A Statistical Comparison of Various Fluids for a Drift Flux Model in Reduced Gravity Two‐Phase Slug Flow
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The desire to utilize enabling, two-phase (gas-liquid) systems for advanced life support and thermal management are driven by NASA's exploration initiative and the early development of commercial space interests. Two-phase flow heat transfer is highly advantageous over single-phase systems. Two-phase fluid loops provide significant thermal transport advantages over their single-phase counterparts and are able to carry more energy per unit mass than single-phase systems at reduced pumping power per unit mass. These advantages alone offer great reductions in both mass and volume, as well as power requirements; unfortunately, the ability to predict two-phase phenomena such as flow regime transitions and void fraction at microgravity conditions is greatly limited and its development will facilitate the utilization of two-phase systems. The drift flux model is a useful tool to predict the void fraction and thus, the pressure drop. Results of a statistical analysis indicate that for water/air and water-Zonyl/air fluids, the drift velocity, Ugj, is -0.070 and the distribution parameter, C0, is 1.269. These results indicate that the surfactant used had little effect on the model compared to the liquid density difference from the water-glycerin mixture as well as the liquid density and vapor density differences from the refrigerants R12 and R134a. © 2005 American Institute of Physics.
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