Gee Tsang
Published: 1977
Total Pages: 48
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Theoretical investigations show that the presence of frazil ice in water can be quantitatively measured by its effect on the conductivity and the permittivity of the water. At frequencies much lower than 10 7 Hz, the frazil ice effect on conductivity predominates, and at frequencies much higher than 10 7 Hz, the ice effect on permittivity is predominant. An experimental instrument based on the resistance (i.e. conductivity) principle has been constructed and tested. Experiments were performed in a cold room with frazil ice produced in a beaker. The experiments showed that the laboratory instrument could quantitatively sense the presence of ice. The detailed circuit of the experimental instrument is shown. Some modification of the circuit and the probe for improving the instrument are suggested as a consequence of the laboratory experiments and further theoretical investigations. The concentrations of frazil ice measured by the experimental instrument were by average about three times the concentration calculated theoretically. If the frazil ice crystals are assumed to have elongated spheroidal shapes with a length to breadth ratio of 10:1, the measured concentrations are about twice the calculated concentration. Further theoretical investigation is needed to explain this puzzle. The puzzle, however, is beneficial because it decreases the sensitivity of the instrument. This report describes phase I of an instrument development project. The design and production of and improved and manufacturable instrument will be phase II of the project.
