Designing and Testing an Experimental Platform in Support of Partial Gravity Two-Phase Fluid Physics Modeling
Abstract
Several nations are on the eve of returning to the Moon, establishing permanent research stations, and utilizing the Lunar resources. Developing and experimentally validating two-phase fluid dynamic models for different gravitational regimes is critical for designing reliable Lunar and Martian hardware systems, to include human life support systems, cryogenic fuel management and in-situ resource utilization (ISRU). It is well known that in a microgravity environment, surface tension effects (liquid in contact with solid) dominate over buoyancy, whereas in most earth-based processes, buoyancy overcomes surface tension. The balance between these forces in partial gravity is relatively unexplored, and the instrumentation to measure these balances had not yet been developed.
This work presents the development of an instrument designed to measure the balance between gas buoyancy and surface tension in 1 g for a variety of liquids, gases, and solid surfaces. The experimental results from this instrument system are being compared to an independently developed CFD model, also developed in the Aerospace Human Systems Laboratory (AHSL). In the future, the CFD models will be extrapolated to variable acceleration environments, while the instrument will be designed to fit within a flight project on the International Space Station (ISS) to collect empirical data in artificial/altered gravity or, eventually, in a steady state 1/6th g environment on the Lunar surface. Parametric empirical data will be compared with the CFD data to in order to generate future models. The experimental device is a custom designed and built, multi-axis, high-speed imaging system. The development, calibration, and validation of the imaging and gas injection systems have been completed and characterized. Experimental results are highly correlated with CFD models in 1 g. The instrument is accurate to within 3.52% when measuring the dimensions of a gas bubble, and repeatable to within 1.42% in bubble volume measurements.
Subject
two-phase fluidsbubble separation
instrument design
systems engineering, partial gravity
space
cryogenic fuels
life support systems
ISRU
Citation
Varnum-Lowry, Daniel (2020). Designing and Testing an Experimental Platform in Support of Partial Gravity Two-Phase Fluid Physics Modeling. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /191900.