Integrated Liquid/Steam Multiphase Flow Sensors for Geothermal Applications, Topic C57-14a

The advanced management of subsurface geothermal facilities requires accurate experimental information about the liquid/steam multiphase flow status in the subsurface. Such data is the key for the sites to establish models concerning fluid injection, transport, migration and leakage detection. The combination of subsurface temperature and pressure presents significant technical challenges for the implementation of the pressure and flow sensing devices, as well as the onboard signal processing and data transfer electronics. Semiconductor nanomembrane sensor skins are thin, mechanically and chemically robust materials that may be patterned in two dimensions to create multi-sensor element arrays that can be conformally attached onto material and model surfaces. The company has demonstrated the feasibility of nanomembrane transducer materials for the measurement of dynamic normal pressure and flow profile in high Reynolds-number environments. For real-time multiphase flow/turbulence measurements, the company proposes a time-of-flight based method by using 1) arrayed sapphire optical fibers to detect evanescent waves for multiphase measurement and 2) multiple pairs of serial-mounted high frequency nanomembrane sensing elements to pick up turbulence waveforms from upstream and downstream locations. This program will develop integrated liquid/steam multiphase flow sensors for subsurface monitoring. The team will further improve the technology by transitioning the integrated time-of-flight sensors and optic fiber sensors for multiphase flow measurements from their current concept to prototype stage products of use to the geothermal facilities. The arrayed sapphire fibers and pairs of miniaturized nanomembrane sensors will be integrated into one sensor housing, due to their small dimension. The team will fabricate prototype-level liquid/steam flow sensors using optimized materials and matching existing platforms. Current wireless electronics will be optimized to acquire, multiplex, store and process raw sensor array data. The commercialization potential of the multiphase flow sensor technology developed through this program lies in four areas, 1) sensors for the measurement of high frequency turbulence profile, 2) fiber optic sensors for the measurement of multiphase composition, 3) time-of-flight sensors for the measurement of multiphase flow profile, and 4) the data processing and communication modules.