Abstract
For National Aeronautics and Space Administration’s space mission planning, tons of cryogenic propellants need to be stored under microgravity conditions. Because of heat leaks into cryogenic propellant tanks, thermal stratification develops from lack of natural convection leading to boil-off of precious propellants. A thermodynamic vent system operates with a jet mixer to reduce thermal gradients within the fluid and control pressure inside the tank. In this work, a Reynolds-averaged Navier-Stokes–based computational fluid dynamics model was developed to study the fluid dynamics of jet-induced mixing and jet impingement on the large ullage bubble in the Tank Pressure Control Experiment (TPCE) under microgravity conditions. First, the computational model was benchmarked against existing experimental flow visualization data on the jet impingement. The jet mixing was then compared quantitatively with correlations for the jet radius to analyze the volumetric flow rate of the jet due to entrainment in the near field of the nozzle. The findings show that the confinement of the jet due to the ullage and the walls contributes positively to the jet entrainment rate, thus increasing the jet volumetric flow rate. In addition, the turbulence parameters are plotted to study the flow development for the TPCE case where the jet does not penetrate the ullage. Last, the model was used to determine the jet Weber number for penetration on the ullage bubble by varying jet inlet velocities. Numerical results show that the jet can penetrate the ullage when the jet Weber number is greater than 1.3.
Acronyms
AHTR: | = | Advanced High Temperature Reactor |
CFD: | = | computational fluid dynamics |
CFM: | = | cryogenic fluid management |
CSF: | = | continuum surface force |
LAD: | = | liquid acquisition device |
LOCA: | = | loss-of-coolant accident |
NASA: | = | National Aeronautics and Space Administration |
RANS: | = | Reynolds-averaged Navier-Stokes |
SFR: | = | sodium fast reactor |
SST: | = | shear stress transport |
TKE: | = | turbulent kinetic energy |
TPCE: | = | Tank Pressure Control Experiment |
TVS: | = | thermodynamic vent system |
VOF: | = | volume of fluid |
1-D: | = | one-dimensional |
2-D: | = | two-dimensional |
Acknowledgments
The authors at Rensselaer Polytechnic Institute would like to thank the technical support provided by Michael F. Harris of NASA Kennedy Space Center. The authors would also like to thank the technical support from Mamoru Ishii of Purdue University and Wei Ji of Rensselaer Polytechnic Institute.
Disclosure Statement
No potential conflict of interest was reported by the authors.
Correction Statement
This article has been corrected with minor changes. These changes do not impact the academic content of the article.