Study of Gas Core Behavior of Passive Cyclonic Two-Phase Separator for Microgravity Applications

Abstract

Separating gas-liquid two-phase flow is of practical importance for many space engineering systems. While droplet and bubble removal is a naturally occurring phenomenon in most terrestrial situations, the absence of buoyancy in a microgravity environment often results in situations where two disparate phases have no distinct inclination to separate from one another. Passive cyclonic separators can perform this task without moving parts and the reliability concerns of active separators. In such separation devices, separation efficiency is strongly influenced by the gas core behavior. Based on experimental and numerical investigations, the behavior of the gas core with two-phase injection is studied. A control-volume model is developed to capture the relevant physics of the flow in the separator. It is shown that the injection nozzle design, swirl number, and volumetric gas quality all have a major influence on the core size. The present investigation covers a range of volumetric quality from 0 to 0.75, and a range of swirl number from 17 to 28. Both homogeneous and non-homogeneous nozzles are used. The implications of the results are discussed in detail.