Device for determining viscoelastic properties of liquids and a method for use
AssigneeUniversity of Houston
InventorsWilliam E. Van Arsdale, Hatim Motivala
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Abstract
An apparatus and method for measuring the viscoelastic properties of thin liquid films. A liquid film is placed between and adjacent to two plates, and one of the two plates is oscillated in a normal direction. Computer analysis of the force of the oscillations and the displacement of the oscillations reveals rheometric properties of the liquid.
Claims9
A method of determining viscoelastic properties of liquids comprising the steps of:
- placing a liquid circularly between and in contact with parallel plates;
- sinusoidally oscillating one of the plates in a direction normal to the other plate;
- measuring the radius of the fluid circle;
- measuring the force of the oscillations;
- measuring the displacement of the moving plate;
- measuring the mean distance between the plates;
- measuring the frequency of the oscillations;
- and
- determining G', the storage modulus, and G", the loss modulus, based on these measurements.
A method of determining G', the storage modulus, and G", the loss modulus, of non-Newtonian fluids comprising the steps of:
- placing a liquid circularly between and in contact with parallel plates;
- measuring the radius of the fluid circle;
- measuring the means distance between the plates;
- applying a sinusoidally oscillating force to one of the plates in a direction normal to the other plate, the force oscillations having a force amplitude and a frequency;
- measuring the force amplitude;
- measuring the frequency;
- measuring the displacement amplitude of the moving plate;
- measuring a phase lag between the displacement of the moving plate and the force oscillations;
- and
- determining G' and G" from these measurements.
An oscillatory squeezing flow rheometer for analyzing the behavior of thin fluid films comprising:
- parallel first and second plates for receiving a fluid film;
- an electric oscillatory shaker motor attached to the first plate, the motor oriented to sinusoidally oscillate the first plate normal to the second plate;
- means for measuring current supplied to the shaker motor, the motor and means calibrated such that the force of the oscillations can be measured as a function of electrical current input;
- means for measuring oscillation displacement at the first plate;
- and
- means for directly controlling the temperature of at least one of the two plates.
Dependencies are inferred from the claim text.