Dielectric coefficient and density of subcooled liquid oxygen Original Research Article

The results of high precision dielectric coefficient measurements of subcooled liquid oxygen in the temperature range from 56 to 91 K and under pressures up to 1 MPa are reported. The measurements are performed using a three-terminal flat plate capacitor and a single-frequency, ultra-precision capacitance bridge. Measurement results are combined with the previously published data in different pressure and/or temperature ranges to express the dielectric coefficient and the Clausius–Mossotti relation in an equation form. This new expression covers both the liquid and the gaseous state, and predicts the density of oxygen to better than 0.1% over the entire range of interest. The results reported in this paper are expected to be especially useful for capacitance-based measurements involving fluid oxygen such as liquid level and void fraction measurements of two phase flow.