Determination of Henry’s law constant and the diffusion and polytropic coefficients of air in aviation fuel

The volume change of air microbubbles on surface nucleation sites was studied experimentally and compared with predictions. Measurements were used to determine the polytropic constant, the diffusion coefficient, and the Henry’s law constant of air in distilled water, dodecane, and JP-8 aviation fuel. The liquids were exposed to sub-atmospheric pressures, but above their vapor pressures. In one type of experiment, bubble size reduction was recorded as the liquid’s ambient pressure was increased from a low pressure to atmospheric pressure though a series of step increases. The results were used to determine the polytropic constant. In another type of experiment, bubble growth was monitored in time following a sudden reduction in the liquid’s pressure from ambient. The Epstein–Plesset model of mass diffusion was coupled with a Lipschitzian optimization technique to determine the values of the diffusion coefficient and Henry’s law constant.