Analysis of a Microwave Void Fraction Meter

The eigenvalue problem of an open-ended, dielectric loaded, circular cylindrical resonator is investigated by the boundary value and numerical techniques to compute the volumetric void fraction of gas bubbles in organic oil coolants used in some modern nuclear reactors. The resonator sensing section geometry is such that an organic coolant (or similar material) is transported through circular pipes acting as waveguides on both sides of the resonator section whose diameter is enlarged by a dielectric ring. The results are shown to be in excellent agreement with experimental data for the special case when the dielectric in the enlargement is the same the special case when the dielectric in the enlargement is the same as the transported material.