixing include a reduction in thermal stratification, a catalyst in the self-pressurization process, faster on-orbit transfer times, and the possible use of small heat exchangers, such as the TVS.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Jet-Induced Geysers in Reduced Gravity

Marchetta

Benedetti

2008

Microgravity Sci. Technol.

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Control of cryogenic propellant tank pressure during tank refueling and expulsion in low gravity is an important technical challenge to overcome for future long duration missions in space. One method proposed to control tank pressurization involves the use of jet-induced geysers. Two-dimensional computational models have been developed and used with limited success in previous efforts to predict geyser heights in microgravity. A three-dimensional flow simulation is used to model jet-induced geysers in reduced gravity. Geyser flows are commonly characterized by the presence of turbulent jets, transient flow, deforming free surfaces, and surface tension effects. As is the case for many turbulent flow applications, accuracy in simulating complex turbulent flows is critically dependent on the selection of a suitable turbulence model. The sensitivity of the simulation geyser predictions to a suite of popular turbulence models is assessed. Simulation results are compared to available experiment results. By expanding upon the work already completed, the model is used to simulate a broad range of cases within the experiment test matrix. Simulation results suggest the two dimensional simulation using the k-ε turbulence model provides the most accurate results for jetinduced geysers in reduced gravity when compared to available experiment data.

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Mixing-induced ullage condensation and fluid destratification

Cited by 12 publications

References 4 publications

Experimental Investigation on Pressure-Control Characteristics of Liquid Hydrogen Tank Based on Active and Passive Thermodynamic Venting System Technology

Experimental Investigation on Pressure-Control Characteristics of Liquid Hydrogen Tank Based on Active and Passive Thermodynamic Venting System Technology

Active Insulation Technique Applied to the Experimental Analysis of a Thermodynamic Control System for Cryogenic Propellant Storage

Simulation of Jet-Induced Geysers in Reduced Gravity

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