NASA 1998 SBIR Phase I


PROPOSAL NUMBER: 98-1 09.07-4242A

PROJECT TITLE: Tank Gauging in Low Gravity by Dynamical (e.g., Acoustic or RF) Signal Analysis

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Accurately gauging liquid quantity in tanks in low and zero gravity proves difficult because surface tension forces migrate vapor roughly to tank center and away from any solid probes. Small accelerations also cause slosh states which frustrate static measurements. Gauging systems on spacecraft must also handle cryogens accurately (and not, for example, add any significant heat to cryotanks). Foster-Miller proposes to combine its patented Dynamical Instruments nonlinear analysis with an acoustic or radio frequency resonant mode sensor. Existing efforts have correlated liquid volume roughly with resonant frequency. Unfortunately, slosh states and varying vapor-liquid orientations prevent conventional linear signal analysis from attaining useful accuracies. We propose to use Foster-Miller's dynamic nonlinear signal analysis methods to extract liquid quantity accurately (at least within ~5% with the acoustic method, possibly better with rf) from the irregular dynamics of sensor signals which result from liquid movement and changes in orientation with acceleration. Phase I will demonstrate concept feasibility through laboratory testing at room temperature with an air-water tank designed to simulate zero gravity fluid orientations. Based on obtained results, Phase II will pursue the advanced development of a real-time instrument suitable for demonstration and use with cryotanks in low gravity.

POTENTIAL COMMERCIAL APPLICATIONS

Accurate cryotank gauging will give NASA better information and thus better control of flight planning. Inexpensive, accurate, and non-invasive acoustic versions will benefit commercial automobiles and aircraft fuel gauging and industrial tankage, expecially of corrosive liquids.

NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR

Thomas W. Lovell
Foster-Miller, Inc.
350 Second Avenue
Waltham , MA 02154

NAME AND ADDRESS OF OFFEROR

Foster-Miller, Inc.
350 Second Avenue
Waltham , MA 02154