System for monitoring physical characteristics of fluids
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsEugene Trinh, Taylor G. Wang
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Abstract
An apparatus and method are described for measuring physical characteristics of a fluid, by placing a drop (16) of the fluid in a bath (14) of a second fluid and passing acoustic waves through the bath. The applied frequency of the acoustic waves is varied, to determine the precise value of a frequency at which the drop undergoes resonant oscillations. The resonant frequency indicates the interfacial tension of the drop (16) in the bath (14), and the interfacial tension can indicate physical properties of the fluid in the drop.
Claims14
Apparatus useful in oscillating a drop of a first fluid when surrounded by a bath fluid, comprising:
- a container for holding a bath fluid and for receiving a drop of the first fluid within the bath fluid;
- transducer means coupled to said container and energizable for generating acoustic energy and conducting it into bath fluid lying in said container;
- means for energizing said transducer means;
- and
- means for sensing oscillations of the drop of first fluid;
- said energizing means being frequency controllable to alter the frequency to a value which produces resonant oscillations of said drop of first fluid.
Apparatus for oscillating a drop of a first liquid without contacting a solid, comprising:
- a container;
- a second liquid lying in said container and forming a liquid bath large enough to completely envelope said drop, said second liquid being substantially immiscible and chemically unreactive with said first liquid of said drop;
- acoustic transducer means coupled to said second liquid;
- and
- means for energizing said transducer means to produce acoustic waves in said second liquid of a frequency which is resonant to said drop lying in said second liquid.
Apparatus for oscillating and sensing oscillations of a substantially opaque suspended drop, comprising:
- light source means for directing a beam of light of a diameter greater than the diameter of said drop when it is quiescent, at said drop;
- means positioned on a side of said drop opposite said light source means, for detecting the amount of light falling on a slit-like area of predetermined size whose center portion is blocked from receiving light of said beam by said drop;
- and
- means for oscillating said drop so its diameter, as measured parallel to the length of said slit-like area, repeatedly changes.
A method for sensing interfacial surface tension at a surface of a first liquid comprising:
- introducing a drop of the first liquid in a bath of a second liquid;
- applying acoustic energy to said bath of second liquid;
- sensing oscillations of said drop;
- and
- varying the frequency of said applied acoustic energy to a frequency at which said drop undergoes resonant oscillations.
Dependencies are inferred from the claim text.