Cryogenic Multiphase Mass Flow Meter
Tech4Imaging, LLC has spent the last few years researching, developing and testing a new capacitance-based multiphase cryogenic flowmeter. Originally presented at CEC/ICMC’23 in Honolulu, the new design was able to achieve high accuracy across a broad range of flow rates, volume fractions and flow regimes. This development required overcoming several significant technological hurdles.
Tech4Imaging’s patent-pending mass flow meter relies on cross-correlation of a capacitance flow signal as fluid moves through the sensor. Measurement of flow velocity via cross-correlation required the development of a very high-speed data processing architecture, capable of collecting over 20,000 frames per second. The instrument measures the volume fraction of liquid in the region based on the difference in the dielectric constant between the liquid and gas phase of the cryogen. The volume fraction is then converted to a mass fraction based on the densities of the phases at the measured operating temperature. From the mass fraction and velocity, the mass flow rate can be calculated.
Cryogenic Multiphase Calibration Flow Loop
Calibrating and verifying the flowmeter required the construction of a multiphase cryogenic flow loop. This system was also a significant development by Tech4Imaging, capable of independently varying the flow rate and volume fraction to achieve a wide range of fluid flow conditions. The instrument and flow loop have been extensively tested with LN2 and are in the process of being tested with LH2. Adaptation to other cryogens like LOX or liquid methane is expected to follow. A paper summarizing the construction of the flow loop, the overall test regime, and the results will soon be published in the IOP Conference Series: “Materials Science and Engineering, Advances in Cryogenic Engineering.”
Cryogenic Multiphase Mass Gauging
Tech4Imaging is at the forefront of cryogenics research. Tech4Imaging’s other main technology called Electrical Capacitance Volume Tomography, or ECVT, is able to record images and phase distribution data of multiphase mixtures. Tech4Imaging has recently applied this technology to study microgravity mass gauging.
Fluids, often propellants, in microgravity don’t maintain a consistent and easy-to-measure level state. This limits the techniques that can be used to measure the amount of fluid remaining in a tank, a critical parameter for long-term space missions.
Traditional methods have serious drawbacks in terms of accuracy, reliability and response time. ECVT, however, has tremendous potential to solve these problems. In an upcoming series of papers in the journal Cryogenics and the journal Sensors, Tech4Imaging will demonstrate the construction and testing of a prototype sensor, as well as a variety of techniques to improve the accuracy of the reconstructed mass fraction using imaging and newly developed machine learning algorithms.
Capacitance technology has many advantages in the field of cryogenics due to its non-intrusive, non-hazardous nature, its fast response times and its high degree of sensitivity. Tech4Imaging hopes to continue to push the boundaries of new research into cryogenic fluid dynamics using its newly developed technology.
