Experimental and Numerical Investigation of Low-Gravity Fluid Dynamics
- Paper number
IAC-08.A2.2.10
- Author
Mr. Michael Vergalla, Florida Institute of Technology, United States
- Coauthor
Dr. Daniel Kirk, Florida Institute of Technology, United States
- Coauthor
Dr. Hector Gutierrez, Florida Institute of Technology, United States
- Coauthor
Mr. Garry Livesay, Florida Institute of Technology, United States
- Year
2008
- Abstract
Low gravity fluid dynamics is a field essential to future space applications, fluid management devices are used to influence the bulk of fluid to the desired location; however in the case of cryogenic propellants conventional propellant management devices are inadequate (membranes). These propellants are primarily used in multistage launch vehicles. During various types of maneuvers rocket propellants may experience slosh that may alter vehicle dynamics, possibly even leading to mission failure. Several main problems occur from cryogenic slosh. If the propellant is not near the pump inlet during restart or within the proper pressure and temperature range the engines manufacture does not guarantee restart. In addition, during coast phases (for example, from LEO to GEO) the sides of the tank are heated from the sun. If propellant sloshes up to hot regions of the tank, such as the upper dome, it may boil and pressurize the tank. This leads to a serious problem, typically tanks are vented for minor attitude adjustments and pressure management. When a fluid is expelled from these vents the added mass flow would cause an uncontrollable, disproportional side force. In order to have confidence in existing and developing CFD, accurate experimental data must be gathered for qualitative and quantitative comparison. Florida Institute of Technology’s Low-G Slosh Dynamics team is conducting analytical, numerical, and experimental simulations of low-gravity fluid dynamics. By using optical data acquisition and surface reconstruction (from stereoscopic CCD cameras) the empirical data set can be directly compared to computations. High quality experimental data will provide the mechanism for the understanding and establishing confidence for low-gravity CFD predictions. Various stages of complexity are explored. Two dimensional and three dimensional regimes are computed, including mesh dependence studies. Conventional CFD techniques rely on introducing an inertial source to the entire domain, while the presented approach defines inertial perturbations strictly on the solid wall boundaries. This allows the fluid to motion to be dominated strictly by its own inertia and intermolecular capillary forces. The experimental setup has interchangeable tank geometries mounted on a 4 DOF motion table for both ground and aircraft operations (KC-135). Post processing and data acquisition techniques are currently being refined. Wall wetting and wave frequency are measured. Motion and corresponding aircraft accelerations will be input into the CFD UDF to reconstruct exact conditions experienced by the experiment. In a larger scope understanding propellant slosh will aid in accurate prediction of launch trajectories.
- Abstract document
- Manuscript document
IAC-08.A2.2.10.pdf (🔒 authorized access only).
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