Ultrasonic instrumentation for cryogenic fluid aboard orbiting spacecraft faces problems in at least three areas: transducers must withstand temperatures as low as 20 K; location of transducers must be minimally-invasive and permit measurement of desired parameters; and the signal processor must compute flow parameters while neglecting noise. In Phase I, analysis and experiments will concentrate the first two problems. To solve the thermal problems, novel, slender transducers will be constructed using materials of nearly-matched expansion coefficients and with point-contact coupling. Novel deployment includes acoustically-isolated, point-source flowmeter transducers and a modified H2-slush density sensor of 1x3 mm cross section for mass gaging and mass-flow metering. A commercial unit will be applied in processing signals for feasibility demonstrations in water and in cryogens. A method of reducing coherent noise will be investigated which could improve the accuracy of non-invasive ultrasonic measurements by a factor of ten.
Potential Commercial Applications:A need exists for a non-invasive flowmeter for low-density hydrocarbon fluids, some gases (including steam), and two-phase fluids at temperature extremes or in a malevolent environment.STATUS: Phase I Only
