Optical Mass Sensor for Multi-Phase Flows

Optical Mass Sensor for Multi-Phase Flows (TOP8-91)
Noninvasive device provides both static and dynamic measures of void fraction in gas-vapor mixes
NASA's Marshall Space Flight Center is offering opportunities for its new fiber optic mass flow sensor system. Capable of measuring multi-phase flows in a pipe, the technology is minimally invasive, cost effective, retrofittable, and compact. MSFCs new technology combines high accuracy, intrinsically safe operation, and low-cost flow sensing for virtually any optically transparent medium, providing a superior product for measuring multi-phase flows.

The Technology
Unlike commercial turbine and Venturi-type sensors, which are flow intrusive and prone to high error rates, NASA's new flow sensor technology uses an optical technique to precisely measure the physical characteristics of a liquid flowing within a pipe. It generates a reading of the flows density, which provides a highly accurate mass flow measurement when combined with flow velocity data from a second optical sensor. NASA's sensor technology provides both a void fraction measurement, which is a measurement of the instantaneous gas/liquid percentage of a static volume and a quality measurement, which is the fraction of flow that is vapor as part of a total mass flow. It also provides a direct measurement of the gas/liquid concentration within the flow, making it suited for real-time measurement of multi-phase flows. The technology was originally developed to accurately determine the flow rates and tank levels of multi-phase cryogenic fuels used on various NASA vehicles including the Space Shuttle and in ground-based propulsion testing. It can also be used for a wide range of gas/liquid ratios, flows with complex cross sectional profiles, flows containing bubbles or quasi-solids, and essentially any liquid, gas, or multi-phase flow that can be optically characterized. Because it is insensitive to position, the new technology also has potential for use in zero-gravity tank level sensors.
The NASA optical mass flow sensor as designed for in-line cryogenic fuel measurements.
  • Provides void fraction and quality values through real-time flow rate measurement
  • Has no moving parts
  • Keeps all sensor components external to flow path and insensitive to pipe material
  • Is safe from electromagnetic interference and poses no radiation hazard
  • Retrofits to existing piping systems from 0.5 to 12 in diameter
  • Accommodates various flow schemes found within pipes including bubbles
  • Is a potentially inexpensive sensor design

  • Cryogenic liquid and fuel flow, handling, and storage measurements
  • Oil and gas industry multi-phase flows
  • Industrial, automotive, and aerospace multi-phase flows
  • Powder spray coatings
  • Food processing
  • Chemical processing, handling, and storage
  • Zero-gravity liquid tank level sensors
Technology Details

-V. Korman. "Density and Cavitating Flow Results from a Full-Scale Optical Multiphase Cryogenic Flowmeter", (2007)
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