STRATOS PERCEPTION, LLC — National Aeronautics and Space Administration SBIR Phase I: Z2

Description

Two-phase flow fluids can offer more power to forced-convective heat transport, because such fluids utilize phase change to dramatically increase (or decrease) heat transport capabilities over single-phase flow convection.nbsp;nbsp;Unfortunately, two-phase flow systems are inherently unstable and can accordingly introduce significant management challenges in the reduced and variable acceleration fields that are typically present on spacecraft.nbsp;While, in spacecraft, a stable separation of the fluid phases can be achieved in a phase-separator (i.e. via the radial acceleration about a vortex flow field), such stability is not easily available in the flow channels of implemented condenser or evaporators.nbsp;nbsp;The several flow regimes that can exist in two-phase flow channels (e.g. bubbly flow, slug flow, annular flow) are highly sensitive to the external acceleration field.nbsp;nbsp;nbsp;Further, flow regime, flow rate, heat-flux, flow quality, and pressure drop, and temperature are all interdependent, where a change in one causes (potentially dramatic) changes in the others.nbsp;nbsp;nbsp;This introduces a hard design and operational challenge due to the starkly different fluid and thermal properties that can exist as a function of the flow regime in a two-phase flow channel, and the risky thermal transients that can occur.nbsp;nbsp;This problem can be substantially reduced by an intelligent sensor that can discern the thermal and fluid characteristics in a two-phase flow channel and provide such information to an intelligent control system in real-time.nbsp;This research develops such an intelligent sensor for two-phase flow implementations in spacecraft, providing a capability to both sense, and via intelligent control, precisely specify the flow regime and flow quality of a two-phase flow channel.nbsp;